PHYS 450 Design Project Final Report:

Rubidium Atomic Clock

Josh Bendavid 492-0047David Burns 492-0860

Secretary Joseph Fox 496-8274Safety Officer Gaetan Kenway 486-7146Group Leader Carlos Paz-Soldan 489-3718

Devon Stopps 490-9611

April 10th, 2007

Abstract

We report on the detailed design, construction, and performance analysis of an optically pumpedatomic frequency standard based on the 6.8 GHz 87Rb hyperfine transition. Pumping of the F=1 groundstate was achieved using a custom built, tunable, external-cavity diode laser, locked to the Fg=2 →Fe=2 780 nm transition of 87Rb, using a saturated absorption spectroscopy. The design features amicrowave oscillator stabilized to the 6.8 GHz transition using feedback from a cyclic double resonanceresolved using frequency keyed modulation of the microwave source. Short and long term timing stabilitymeasurements could not be completed due to difficulties with the microwave frequency division andacquisition. Nevertheless, in addition to optically pumping F=1 ground state, our optical configurationis also capable of resolving the hyperfine structure of the 780nm transition in both 87Rb and 85Rb,allowing for this setup to be converted into a saturated spectroscopy experiment for the advanced physicslaboratory.

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Acknowledgements

The contributions of the numerous individuals, friends and faculty, who aided with this work cannot beoverstated. We would like to thank our supervisor, Dr. Hallin, for his invaluable insight and aid in securingthe capital required to fund this work. Many thanks also to Ken for the hours you invested helping andadvising us. You went far above and beyond what was required and we are appreciative. Dirk, Bernie, andKim, without your help, this work would not have been possible; we cannot thank you enough. AndrewJoyce, thank you very much for your help with the last minute PCB fabrication, we are all certainly indebtedto you. Finally, we must also thank all the other remaining faculty and friends, of whom there are many,who supported us through this project; we are grateful.

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Contents

1 Introduction 6

2 Quantifiable Objectives 62.1 Tuneable Laser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.2 Absorption Spectrum of Rubidium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.3 Optical Locking to Hyperfine Peak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.4 Double Resonance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72.5 Frequency Stability Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72.6 Refinement of Quantitative Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3 Theory 73.1 87Rb-beam Optically Pumped Atomic Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73.2 Littrow Configuration Tunable Diode Laser . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.3 Saturated Absorption Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4 Experimental Setup 104.1 Experimental Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.2 Littrow Tunable Diode Laser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114.3 Saturated Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4.3.1 Optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114.3.2 Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4.4 Microwave Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144.4.1 Quadrature Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144.4.2 Multiplexer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.4.3 Waveguide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.4.4 Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.4.5 Frequency Division . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4.5 Frequency/Timing Stability Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . 174.5.1 Short Term Frequency Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174.5.2 Long Term Timing Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4.6 Microwave Cavity and Waveguide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

5 Results 205.1 Tunable Laser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

5.1.1 Angle Dependence of Lasing Wavelength . . . . . . . . . . . . . . . . . . . . . . . . . . 205.1.2 Temperature Stabilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215.1.3 Constant Current Driver Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

5.2 Saturated Spectroscopy of Rubidium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

6 Responsibilities and Timeline 276.1 Organization of Team Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276.2 Gantt Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

7 Safety 28

8 Conclusion 29

9 Group Statement 29

References 29

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A Purchased Parts List 32

B Circuit Schematics 33B.1 Optical Lock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33B.2 PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35B.3 Temperature Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

C CAD Drawings 40

D Sample Code 51

E Data Sheets 59E.1 Tunable Laser Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59E.2 Microwave Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

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List of Figures

1 Energy level diagram of the 87Rb-beam D2 resonance line [18] . . . . . . . . . . . . . . . . . . 82 The Diffraction Grating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Overview of Experimental Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Laser Diode Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Laser diode comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 Saturated Spectroscopy Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 Microwave synthesis and feedback chain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 Electromagnetic Simulation of waveguide antenna . . . . . . . . . . . . . . . . . . . . . . . . . 169 Illustration of microwave modulation about a center frequency on the double resonance peak. 1610 Schematic circuit diagram of the microwave feedback circuit. . . . . . . . . . . . . . . . . . . 1611 Short term frequency stability instrumentation setup. . . . . . . . . . . . . . . . . . . . . . . 1712 Testing GPS reception in outdoor mounting location. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1813 Long term frequency stability instrumentation setup. . . . . . . . . . . . . . . . . . . . . . . . 1914 Gaussian Beam Profiles at Various Tuning Knob Angles . . . . . . . . . . . . . . . . . . . . . 2015 Tuning with Knob Angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2116 Step Response of Temperature Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2117 Lasing Current in Constant Current Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2218 Low Frequency Hyperfine Peaks of Natural Rubidium . . . . . . . . . . . . . . . . . . . . . . 2319 High Frequency Hyperfine Peaks of Natural Rubidium . . . . . . . . . . . . . . . . . . . . . . 2420 F=2→F’ 87Rb Transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2521 The effect of acoustic noise on the optical lock circuit. The satspec differential signal is shown

to oscillate outside the lock bandwidth at ∼1.2kHz . . . . . . . . . . . . . . . . . . . . . . . . 2622 Gantt Chart for Atomic Clock Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28A-1 Satspec optical side-lock circuitry schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33A-2 PCB top section is quadrature oscillator, bottom is high frequency divider . . . . . . . . . . . 35A-3 PCB for serial-controlled frequency divider . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36A-4 Schematic showing quadrature synthesis and switching . . . . . . . . . . . . . . . . . . . . . . 37A-5 P+I Temperature Control Circuit for Laser Diode and Baseplate . . . . . . . . . . . . . . . . 39A-6 Rubidum cell mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46A-7 Waveguide design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48A-8 Microwave cavity design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

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1 Introduction

Extremely high accuracy measures of time or frequency are required in many areas of scientific research.They are also essential in the maintenance of international time standards, the operation of many telecom-munications systems, and the accuracy of the GPS network. A general method of producing a very preciseand accurate frequency standard, is to lock-in a microwave resonator to the an atomic transitions of somespecies. Typically, Cesium or Rubidium are used for this purpose.

It was proposed to build an optically pumped atomic clock based on the 6.835 GHz hyperfine transitionof the 87Rb 5S1/2 ground state. Pumping is achieved through the use of a tunable laser centered on the87Rb F=2 → F’=2 hyperfine transition, which effectively spin polarizes the Rb atoms in the F=1 groundstate. A microwave is then used to complete a cyclic double resonance by re-exciting the F=1 atoms backto the F=2 state. The frequency required to engage this double resonance is known quantum mechanically,and by counting the EM oscillations this can be used to produce a highly accurate frequency standard. Thisfrequency standard was then to be compared with both quartz oscillator reference clocks and the NISTtime standard available over the GPS network. As the GPS receiver can generate time stamps accurate to√

2× 10−6s over arbitrary time scales, counting the clock frequency for 105 s would give an accuracy to onepart in 10−11, the expected limit of this technology.

It was also proposed to turn this setup upon completion into a saturated spectroscopy experiment forthe advanced physics laboratory. A higher than average budget was thus justified as the experimental setupwould be reused in future years.

2 Quantifiable Objectives

Although the overall objective of the project is to build a functioning Rubidium atomic frequency standard,and to characterize its performance, doing so requires many sub-components, each with their own set ofquantifiable goals. To construct an optically pumped atomic clock requires first locking a laser to theappropriate hyperfine transition, and then using that laser to lock the microwave system to the doubleresonance. We discuss first the performance which is required of the optical system to accomplish this task,since this serves as our objectives for this part of the experiment.

2.1 Tuneable Laser

Our goal was to design and construct a diode laser which was smoothly and approximately linearly tuneableover a range of several nanometers in wavelength about the 780nm 5S1/2-5P3/2 transition in rubidium.

2.2 Absorption Spectrum of Rubidium

The next step after constructing a tuneable laser is to resolve the doppler-broadened absorption peaks inrubidium. Since our rubidium cell is a mixture of 85Rb and 87Rb, there are four doppler-broadened peakscomprising the fine structure of the 780nm transition. It was our goal to clearly resolve each of these.

In addition to the doppler-broadened absorption peaks, we also wished to resolve the peaks’ hyperfinestructure. (Three hyperfine peaks in each doppler peak allowed by transition rules.) In particular, we wereinterested in clearly resolving the F=2 to F’=2 hyperfine peak in 87Rb, since this is the transition used forthe double resonance.

2.3 Optical Locking to Hyperfine Peak

Once the appropriate peak was resolved, our goal was to lock the laser to that peak, using a feedback loop,and to characterize the frequency range within which the lock is able to stabilize the laser.

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2.4 Double Resonance

Once the optical setup was fully working, our goal was to resolve the shape and width of both the doppler-broadened and hyperfine double resonance peaks in the microwave cavity rubidium cell, using a modulatedmicrowave signal. Once this was achieved, the goal would be to use a lock-in amplifier and a feedback loop tolock the microwave oscillator to the hyperfine double resonance peak, providing a stable frequency reference.

2.5 Frequency Stability Characterization

Once a stable clock signal was achieved, the final goal was to characterize the short term frequency stabilityand long term timing stability of the output. The goal for short term stability was to use a digital counterto make comparisons with quartz oscillators, and use those comparisons to establish the quartz oscillatorstability (approximately 1 part in 108) as the lower limit on the short term frequency stability of the clock.

For long term stability characterization, the goal was to use comparisons with the timing output of aGPS receiver to measure or set a lower limit on the long term timing stability of the clock. For the GPSreceiver we acquired provided a 1Hz pulse with 1µs jitter; hence, the maximum achievable measurementprecision is 1 part in 1012 over a counting period of one week.

2.6 Refinement of Quantitative Objectives

For the short-term stability tests, comparison to quartz oscillators should be able to establish a lower limiton (short-term) clock stability of between 10−6 and 10−8.

For the long-term stability comparisons, we may have to revise our testing schedule depending on howmuch time is available for continuous running. Measurable long term stability would then approach ∼ 10−9

In addition to frequency-stability measurements, we also intend to measure the shape and width of the6.834GHz transition in 87Rb under the double-resonance being used for the microwave frequency lock. Thetunable diode laser and saturated absorption spectroscopy setup will be used to measure the absorptionspectrum of the 87Rb and 85Rb at the sub doppler level using the saturated spectroscopy setup. The tunablelaser is expected to be tunable to below 5Mhz.

3 Theory

3.1 87Rb-beam Optically Pumped Atomic Clock

Accurate time standards can be produced by locking a crystal oscillator to an atomic transition frequency[18].For this design, a quartz crystal oscillator will be locked to the 6.835 GHz microwave transition between theF=1 and F=2 ground hyperfine levels of 87Rb. The accuracy of the time standard is related to the width ofthe microwave resonance. Due to the doppler effect, the natural resonance is broadened to 9.4 kHz. Unliketypical commercial solutions, a design is proposed which utilizes an optical pump in order to resolve thesub-doppler natural resonance and achieve order of magnitude improvements on lock accuracy.

Six optical transitions are allowed between the 52S1/2 (ground) and the 52P3/2 (1st excited) states in 87Rbfor

∆F = 0,±1 (1)

Where F is the atom’s total spin; the vector sum of nuclear and valence electron spins I + J . An opticalpumping of the F=1 ground level will be conducted (see figure 1) on the rubidium clock cell using a diodelaser tuned to the F=2→F’=2 transition using saturated absorbtion spectroscopy (see section 3.3). Drivingthe microwave cavity containing the vapor cell at the 6.835 GHz transition resonance repopulates the F=2

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ground state and thus reduces the transmission of the optical pump beam. The quartz oscillator is stabilizedto the center of the transition resonance by performing a peak lock on the absorption spectrum detected onthe photodiode resolved using a frequency shift keyed modulation of the microwave source.

Figure 1: Energy level diagram of the 87Rb-beam D2 resonance line [18]

Due to corresponding doppler shifts in the optical resonance, pumping is only achieved for atoms station-ary with respect to the beam axis in the lab frame. Similarly, the (microwave) re-pump induced opticalattenuation is only resolved for the stationary atoms. The microwave lock-in apparatus is thus less sensitiveto the atoms responsible for the doppler broadening, allowing the sharper natural linewidth to be resolvedand locked to.

3.2 Littrow Configuration Tunable Diode Laser

A large and front-end loaded part of the project is the design and construction of the tunable diode lasersystem. Fortunately, ample literature exists on the subject [4][6][8][13][16][18][23]. The design we will beusing[31] was put forward specifically with the needs of the undergraduate student in mind.

The commercially available diode laser is tuned using an external cavity Littrow configuration[5]. This isthe most basic of external tunable configuration types and is the simplest implement. The laser tunabilitydepends on the angle laser light makes with a reflective ruled grating as pictured in figure 2.

The relationship between the angles is given by the familiar grating equation:

mλ = d(sin(a) + sin(b)) (2)

To tune the laser, the incident angle of light must be adjusted such that the first order diffraction, b1

is reflected at the same angle as the incident light.This reflected light returns to the diode laser cavityand preferentially selecting the lasing mode and produces a highly monochromatic beam. Then by varyingangle of incident light, slightly different wavelengths can be reflected back to the cavity thus changing theoutput wavelength. The linearly polarized light from the zeroth order reflection is the output which isutilized for the experiment. The difficultly is stabilizing and controlling the angle of the diffraction grating.Large, nanometer scale, shifts in wavelength can be realized with the use of an optical lens mount and fine

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d

IncidentLight

DiffractedLight

ReflectedLighta

b0

b1

Figure 2: The Diffraction Grating

adjustment screws. For sub-nanometer control, a piezoelectric crystal is used to change the incident beamangle. One disadvantage of this setup is the angular change of output beam position as the wavelengthchanges. For the current experiment, it is not an issue since the piezoelectric crystal movement causes anegligible deviation of the output beam, allowing the optics to remain in fixed positions.

3.3 Saturated Absorption Spectroscopy

In order to perform an optical pumping of the F=1 ground state, the ability to selectively excite theF=2→F’=1 or F=2→F’=2 transitions of 87Rb is required, the latter of which was selected for an its increasedtransition rate resulting in increased signal strength. Laser lines, which tend to drift with temperature andmechanical fluctuations, must be centered and stabilized using feedback control. A linear laser spectroscopyis not sufficient for discriminating the hyperfine levels of the 52P3/2 state[1] as doppler-broadening limitsresolution to 520 MHz[11]. However, a doppler free saturated absorption spectroscopy can resolve thehyperfine peaks for locking.

This method splits a frequency modulated beam into three components, probe, pump and reference. Thereference beam is passed through a glass vapor cell containing thermal 87Rb and the reference spectrum isdetected on a photodetector. As the laser is swept through a transition frequency, the counter-propagatingpump and probe beam interact with stationary atoms; however as the stronger pump beam depletes theatoms in the ground state, the transmitted intensity of the probe increases. The differential probe-referencesignal yields the doppler free hyperfine absorption peaks which the laser is locked to using piezo voltagecontrol. The apparatus is pictured in figure 6.

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4 Experimental Setup

4.1 Experimental Overview

MicrowaveGenerationElectronics

MicrowaveFeedbackElectronics

OpticalFeedbackElectronics

87Rb

85Rb

Figure 3: Overview of Experimental Setup

The experimental setup utilized for this project broadly consists of two separate controlled feedbacksystems: optical and microwave. Each has the generation, detection, and feedback control systems necessaryto lock onto the required hyperfine transitions of 87Rb. The optical-frequency EM waves are generated usinga tunable laser, which is able to produce a highly coherent and stable beam. This light is then passedthrough the saturated spectroscopy optical table configuration and separated by polarization angle. Thesetup creates counter-propagating beams of asymmetric intensity through the rubidium cavity. This allowsresolution beyond the doppler-broadened absorption peak. This signal is measured using a set of photodiodes,which is used to lock the tunable laser onto the desired hyperfine transition. Alternatively, this setup canfunction in a frequency-sweeping configuration, allowing the generation of the rubidium absorption plotsshown in later sections.

The microwaves are generated using a voltage controlled quartz oscillator (VCO); the output of whichis frequency shift keyed using a direct quadrature modulator and multiplexer. Frequency sweeps of themicrowaves are carried out in the kHz range. The signal is injected into a microwave cavity, where thedouble resonance condition is detected on a photodiode monitoring the transmitted intensity of the opticalpump. This signal is read with a DSP lock-in amplifier to drive an analog circuit which stabilizes the VCOcenter frequency. To measure the VCO frequency, a 64x frequency divider is employed after which the signalis counted using a 100 MHz GPIB counter. This time signal can then be compared with that of a GPS unitwhich has been set up specifically for this project. This unit has an accuracy of

√2µs on arbitrary time

scales with respect to GPS network, synchronized to NIST time servers. Thus, a week is required to measurethe clock frequency to an accuracy of 10−11, the expected limit for the apparatus.

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Number Description1 3x0.5mm fine pitch adjustment screw (beam collimation)2 27mm diameter Piezoelectric disk3 Horizontal and Vertical Adjustable Mirror Mount4 Baseplate Thermoelectric Cooler (Hidden)5 Adjustable Lens Holder Mount6 Laser Diode Mount7 Solid Aluminum Baseplate8 Laser Diode Thermoelectric Cooler9 Diode Laser Plug10 Diode Laser11 Collimating Lens12 1200 line/mm Ruled Diffraction Grating13 Output Beam

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Figure 4: Laser Diode Components

4.2 Littrow Tunable Diode Laser

The tunable laser components are shown in figure 4. The laser diode and collimating lens are secured toaluminum blocks and then bolted to a solid aluminum baseplate. The diffraction grating is first attached toa standard mirror mount using double sided tape which is in turn bolted to the baseplate. The laser andlens are separated by a thin gap which, by way of a fine adjustment screw, allows the distance between thelens and laser to be adjusted, thus collimating the beam. Careful adjustment allows for the beam to remaincollimated to 4mm diameter over several meters. For correct operation of the laser, the first order diffractionmust be reflected precisely back to the laser diode. This is achieved by adjusting the horizontal (left) andvertical (right) knobs on the mirror mount. Once the laser is tuning approximately 1/2 turn on the horizonalknob will cause several nanometers change in wavelength. To aid with the saturated spectroscopy setup,a 36:1 gear reduction along with a flexible coupling was attached to the horizonal knob. This allows formore precise manual control which makes the task of locating the rubidium doppler-broadened absorbtionpeaks significantly easier. Very fine tunability is achieved using a piezoelectric crystal inserted between thehorizontal adjustment screw and the lens mount.

To achieve long term stability, the temperature of the laser and baseplate must be accurately controlled.Not shown on the diagram are two thermistors: one embedded immediately below the laser diode andthe second in the side of the baseplate. These are used as input into a Proportional-Integral temperaturecontroller which are used to control thermoelectric coolers, keeping the laser and baseplate stabilized slightlyunder room temperature. Finally, as the actual laser setup indicated, it is necessary to utilize large heatsinks to allow the thermoelectric coolers to dissipate the heat removed from the apparatus. (Figure 5).

4.3 Saturated Spectroscopy

4.3.1 Optics

The optics for the saturated absorption spectroscopy were designed with two chief goals in mind; achievingmaximum signal to noise, and minimizing cost. The latter proved to be a more significant constraint. Inorder to achieve the requisite counter-propagating beams, a scheme using partially silvered mirrors wouldinevitably redirect light back into the diode causing massive mode instabilities. This could be rectified using

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(a) Photograph of Laser Assembly (b) CAD Model of Laser Assembly

Figure 5: Laser diode comparison

an optical isolator, however, high cost prohibited the implementation of such a device.

Counter propagation of pump and probe beams was achieved, whilst maintaining excellent optical feedbackisolation using a suite of polarization optics depicted in figure 6. The tunable polarization rotation achievedusing a λ/2 waveplate allowed the pump:(probe+ref) intensity ratio to be tuned for optimization of theprobe signal, with the splitting achieved on polarizing beam splitter (PBS) 4. A 50:50 splitter is employedin order to separate out probe and ref beams with matched intensity, and finally feedback isolation fromvertically polarized waste pump light is achieved using PBS 7. The vapor cells selected contained naturalrubidium, approximately equal parts 85Rb and 87Rb, in order to minimize cost. This was of little concern asthe quantum signatures of the two atoms can be discriminated based on the relative spacing and strengthof their hyperfine transitions.

4.3.2 Electronics

The laser frequency was side locked to the F=2→F’=2 transition using feedback control of grating angle withthe piezo-electric transducer. A side-locking scheme was selected, as oppose to a peak-lock, as a stable opticalfrequency was required in order to perform the optical pumping (cavity cell) requisite in the cyclic-doubleresonance. This prohibited a direct modulation of the laser frequency. Down stream modulation is possibleusing either an acousto or electro-optic modulator, however, these devices were prohibitively expensive.

The optical-lock circuitry is given in Appendix B.1 and consists of 7 stages. The apparatus providesthe ability to select between two modes of operation. In sweep mode, the piezo voltage is scanned linearlyallowing the absorption spectrum to be fully resolved. During lock-in mode, a PI controller is used tostabilize the laser frequency to a position (selected during sweep mode) on the side of the selected hyperfinepeak. The position is maintained as a voltage level on the differential probe-ref output controlled via tunablesetpoint. In selecting the gains on the integral and proportional branches of the PI controller, a simulation of

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7912

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1516

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10%

90%

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Number Description1 External Cavity (Littrow Configuration) Tuned Laser2 10/90 Beam Splitter3 1

2 Waveplate4 Polarizing Beam Splitter5 Horizontally Polarized Probe Beam6 50/50 Beam Splitter7 Polarizing Beam Splitter8 Waste Pump Dump9 Natural Rubidium Vapour Cell (85Rb and 87Rb)10 Vertically Polarized Pump Beam11 Reference Beam12 Probe Photodiode13 Reference Photodiode14 Microwave Waveguide15 Microwave Cavity16 Second Natural Rubidium Vapour Cell17 Microwave Cavity Photodiode

Figure 6: Saturated Spectroscopy Setup

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the control loop was conducted using MATLAB. Gain values were selected in order provide simultaneouslyadequate stability and noise rejection over the full frequency range of the piezo (∼1kHz).

4.4 Microwave Synthesis

Once the laser is locked to the appropriate hyperfine transition, detecting and locking to the double resonancewith a microwave signal requires synthesizing and tuning a microwave signal at 6.835GHz, and coupling thatsignal into the rubidium cell. To increase signal to noise, and to produce a more stable lock-in frequency, wedecided to employ a modulated peak-locking scheme, which allows the use of a lock-in amplifier to producethe error signal for our feedback loop.

In order to modulate the microwave signal, while still retaining a stable center frequency for the clockoutput, we used a voltage controlled oscillator (VCO) connected through an I/Q Mixer, which acts as amodulator. This provides both a stable center frequency directly from the VCO, as well as signal modulatedabout that frequency from the I/Q Mixer. For the purpose of obtaining an accurately centered lock onthe peak, frequency-modulation with an I/Q mixer requires amplitude matched sine waves in quadrature(90 degrees out of phase), at a desired modulation frequency representing lock location on the peak. Thisfrequency source was supplied with a quadrature oscillator circuit. The overall configuration is shown inFigure 7.

I Q

DSP Lock-In Amplifier

Photodiode Signal

Ref

Signal Generator

(100kHz Square Wave)

Sel

PI Control

Frequency Divider

Output Clock Signal (f/64)

Figure 7: Microwave synthesis and feedback chain.

4.4.1 Quadrature Oscillator

In order to produce two signals in tight quadrature at identical amplitudes, a dual op-amp integrator oscillatorwas used (See Figure A-4). These integrators set two poles at the desired 1/RC oscillation frequency, causing

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oscillations as the loop gain crosses the zero gain point. This setup is used to stabilize a RC oscillator whileproducing a complementary signal. The transfer function of this oscillator can be represented as shown inEquation 3.

Aβ =(

1R1C1s

) (R3C3s + 1

R3C3s(R2C2s + 1)

)(3)

In the case where R1C1 = R2C2 = R3C3, this transfer function can be reduced to Equation 4.

Aβ =1

(RCs)2(4)

The oscillation frequency is tuneable through simultaneous adjustment of the three 24-turn trim potentiome-ters, following the relation of Equation 4, while fine tuning of the individual signals is provided throughadjustment of the the potentiometer for the respective integrator. Any output distortion was too low to benoticeable over our range of operating frequencies; the bandwidth of the voltage feedback op-amps utilizedin this design theoretically introduces large phase error as oscillation frequency approaches a few hundredkilohertz. This is much less of a potential problem due to the high degree of tuneability of each separatecircuit section.

4.4.2 Multiplexer

The output from the quadrature oscillator is fed into an analog multiplexer, connected to the I/Q inputs ofthe mixer. This multiplexer allows switching which I/Q input is leading and which is lagging, in order toprovide frequency modulation in either phase direction. The select inputs of the multiplexer are driven witha square wave, alternating the phase of the input to the I/Q mixer. This frequency modulated signal is thendelivered into the microwave cavity.

4.4.3 Waveguide

In order to cheaply and efficiently couple this microwave signal into the cavity, a simple waveguide and stubantenna are used. A simulation of this waveguide using NEC2 software (Numerical Electromagnetics Code)provides insight into the performance of the antenna and waveguide combination; Figure 4.4.3 shows thisdesign does result in gain, and the signal will be coupled into the cavity.

4.4.4 Feedback

Since the modulation of the microwaves is driven by the quadrature output switching by the multiplexor,the multiplexor clock provides a natural reference signal for lock-in amplification. The signal from themicrowave-cavity photodiode is fed to the lock-in amplifier using this clock as a reference. Since the doubleresonance peak is symmetric, we expect modulation to drive a non-zero lock-in signal when off-center, withthe signal approaching zero as the center frequency of the microwave modulation approaches the peak center.This is shown schematically in Figure 9.

The lock-in output is therefore used as the error signal for a Proportional-Integral feedback loop whichcontrols the VCO voltage and therefore the center frequency of the modulation and the output frequency ofthe clock. A schematic circuit diagram of the feedback circuit is shown in Figure 10.

4.4.5 Frequency Division

Although the output of the clock is at 6.835GHz, the digital counter at our disposal is only capable ofcounting signals up to 120MHz. We have selected a VCO with an f/2 frequency divided output in additionto the main output, however, additional frequency division is still required to produce a countable signal.We accomplish this with the frequency counter/divider built into certain PLL IC’s. Printed circuit boardshave been fabricated for two such IC’s, shown in Figures A-2 and A-3.

15

Figure 8: Electromagnetic Simulation of waveguide antenna

fc

fc + foff

fc − foff

Feedback

Figure 9: Illustration of microwave modulation about a center frequency on the double resonance peak.

AdderBias Voltage

≈4V

Integrator

Inverting Amp

Verr(from lock-in

Output)

Vout(VCO Control

Voltage)

Figure 10: Schematic circuit diagram of the microwave feedback circuit.

16

4.5 Frequency/Timing Stability Characterization

In designing what is meant to be a time/frequency standard, we also required a method for characterizingthe short and long term stability of the clock output in terms of frequency jitter/drift. Since measuringfrequency directly with an external device inherently ties the measurement to the internal oscillator of thatdevice, in order to cleanly measure our output, we rely on counting signal cycles using a digital counter,except when directly comparing the clock output to an external oscillator. To this end, we use a 120MHzdigital counter, with external reference and external gating capabilities. The configuration for characterizinglong-term stability uses a GPS receiver as a time reference.

4.5.1 Short Term Frequency Stability

To characterize the short term frequency stability of the clock, we measure the jitter in comparisons betweenpairs of oscillators, including the clock. The basis behind this is that the absolute frequency jitter from twoindependent oscillators adds in quadrature when making a frequency comparison between the oscillators.This frequency comparison is made by using one oscillator as the counter reference to measure the frequencyof the second oscillator. The configuration is shown in Figure 11

Figure 11: Instrumentation setup for characterizing short term stability of the clock. Comparison is madewith a 10Mhz quartz oscillator. This same configuration can also be used for comparing relative frequencystability of two quartz oscillators.

This configuration is convenient, because several of the instruments we are using for other purposes alsoprovide a 10MHz reference output from their internal quartz oscillators.

This configuration in principle allows us to set a lower limit on the short term stability of the clock output.The first step would be to compare the clock output to several quartz oscillators. Next, the quartz oscillatorsare compared with each other. If the clock-quartz oscillator jitter is measureably smaller than the quartz-quartz comparisons, then this establishes the quartz oscillator stability (estimated from the quartz-quartzcomparisons) as a lower limit on the short term stability of the clock frequency output.

17

4.5.2 Long Term Timing Stability

Characterizing the long-term stability of the clock output presents additional challenges, since it requiresan extremely stable time reference. This is provided by a GPS receiver, which provides a 1Hz timing pulsesynchronized to the GPS network timing (Which is in turn based on reference atomic clocks). In order toobtain consistent GPS reception, the GPS receiver has been mounted outside of the building near the lab,and an extension cable has been made and routed through through the basement ceiling. The receiver hasa strong and consistent signal, verified by the computer interface over many weeks. The 1Hz timing outputhas been configured and tested, as well as used to gate the digital counter.

Figure 12: Testing GPS reception in outdoor mounting location.

The manufacturer’s specifications for the GPS receiver state a jitter of ±1 µs for the rising edge of the1Hz pulses from the GPS receiver (This has been verified in the lab with comparisons to quartz oscillators.)Since this pulse is disciplined to the GPS network timing, however, this error is not cumulative. Thismeans that with the GPS receiver gating the counter (as shown in Figure 13), counts can be obtained overarbitrary timescales with an absolute uncertainty in measurement time of

√2 µs. Measurement precision is

then determined by how long the clock is run for. For example, running the clock for a week would providean uncertainty of

√2 µs over a total interval of 604,800 s, or roughly one part in 1012.

4.6 Microwave Cavity and Waveguide

In order to measure the double resonance in the rubidium cell, a microwave cavity, waveguide and mountwere built.

The microwave cavity design is shown in Figure A-8. A multimode cavity was used to produce a flatdistribution of microwave intensity. The waveguide design is shown in Figure A-7. A hole was drilled inthe end of the waveguide for the laser beam to enter. A mount for the rubidium cell inside the cavity wascreated in CAD software and then printed on the rapid prototyping machine at Beamish-Monroe Hall. The

18

Figure 13: Instrumentation setup for characterizing long term stability of the clock. Comparison is madeover a long time scale with the 1Hz reference pulse from a GPS receiver.

design can be found in Figure A-6. This was done to avoid the use of metal, which would reflect microwaves.The mount was made out of ABS plastic.

The coupling efficiency of the electronics system to the microwave resonator was evaluated. Unmodulated,6.8 GHz frequency was first pumped directly into a high-frequency rectifying diode, and then indirectlythrough the pump antenna, waveguide, and a 1/4 wavelength pick-up antenna inserted into the cavity. Therelative transmission loss in the latter case was approximately 1000 times greater. The absolute efficiency, inthis case, is not the relevant parameter, as the pick-up antenna receives only a fraction of the microwave powerin the cavity; however, more importantly, the functionality of the microwave chain has been demonstrated.

19

5 Results

5.1 Tunable Laser

The tunable laser system was characterized according to its various degrees of freedom. Originally, it wasintended that gain curves for lasing current, diode temperature, and grating angle would be produced onthe Ocean Optics spectrometer in the 5th floor labs. Unfortunately, it was found that the resolution of thespectrometer was prohibitively low for all but the grating angle. It was confirmed during the subsequenttests on our optical table that the laser was indeed sensitive to these other parameters. Each degree offreedom on the tunable laser is now be discussed in detail.

5.1.1 Angle Dependence of Lasing Wavelength

From the outset it was expected that the most coarse adjustment of the lasing wavelength would be achievedusing the grating angle. Using the installed 36:1 microdrive, the wavelength response to an angular change ofthe tuning knob was investigated on the Ocean Optics Spectrometer. It was found that the lasing wavelengthvaried on the order of nanometers, which were readily observable. A series of beam profiles were recordedfor various tuning knob positions, and are shown in Figure 14. Though the figure shows a wavelength shiftof approximately 5 nm, it was found that the laser could tune up to 8 nm, centered around approximately782 nm.

775 780 785 790 795 8000

0.05

0.1

0.15

0.2

0.25

Wavelength, (nm)

Inte

nsity

(norm

alize

d)

0 Degrees

Fit: Ae−

(λ−λ0)2

(2σ)2

A = (1.6 ± 0.1) × 10−1

λ0 = (7.7719 ± 0.0005) × 102

σ = (6.2 ± 0.3) × 10−1

Reduced χ2 = 0.004413.45 Degrees

Fit: Ae−

(λ−λ0)2

(2σ)2

A = (1.64 ± 0.04) × 10−1

λ0 = (7.7936 ± 0.0001) × 102

σ = (6.33 ± 0.08) × 10−1

Reduced χ2 = 0.000272.90 Degrees

Fit: Ae−

(λ−λ0)2

(2σ)2

A = (1.55 ± 0.03) × 10−1

λ0 = (7.8139 ± 0.0001) × 102

σ = (7.11 ± 0.09) × 10−1

Reduced χ2 = 0.000278.

Figure 14: Gaussian Beam Profiles at Various Tuning Knob Angles

It was expected that the lasing wavelength shift would be linear with the incident grating angle change,and this was examined in Figure 15. The relationship was roughly linear, though large errors are seen on theresulting data. This is due to a number of factors. Firstly, the spectrometer is not able to resolve beyond

20

−40 −30 −20 −10 0 10 20 30 40779.5

780

780.5

781

781.5

782

Knob θ (degrees)

Cen

ter

Wavel

ength

(nm

)

Observed Data

Fit: Aθ + λ0

A = (2.7 ± 0.4)× 10−2

λ0 = (7.8063 ± 0.0007)× 102

Reduced χ2 = 22.239095.

Figure 15: Tuning with Knob Angle

its bin width, which for this calibration was on the order of 0.3 nm. The error in the resulting gaussian fitsmust thus be added in quadrature with this value, which dominates the final error. Secondly, the installedmicrodrive does not completely transfer motion to the tuning knob. Some gear slop is present for every turnon the microdrive, adding a systemic error to the suspected angular shift. There might also be slack on thescrew into the lens mount being used to actually move the grating. For these reasons, the group was satisfiedwith the observed linearity and moved on for lack of better testing equipment.

5.1.2 Temperature Stabilization

0 5 10 15 201.8

1.85

1.9

1.95

2

2.05

2.1

2.15

2.2

2.25

2.3

! " #$

% !&

')(+*-,/.1032-415 6)7+8-9:7+;<')(+*-,/. =?>@A5 B19:7+;<')(+*-,/. C?D @ 5 B19:7+;<

Figure 16: Step Response of Temperature Controller

A pair of PI temperature controllers were designed and employed on the tunable laser housing to providethe desired stability in the long term. Temperatures were measured in arbitrary voltage units using twothermistors. Once a setpoint was decided upon, it was expected that turning on the temperature controllers

21

would quickly bring the temperature down to the setpoint with minimal oscillations. This process is shownduring different days in Figure 16. The proportional and integral gains were tuned empirically, and theresults are evident from the plot. Full temperature stabilization required approximately 10 minutes andpersisted for arbitrarily long time scales.

5.1.3 Constant Current Driver Performance

10 20 30 40 50 60 7075

75.01

75.02

75.03

75.04

75.05

75.06

75.07

Time (min)

Lase

rC

urr

ent

(mA

)

Figure 17: Lasing Current in Constant Current Mode

The constant current controller, purchased from Thor Labs, was also characterized over a long time scale.During the experiment, it was found that the current controller did not perform as expected; and long termdrifts of the current were seen. The power supplies to the controller were replaced in favor of dedicatedsupplies, which greatly improved stability. However, some drift was still present on the order of tens of µA,shown in Figure 17. Though small, this drift was enough to be observed on the saturated spectroscopy setup.The source of these drifts at this time are uncertain, though they most likely lie in the internal circuitry ofthe Thor Labs PCB. Our group had intended on re-designing and remaking this part, were there more timefor this project.

Overall, the diode laser performed adequately and was capable of fulfilling its role in the rest of theatomic clock setup.

22

5.2 Saturated Spectroscopy of Rubidium

The saturated absorption spectroscopy performed remarkably well. The hyperfine absorption peaks, 6 al-lowed for each 85Rb and 87Rb, were resolved more clearly than seen in the published literature [27]. Figures18 and 19 depict the probe and differential satspec signals recorded when performing linear sweeps in thelaser frequency. The former shows the hyperfine peaks superimposed on the doppler broadened spectrum.The differential signal, used for the lock circuitry, is the analog subtraction of the probe and reference signals.The frequency axis was scaled in figure 18 using literature values the 87Rb hyperfine energy levels.

−2000 −1500 −1000 −500 0 500 1000 1500 2000−0.5

−0.4

−0.3

−0.2

−0.1

0

0.1

0.2

0.3

0.4

0.5Hyperfine peaks for 85

Rb (F=3) and 87Rb (F=2)

∆ F (MHz)

Voltage

(V)

Probe signalDoppler-subtracted hyperfine peaks

Figure 18: Hyperfine peaks of natural rubidium. Right 85Rb F=3→F’ transitions. Left 87Rb F=2→F’transitions. The 87Rb F=2→F’=2 transition, centered at 0 MHz, is locked to during clock operation.

23

−7 −6 −5 −4 −3 −2 −1 0 1 2 3 4

x 10−3

−1

−0.5

0

0.5

1

1.5

Frequency (Arb)

Voltage

(Arb

)

Probe Signal

Doppler-subtracted hyperfine peaks

Figure 19: Hyperfine peaks of natural rubidium. Left 87Rb F=1→F’ transitions. Right 85Rb F=2→F’transitions.

The peak centroids were determined using a Lorentzian fitting routine. The theoretical Lorentzian lineshape modeled the hyperfine resonance peaks well (see figure 20) but for the asymmetry in the floor attributedto imperfect balance of the probe and ref signal amplitudes.

The optical lock performed satisfactorily and stabilized the laser frequency for upwards of 1 hour. Due tothe nature of the side-lock, overstepping the peak would result in a permanent loss of lock which would needto be manually reset. As a result, a loss of lock would occur if sufficient amplitude acoustic vibrations, outsidethe loop bandwidth, were introduced into the system. However, the PI controller adequately countered lowerfrequency noise sources such as drifts in temperature and laser current as desired.

24

−1000 −500 0 500 1000−0.04

−0.02

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16Hyperfine F=2 peaks for 87

Rb

∆ F (MHz)

Voltage

(V)

Doppler-subtracted hyperfine peaksLorentz Fit

Figure 20: Lorentzian fitted 87Rb F=2→F’ transitions. From left to right F’=1,2,3.

25

−10 −8 −6 −4 −2 0 2

x 10−3

0.08

0.1

0.12

0.14

0.16

0.18

0.2

0.22

0.24Optical Lock Confirmation

Photo

dio

de

Voltage

(V)

Time (s)

Figure 21: The effect of acoustic noise on the optical lock circuit. The satspec differential signal is shown tooscillate outside the lock bandwidth at ∼1.2kHz

26

GK CPS JF DS DB JBDTunable Laser Design X X

Tunable Laser Construction X XTunable Laser Calibration X X

Cavity and Waveguide Design X X X XCavity and Waveguide Construction X

Saturated Spectroscopy Design XSaturated Spectroscopy Alignment X X X

Data Acquisition System XGPS Time Stamp System X

Optical Feedback Circuit Design X XMicrowave Generation Circuit Design X X X

Microwave Feedback Circuit Design X X X

Table 1: Division of Labour Chart

6 Responsibilities and Timeline

6.1 Organization of Team Activities

The current activities being undertaken by the team is repeated in Table 1, along with an indication of whois responsible for each task. It should be noted that this list is not exhaustive, as completed items have beenexcluded.

6.2 Gantt Chart

A gantt chart is included to summarize the progression through the project during, before, and after thealloted 12 weeks. Generally, our group put in a solid effort throughout the entire period except for the shortrespite to complete our thesis projects.

27

ID Task Name Start

1 Project Topic Decision Fri 10/11/06

2 Project Proposal Mon 20/11/06

3 Procurment of necessary parts Mon 18/12/06

4 Christmas Holidays Fri 22/12/06

5 Grating Stablized Tuned Laser Design Tue 12/12/06

6 Tuned Laser Construction Thu 11/01/07

7 Tuned Laser Testing & Calibration Tue 27/02/07

8 Microwave Cavity Design Tue 16/01/07

9 Microwave Cavity Construction Tue 23/01/07

10 Reading (Thesis) Week Tue 13/02/07

11 Rubidium Vapour Cell Design Tue 27/02/07

12 Optical Setup Tue 20/03/07

13 Sa Spectroscopy Measurements Tue 27/03/07

14 Microwave Synthesizer Operation Thu 29/03/07

15 Cavity Feedback Control Thu 19/04/07

16 Complete System Debugging Tue 03/04/07

17 Timing Measurements Fri 20/04/07

Carlos Paz-Soldan,David Burns,Devon Stopps,Gaetan Kenway,Joseph Fox,Joshua Bendavid

Dirk and Bernie

Carlos Paz-Soldan[15%],David Burns[15%],Gaetan Kenway[15%]

Carlos Paz-Soldan[50%],Gaetan Kenway[50%]

Carlos Paz-Soldan[50%],Gaetan Kenway[50%]

Devon Stopps[50%],Joshua Bendavid[50%]

Joseph Fox

Joseph Fox[15%],Joshua Bendavid[15%]

David Burns[50%],Carlos Paz-Soldan[15%],Gaetan Kenway[15%]

David Burns[15%],Joshua Bendavid[15%],Carlos

Joshua Bendavid,Joseph Fox

Devon Stopps

Carlos Paz-Soldan,David Burns,Devon Stopps,Gaetan

Carlos Paz-Soldan,David Burns,Devon Stopps,Gaet

29 05 12 19 26 03 10 17 24 31 07 14 21 28 04 11 18 25 04 11 18 25 01 08 15 22 29 06 13 20 27 03 10 17 24 01 08 15 22 29 05 12 19 26 02 09Nov '06 Dec '06 Jan '07 Feb '07 Mar '07 Apr '07 May '07 Jun '07 Jul '07 Aug '07 Sep '

Page 1

Figure 22: Gantt Chart for Atomic Clock Project

7 Safety

The tunable diode laser emits a 10-30mW beam at 780 nm. This is very harmful to the unshielded eye.As such, specialty laser goggles were purchased for use when calibrating and operating the diode laser. Anenclosure box was also created to house the completed optical table, allowing multiple people access tothe laboratory without the need of limited laser goggles. Prior to this, only people wearing goggles werebe allowed near the operating laser system, which limited the number of people working on the projectsimultaneously.

As a matter of minor concern, natural rubidium reacts aggressively with normal skin and care would havebeen taken been taken to avoid its vapour state were it to have escaped from its glass housing. Microwavescan also be harmful, though at the power levels used in this experiment, it was not seen to pose a majorproblem.

28

8 Conclusion

A design proposal was made for an optically pumped atomic clock utilizing the hyperfine transitions of87Rb. A double-resonance condition was conceived using a parallel optical and microwave chain to locka microwave oscillator to the sub-doppler resonance. For the optical chain, a tunable laser was built anddemonstrated to reliably tune over the required transitions of 87Rb. This was detected using a saturatedspectroscopy setup. An analog feedback circuit was created which was able to lock the laser frequency tothe 87Rb F=2 → F’=2 transition. Using this same setup, the tunable laser was used to characterize the5S1/2 →P3/2 state transitions of both 87Rb & 85Rb. A microwave generation and modulation chain wasdesigned and built, though at the time of writing the double resonance condition has yet to be observed.This was due to inadequate time for testing. A frequency divider was designed to allow the microwave signalto be counted, though it was not functioning at the time of writing. The most difficult parts of the projecthave been demonstrated to reliably function, fulfilling the majority of the project objectives.

9 Group Statement

From the outset it was known that this project was going to be ambitious and challenging. Though atomicclocks have existed for many decades, the diode laser technology required to make this project possible on amodest budget has only been developed in the last decade. Many components had to be innovatively designedto function within our budgetary constraints, and as a result we are confident that we have achieved goodtrade off between scientific value and monetary expenditures. Specifically, our microwave generation setupis completely of our own design, as is the particular setup utilized for the saturated spectroscopy technique.

The final timing results were not complete in time for this report, due to setbacks in the microwavegeneration and detection chain. The PCB containing much of the microwave chain was completed far laterthan expected, resulting in very little time for debugging. At the time of writing, the frequency dividerPCB was non-functional, and this delayed the entire microwave chain. We are confident that the generationis working, though it is very difficult to detect the double resonance without an accurate knowledge of thefrequencies being injected into the microwave cavity. As we have entered this project into an IEEE designcompetition, we intend to resume our effort on these last components upon completion of our report andexams.

Despite the setbacks, many of our key objectives have been met. A functional saturated spectroscopysetup has been created, allowing for the apparatus to be utilized in a PHYS 450 lab.

References

[1] Diode laser spectroscopy. Teachspin. Available at http://www.teachspin.com/instruments/diode_laser/index.shtml.

[2] Introduction to quartz frequency standards - oscillator comparison and selection. IEEE Ultrasonics,Ferroelectrics, and Frequency Control Society. http://www.ieee-uffc.org/freqcontrol/quartz/vig/vigcomp.htm.

[3] The ntp faq and howto: Understanding and using the network time protocol. NTP Project. http://www.ntp.org/ntpfaq/NTP-s-algo.htm.

[4] C. Affolderbach, F. Droz, and G. Mileti. Experimental demonstration of a compact and high-performance laser-pumped rubidium gas cell atomic frequency standard. IEEE Transsactions on In-strumentation and Measurement, 55(2):429–435, April 2006.

29

[5] A. S. Arnold, J. S. Wilson, and M. G. Boshier. A simple extended-cavity diode laser. Review of ScientificInstruments, 69(3):1236–1239, March 1998.

[6] J. C. Bergquist, M. Feldman, L. L. Lewis, and F. L. Walls. Preliminary invesitgation of a new opticallypumped atomic rubidium standard. In 35th Ann. Freq. Control Symposium, pages 612–624, May 1981.

[7] M. Breton, N. Cyr, C. Julien, C. Latrasse, M. Tetu, and P. Tremblay. Optically pumped rubidium as afrequency standard at 196 thz. IEEE Transsactions on Instrumentation and Measurement, 44(2):162–165, April 1995.

[8] M. Breton, N. Cyr, M. Tetu, S. Thriault, P. Tremblay, and B. Villeneuve. Toward the realization ofa wavelength standard at 780 nm based on a laser diode frequency locked to rubidium vapor. IEEETranssactions on Instrumentation and Measurement, 40(2):191–195, April 1991.

[9] G. Brida, A. Godone, F. Levi, and C. Novero. Analysis of the light shift effect in the 87rb frequencystandard. IEEE Transsactions on Instrumentation and Measurement, 46(2):126–129, April 1997.

[10] C. E. Calosso, A. Godone, F. Levi, and S. Micallzio. The pulsed rubidium clock. IEEE Transsactionson Ultrasonics, Ferrorelectrics and Frequency Control, 53(3):525–529, March 2006.

[11] K. L. Corwin, Z.-T. Lu, C. F. Hand, R. J. Epstein, and C. E. Wieman. Frequency-stabilized diode laserwith the zeeman shift in an atomic vapor. Optical Society of America, 1998.

[12] R. Cushing. Single sideband upconversion of quadrature dds signals to the 800-2500mhz band., 2000.Analog Dialog 34-3.

[13] J. Deng, R. E. Drullinger, D. A. Jennings, G. Mileti, and F. L. Walls. Laser-pumped rubidium fre-quency standards: News analysis and progress. IEEE Journal of Quantum Electronics, 34(2):233–237,September 1998.

[14] DeSerio. Saturated absorption addendum.

[15] G. J. Dick, L. Maleki, and J. D. Prestage. Linear ion trap based atomic frequency standard. IEEETranssactions on Instrumentation and Measurement, 40(2):132–136, April 1991.

[16] M. Feldman and L. L. Lewis. Optical pumping by lasers in atomic frequency standards. In 35th Ann.Freq. Control Symposium, pages 612–624, May 1981.

[17] R. W. Fox, C. S. Weimer, L. Hollberg, and G. C. Turk. The diode laser as a spectroscopic tool.Specrochmica Acta, 15(5):291–298, 1993.

[18] H. Furuta, K. Nakagawa, and M. Ohtsu. Diode laser-pumped rb-beam atomic clock as a novel primaryfrequency standard. Graduate School at Nagatusta, Tokyo Institute of Technology 4259 Nagatsuta,Midori-ku, Yokohama Kanagawa 227, Japan.

[19] H. Furuta and M. Ohtsu. Estimation of frequency accuracy and stability in a diode laser-pumpedrubidium beam atomic clock using a novel microwave resonant method. Japanese Journal of AppliedPhysics, 30(11A):2921–2931, August 1991.

[20] Garmin. Gps 18 oem specifications. http://www.garmin.com/products/gps18oem/spec.html.

[21] A. Hallin. Conversation in lab, November 2006.

[22] M. L. Harris, C. S. Adams, S. L. Cornish, I. C. McLeod, E. Tarleton, and I. G. Hughes. Polarizationspectroscopy in rubidium and cesium. Physical Review, 73(062509), 2006.

[23] M. Hashimoto and M. Ohtsu. Experiments on a semiconductor laser pumped rubidium atomic clock.IEEE Journal of Quantum Electronics, 23(4):446–451, April 1987.

30

[24] C. J. Hawthorn, K. P. Weber, and R. E. Scholten. Littrow configuration tunable external cavity diodelaser with fixed direction output beam. Review of Scientific Instruments, 72(12):4477–4479, December2001.

[25] A. Hirai, T. Ogawa, I. Takahashi, and M. Takeyama. Stark modulation atomic clock. Review of ScientificInstruments, 27(9):739–745, Septemeber 1956.

[26] A. Kaplan, M. F. Andersen, T. Grunzweig, and N. Davidson. Hyperfine spectroscopy of opticallytrapped atoms. Journal of Optics: Quantum and Semiclassical Optics.

[27] S. Kraft, A. Deninger, C. Truck, J. Fortagh, F. Lison, and C. Zimmermann. Rubidium spectroscopy at778-780 nm with a distributed feedback laser diode. Laser Physics Letters, pages 1–6, November 2004.

[28] L. C. Kristan, C. F. H. Zang-Tian Lu, R. J. Epstein, and C. E. Wieman.

[29] N. Kuramochi, M. Ohtsu, N. Oura, T. Tako, and H. Tsuchida. Frequency stabilization of algaassemiconductor laser based on the 85rb − d2 line. Japanese Journal of Applied Physics, 21(9):561–563,September 1982.

[30] R. LaRosa, T. J. Marynowski, and K. J. Henrich. A simple modulator for sinusoidal frequency shiftkeying. IEEE Transactions on Communications, 30(5):1048–1051, May 1982.

[31] K. B. MacAdam, A. Steinbach, and C. Wieman. A narrow-band tunable diode laser system with gratingfeedback, and a saturated absorption spectrometer for cs and rb. In Joint Institute for LaboratoryAstrophysics and the Department of Physics, University of Colorado Boulder, Colorado 80309-0440,pages 1098–1111. American Association of Physics Teachers, June 1992.

[32] A. J. Olson, E. J. Carlson, and S. K. Mayer. Two-photon spectroscopy of rubidium using a grating-feedback diode laser. Dept. of Chem. and Physics, University of Portland, 69(3):1236–1239, March1998.

[33] L. Reza. Constuction of an external cavity diode laser for use in frequency modulation spectroscopywith an electro-optic phase modulator. U. of Colorado at Boulder, 2006.

[34] A. Risley, J. S. Jarvis, and J. Vanier. The dependence of frequency upon microwave power of wall-coatedand buffer-gas-filled gas cell rb[sup 87] frequency standards. Journal of Applied Physics, 51(9):4571–4576, 1980. http://link.aip.org/link/?JAP/51/4571/1.

[35] C. E. Wieman and L. Hollberg. Using diode lasers for atomic physics. Scientific Instruemntation,62(1):1–20, January 1991.

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A Purchased Parts List

Part Quan Part Num Supplier Unit Price TotalLaser Diode 785nm, 50mw 1 HL7851G Thor labs $83.33 $83.33

1200 l/mm Diffraction Grating 1 GR13-1208 Thor labs $67.00 $67.00Thermoelectric Cooler 1 tec3-2.5 Thor labs $28.75 $28.75

Fine Adjustment Screw 1 f3ss12 Thor labs $8.00 $8.00Threaded Bushing 1 f3ssn1 Thor labs $6.00 $6.00Collimating Lens 1 c230tm-b Thor labs $86.00 $86.00

Photodiode 3 fds1010 Thor labs $41.25 $123.75Piezo Disk 5 587-1423-ND Mouser Elec. $1.04 $5.20

GPS receiver (Garmin) 1 GPS18LVC GPSCity $79.95 $79.95250mW laser driver 1 LD1255 Thor labs $119.00 $119.00

Multiplexer 1 AD8182ARZ DigiKey $6.75 $6.75Voltage Controleld Oscillator 1 HMC507 Hittite Sample $0.00

I/Q Rejection Mixer 1 HMC525LC4 Hittite Sample $0.00Laser Diode Holder 1 S8060 Thor Labs $5.49 $5.49

Rubidium Vapour Cell 2 CP25075-RB Thor labs $395.00 $790.00Polarizing Beam Splitter 2 PSCL-4-NIR OFR $210.00 $420.00

Half Wave Plate (retarder) 1 RM--780 OFR $210.00 $210.00IC Op Amps 5 AD8027ARZ-ND Digikey $3.73 $18.65

IC Divider / PLL Synthesizer 1 ADF4007BCPZ-ND DigiKey $6.01 $6.01IC Synth Freq PLL 7GHz 1 ADF4107BRUZ-ND DigiKey $6.63 $6.63

SMA Jacks 3 ACX1230-ND DigiKey $5.71 $17.13Ceramic RF Capacitors 10 478-3658-1-ND DigiKey $1.04 $10.40

Printed Circuit Board 1 N/A ILC Shop $41.05 $41.05Cavity Rubidium Cell Mount 1 N/A ILC Shop $42.00 $42.00

Laser Glasses 2 PLS-07 SG USA $118.00 $118.00

Subtotal $2,299.09Taxes $344.86Total $2,643.95

Table A-1: List of purchased components for the experiment

32

B Circuit Schematics

B.1 Optical Lock

Title

Designed by

Revision Page 1 of 1 Figure A-1: Satspec optical side-lock circuitry schematic

1. Power Supply Stage for ref and probe diodes

2. Bessel low pass Sallen Key filter. Chosen for flat phase response, buffering, and high frequency noiserejection.

33

3. Differential amplifier for probe-ref subtraction. Includes single branch tunable gain for amplitudebalancing.

4. Second differential amplifier; produces the error signal as the difference between differential output andsetpoint.

5. Integral branch of control loop

6. Proportional branch of control loop

7. Adder and high voltage gain stage. Produces the piezo control signal as the sum of the piezo setpointand either the signal generator output for performing frequency sweeps or the lock feedback duringoperation.

34

B.2 PCB

Figure A-2: PCB top section is quadrature oscillator, bottom is high frequency divider

35

Figure A-3: PCB for serial-controlled frequency divider

36

U6 AD8

014A

R32

4 7

6

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C6 15pF

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U5 SMA

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Figure A-4: Schematic showing quadrature synthesis and switching

37

B.3 Temperature Controller

38

¡¡¡¡¡¡¡ .mine

Title

Designed by

Revision Page 1 of 1

=======

Title

Designed by

Revision Page 1 of 1

¿¿¿¿¿¿¿ .r494

Figure A-5: P+I Temperature Control Circuit for Laser Diode and Baseplate

39

C CAD Drawings

The following pages present the engineering drawings which were used during the manufacture of customcomponents for the project.

40

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Figure A-6: Rubidum cell mount

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Figure A-8: Microwave cavity design

50

D Sample Code

The following pages present some of the various MatLab and Maple code utilized for design and dataanalysis.

51

09/04/07 11:13 PM C:\Documents and Settings\Carlos\My ...\caliblaserknobdegree2.m 1 of 3

%This can be used to generate plots of the laserclear allclose all knoboutfile='eplots/knobcalib2-10apr.eps' %----------------------- infile='data/-3.Master.sample.txt'data=dlmread(infile)lambdas = data(:,1)tempcounts = data(:,2)sums=sum(tempcounts(1750:1850))counts=tempcounts/sumsfitfun=@(A,lambda) A(1).*exp(-(lambda-A(2)).^2/(2.*A(3).^2))dcounts=abs((counts)).^(1/2)w=abs(1./(counts+1))startvals=[0.2,780,2][peakfit,peakfitvalues,peakfitsigmas,rchi2]=advancedfit(fitfun,startvals,lambdas,counts,w)Degs(1)WaveL(1)=peakfitvalues(2)WaveLsigma(1)=peakfitsigmas(2) %-----------------------------------------%-----------------------------------------infile='data/-2.Master.sample.txt'data=dlmread(infile)lambdas = data(:,1)tempcounts = data(:,2)sums=sum(tempcounts(1750:1850))counts=tempcounts/sumsfitfun=@(A,lambda) A(1).*exp(-(lambda-A(2)).^2/(2.*A(3).^2))dcounts=abs((counts)).^(1/2)w=abs(1./(counts+1))startvals=[0.2,780,2][peakfit,peakfitvalues,peakfitsigmas,rchi2]=advancedfit(fitfun,startvals,lambdas,counts,w)Degs(2)WaveL(2)=peakfitvalues(2)WaveLsigma(2)=peakfitsigmas(2)%--------------------------------------------- %-----------------------------------------infile='data/-1.Master.sample.txt'data=dlmread(infile)lambdas = data(:,1)tempcounts = data(:,2)sums=sum(tempcounts(1750:1850))counts=tempcounts/sumsfitfun=@(A,lambda) A(1).*exp(-(lambda-A(2)).^2/(2.*A(3).^2))dcounts=abs((counts)).^(1/2)w=abs(1./(counts+1))

09/04/07 11:13 PM C:\Documents and Settings\Carlos\My ...\caliblaserknobdegree2.m 2 of 3

startvals=[0.2,780,2][peakfit,peakfitvalues,peakfitsigmas,rchi2]=advancedfit(fitfun,startvals,lambdas,counts,w)Degs(3)WaveL(3)=peakfitvalues(2)WaveLsigma(3)=peakfitsigmas(2) %-----------------------------------------infile='data/0.Master.sample.txt'data=dlmread(infile)lambdas = data(:,1)tempcounts = data(:,2)sums=sum(tempcounts(1750:1850))counts=tempcounts/sumsfitfun=@(A,lambda) A(1).*exp(-(lambda-A(2)).^2/(2.*A(3).^2))dcounts=abs((counts)).^(1/2)w=abs(1./(counts+1))startvals=[0.2,780,2][peakfit,peakfitvalues,peakfitsigmas,rchi2]=advancedfit(fitfun,startvals,lambdas,counts,w)Degs(4)WaveL(4)=peakfitvalues(2)WaveLsigma(4)=peakfitsigmas(2) %-----------------------------------------infile='data/1.Master.sample.txt'data=dlmread(infile)lambdas = data(:,1)tempcounts = data(:,2)sums=sum(tempcounts(1750:1850))counts=tempcounts/sumsfitfun=@(A,lambda) A(1).*exp(-(lambda-A(2)).^2/(2.*A(3).^2))dcounts=abs((counts)).^(1/2)w=abs(1./(counts+1))startvals=[0.2,780,2][peakfit,peakfitvalues,peakfitsigmas,rchi2]=advancedfit(fitfun,startvals,lambdas,counts,w)Degs(5)WaveL(5)=peakfitvalues(2)WaveLsigma(5)=peakfitsigmas(2)%%%%------------- infile='data/2.Master.sample.txt'data=dlmread(infile)lambdas = data(:,1)tempcounts = data(:,2)sums=sum(tempcounts(1750:1850))counts=tempcounts/sumsfitfun=@(A,lambda) A(1).*exp(-(lambda-A(2)).^2/(2.*A(3).^2))dcounts=abs((counts)).^(1/2)w=abs(1./(counts+1))startvals=[0.2,780,2][peakfit,peakfitvalues,peakfitsigmas,rchi2]=advancedfit(fitfun,startvals,lambdas,counts,w)Degs(6)WaveL(6)=peakfitvalues(2)

09/04/07 11:13 PM C:\Documents and Settings\Carlos\My ...\caliblaserknobdegree2.m 3 of 3

WaveLsigma(6)=peakfitsigmas(2) %---------------------------- infile='data/3.Master.sample.txt'data=dlmread(infile)lambdas = data(:,1)tempcounts = data(:,2)sums=sum(tempcounts(1750:1850))counts=tempcounts/sumsfitfun=@(A,lambda) A(1).*exp(-(lambda-A(2)).^2/(2.*A(3).^2))dcounts=abs((counts)).^(1/2)w=abs(1./(counts+1))startvals=[0.2,780,2][peakfit,peakfitvalues,peakfitsigmas,rchi2]=advancedfit(fitfun,startvals,lambdas,counts,w)Degs(7)WaveL(7)=peakfitvalues(2)WaveLsigma(7)=peakfitsigmas(2) %--------------------------------------%Fit peak trends%--------------------------------------- fitfun=@(A,Degs) A(1).*Degs+A(2)

startvals=[0.01,770]damnaxis=axes('FontSize',12)xerror=2*ones(1,7)errorbarxy(Degs,WaveL,xerror,WaveLsigma,xerror,WaveLsigma,'.','blue')hold on[peakfit,peakfitvalues,peakfitsigmas,rchi2]=advancedfit(fitfun,startvals,Degs,WaveL,WaveL) Degs2 = linspace(-40,40,100)plot(damnaxis,Degs2,peakfit(Degs2),'r','LineWidth',2,'color','red')

xlabel(damnaxis,'Knob $\theta$ (degrees)','Interpreter','latex','FontSize',14)ylabel(damnaxis,'Center Wavelength (nm)','Interpreter','latex','FontSize',14) fitentry=advancedfitlegend(peakfitvalues,peakfitsigmas,rchi2,'$A \theta + \lambda_0$','A','$\lambda _0$')gcflegend('Observed Data',fitentry,'Interpreter','latex','FontSize',12, 'Location','NW') %-------------------------------------------------------------- print('-depsc2',knoboutfile)

10/04/07 12:51 AM C:\Documents and Settings\Carlos\My ...\caliblaserknobdegree3.m 1 of 3

%This can be used to generate plots of the laserclear allclose alloutfile='eplots/knobcalib1-10apr.eps'knoboutfile='eplots/knobcalib2-10apr.eps' %-----------------------infile='data/m15-0degrees.Master.sample.txt'data=dlmread(infile)lambdas = data(:,1)tempcounts = data(:,2)

sums=sum(tempcounts(1750:1795))counts=tempcounts(1750:1795)./sums lambdas=lambdas(1750:1795) fitfun=@(A,lambda) A(1).*exp(-(lambda-A(2)).^2/(2.*A(3).^2))dcounts=abs((counts)).^(1/2)w=abs(1./counts)startvals=[0.2,780,2]

plot(lambdas,counts,'xr','LineWidth',2) [peakfit,peakfitvalues,peakfitsigmas,rchi2]=advancedfit(fitfun,startvals,lambdas,counts,w)Degs(1)WaveL(1)=peakfitvalues(2)WaveLsigma(1)=peakfitsigmas(2)hold onftype = fittype('gauss1')

lambdas2=linspace(770,800,1000) plot(lambdas2,peakfit(lambdas2),'r','LineWidth',2,'color','red')

xlabel('Wavelength, (nm)','Interpreter','latex','FontSize',14)ylabel('Intensity (normalized)','Interpreter','latex','FontSize',14)

%fitentry=fitlegend(peakfit,errors,'$A e^-(\frac\lambda - \lambda _0\sigma)^2$',

fitentry1=advancedfitlegend(peakfitvalues,peakfitsigmas,rchi2,'$A e^-\frac(\lambda - \lambda _0)^2(2\sigma)^2$','A','$\lambda _0$','$\sigma$') %-----------------------------------------infile='data/m15-45degrees.Master.sample.txt'data=dlmread(infile)lambdas = data(:,1)tempcounts = data(:,2)

10/04/07 12:51 AM C:\Documents and Settings\Carlos\My ...\caliblaserknobdegree3.m 2 of 3

sums=sum(tempcounts(1750:1850))counts=tempcounts/sums fitfun=@(A,lambda) A(1).*exp(-(lambda-A(2)).^2/(2.*A(3).^2))dcounts=abs((counts)).^(1/2)w=abs(1./counts)startvals=[0.2,780,2]plot(lambdas,counts,'xb','LineWidth',2)[peakfit,peakfitvalues,peakfitsigmas,rchi2]=advancedfit(fitfun,startvals,lambdas,counts,w)Degs(3)WaveL(3)=peakfitvalues(2)WaveLsigma(3)=peakfitsigmas(2) ftype = fittype('gauss1')

lambdas2=linspace(770,800,1000)plot(lambdas2,peakfit(lambdas2),'b','LineWidth',2,'color','blue')fitentry3=advancedfitlegend(peakfitvalues,peakfitsigmas,rchi2,'$A e^-\frac(\lambda - \lambda _0)^2(2\sigma)^2$','A','$\lambda _0$','$\sigma$')%----------------------------------------- infile='data/m15-90degrees.Master.sample.txt'data=dlmread(infile)lambdas = data(:,1)tempcounts = data(:,2)sums=sum(tempcounts(1750:1850))counts=tempcounts/sums fitfun=@(A,lambda) A(1).*exp(-(lambda-A(2)).^2/(2.*A(3).^2)) dcounts=abs((counts)).^(1/2)w=abs(1./counts)startvals=[0.2,780,2]plot(lambdas,counts,'xk','LineWidth',2)[peakfit,peakfitvalues,peakfitsigmas,rchi2]=advancedfit(fitfun,startvals,lambdas,counts,w)Degs(5)WaveL(5)=peakfitvalues(2)WaveLsigma(5)=peakfitsigmas(2) ftype = fittype('gauss1')

lambdas2=linspace(770,800,1000)plot(lambdas2,peakfit(lambdas2),'k','LineWidth',2,'color','black')fitentry5=advancedfitlegend(peakfitvalues,peakfitsigmas,rchi2,'$A e^-\frac(\lambda - \lambda _0)^2(2\sigma)^2$','A','$\lambda _0$','$\sigma$')axis([775 800 0 0.25]) legend('0 Degrees',fitentry1,'45 Degrees',fitentry3,'90 Degrees',fitentry5,'Interpreter','latex','FontSize', 10, 'Location','NE') print('-depsc2',outfile)

:= 1000

:= 100

:= 11000000000

:= 2

:= 100000

:= 1000

:= 2.000000000 10-9

:= 1.000000000 10-9

:= 11253.95394

:= 0.1400211448

:= → 1

1 + + 1( ) + 2 2 2

:= ln( )

1. 1e+061e+05.1e5.1e41.

.1e3

.1

.1e-1

.1e2

E Data Sheets

E.1 Tunable Laser Components

The following pages contain copies of the datasheets relevant to the tunable laser.

59

185

HL7859MG

Visible High Power Laser Diode

Description

The HL7859MG is a 0.78 µm band GaAlAs laser diode with a multi-quantum well (MQW)structure.It is suitable as a light source for optical disc memories and various other types of optical equipment.Hermetic sealing of the small package (φ5.6 mm) assures high reliability.

Application

• Optical disc memories.

Features

• High output power : 35 mW (CW)

• Visible light output : λp = 775 to 795 nm

• Small package : φ 5.6 mm dia.

• Low astigmatism : 5 µm Typ (PO = 5 mW)

HL7859MG

186

Absolute Maximum Ratings (TC = 25°C)

Item Symbol Value Unit

Optical output power PO 35 mW

Pulse optical output power PO (pulse) 42 * mW

Laser diode reverse voltage VR(LD) 2 V

Photo diode reverse voltage VR(PD) 30 V

Operating temperature Topr –10 to +60 °C

Storage temperature Tstg –40 to +85 °C

Note: Pulse condition : Pulse width = 1 µs, duty = 50%

Optical and Electrical Characteristics (TC = 25°C)

Items Symbols Min Typ Max Units Test Conditions

Optical output power PO 35 — — mW Kink free *

Threshold current Ith — 35 60 mA —

Operating voltage VOP — 2.1 2.5 V PO = 35 mW

Slope efficiency ηs 0.35 0.65 0.80 mW/mA 21 (mW) / (I(28 mW) – I(7 mW))

Lasing wavelength λp 775 785 795 nm PO = 35 mW

Beam divergence parallel

to the junction

θ// 8 9.5 12 deg. PO = 35 mW

Beam divergenceparpendicular to the junction

θ⊥ 18 23 28 deg. PO = 35 mW

Monitor current Is 0.2 — 2 mA PO = 35 mW, VR(PD) = 5 V

Asitgmatism AS — 5 — µm PO = 5 mW, NA = 0.4

Note: Kink free is confirmed at the temperature of 25°C.

HL7859MG

187

Curve Characteristics

HL7859MG

188

HL7859MG

189

0.100

0.350

2.350

2.450

0.100

0.930

0.05"x0.05"ANGLED CORNER4 PLACES

0.120" DIA. THRU4 PLACES

1.0300.960

0.440

0.550

0.338

0.330

1/16"

0.100

ALL HEADER POSTS0.25" SQUARE

0.330

0.290

Doc 0009-D01 Rev C, 3/21/02

435 Route 206 • P.O. Box 366 SALES 973-579-7227 Newton, NJ 07860-0366 FAX 973-300-3600

Thorlabs Model LD1255 Laser Diode Constant Current Driver

Description: The LD1255 was developed for operating laser diodes in a constant current mode up to a maximum of 250mA. The LD1255 allows the laser anode to be grounded for added ESD protection of lasers that have their anode electrically connected to the case. The laser operating current can be set with an on-board 12-turn trim pot, an external analog voltage (0 to +5VDC) or a combination of both. A disable pin and diode protection circuitry have been provided to limit voltage transients produced by the power supply during start up, shut down or by static shock. New Feature: • Low Current Noise • Low Temperature Drift • Added ESD Protection • Enable / Disable Pin Figure 1 LD1255 Top View Specifications: Output Current: 0.2 to 250mA Operating Mode: Constant Current Internal Current Control: 12 turn potentiometer (on board) Ext. Current Control: 0 – 5 Volt analog input voltage (J1 pin 4) Output Current Drift: 2 µA/°C (Typ)

Current Noise: < 1 µARMS Operating Voltage: +/- 8 to 12 Volts Dimensions: 2.5” x 1” ESD Protection: 160 msec slow start circuit 3.3V zener diode (forward voltage protection for LD) Schottky diode (reverse voltage protection for LD) LD DISABLE pin Signal Bandwidth: 1.2 kHz Monitor Photo Diode Transimpedance Gain: 1000 µV/µA (note warnings in Photodiode monitor current section) Max LD forward voltage: 3.3 Volts Operating Temp.: 10 to 30 °C Storage Temp.: -20 to 50 °C Warm-up Time: 30 min.

1 10

1 5 J2

J1

CURRENT ADJ

Doc No. 0009-D01 Rev C 3/21/02

Page 2

LD1255 OPERATION:

The LD1255 was designed to be used as either a stand alone circuit or a hybrid circuit that can be soldered to another circuit board (using the standard 0.1" headers provided). Four clearance holes are provided at the corners of the board for mounting the LD1255 to stand-offs. These holes may be enlarged to accommodate up to #4 screws. The LD1255 operates the laser anode at ground potential for added protection against ESD (most laser manufactures mount the laser with the anode to the laser case for thermal benefits). This requires that the LD1255 use a negative power supply to "pull" current from the ground-referenced laser anode. Grounding the laser case helps prevent ESD damage. There are two single row connectors located on the top of the LD1255. The 10 pin connector is used for the power supply input, the laser interface, and monitor signals. Table 1 lists the signals on J1:

J1 Pin Number Function 1 +V (+5 to +12VDC, 10mA) 2 COMMON 3 -V (-6 to -12VDC, 0.3A) provides power to laser 4 EXTERNAL CURRENT CONTROL (0 to +5V, or -V to (-V + 5) ) 5 DISABLE 6 LASER DIODE ANODE (internally connected to pin 2 ground on LD1255) 7 LASER DIODE CATHODE 8 MONITOR PHOTO DIODE ANODE (from laser) see Note 1. 9 PHOTODIODE MONITOR OUTPUT ( -1V / mA )

10 LASER CURRENT MONITOR OUTPUT (10mV / mA)

Table 1 - J1 Laser & Power Supply Interface

Note 1: The LD1255 photodiode monitor circuit only supports lasers that have a photodiode with an isolated anode. It will not support common cathode lasers such as the CQL7825/D and CQL7840/D. The 5 pin connector, J2, is used for selecting the External Current Control Mode of operation as shown in Table 2:

J2 Pins to Jumper Operating Mode 1to 2 Mode 1. COMMON referenced External Current Control 2 to 3 Mode 2. Disable External Current Control

Table 2 - J2 External Current Control Mode Select

SETUP: Laser & Power Supply Connection: The LD1255 requires a clean (not switching) DC bipolar power supply for optimum operation. The positive supply is used only for biasing low power amplifiers and only needs to supply 10mA of current. The laser drive current is derived from the negative power supply output therefore, it should be capable of providing up to -300mA of current. 1. Attach the DC power supply to J1 according to Table 1. 2. Attach the laser diode to J1 according to Table 1. 3. Select the desired Current Control Mode using J2 (see section below). 4. Turn the Current Control Potentiometer a full 12 turns counter clockwise to ensure the laser current is at a

minimum. 5. Apply power to the LD1255 and slowly turn the Current Control Potentiometer clockwise until the desired

operating current is achieved. Connect a DVM from Pin 10 of J1 to Pin 4 of J2 to monitor the laser current.

Doc No. 0009-D01 Rev C 3/21/02

Page 3

Circuit Disable A disable pin has been provided to allow the user to turn the laser diode output on or off without turning the units power supply off. The advantage to this is the elimination of turn-on/ turn-off transients produced by the power supply. If the disable switch is shorted to ground, a transistor will provide a short circuit across the laser diode. Note: It is highly recommended that the laser diode be disabled prior to a power supply turn-on or turn-off to prevent any transients from damaging the laser diode. Selecting External Current Control Mode: The current can also be externally controlled by a voltage source applied to J1 pin 4 (function generator, DAC output, etc.). The External Current Control voltage must be referenced to the common output of the power supply. The total drive current is determined by the sum of the manual set point and the External Current Control Voltage. WARNING: One of the following Operating modes must be selected BEFORE turning the LD1255 on. Otherwise, the laser will be overdriven and damaged. Mode 1. COMMON-referenced External Current Control voltage (i.e. 0 to +5V). An internal level shifter

allows the negatively-biased laser to be controlled by a COMMON-referenced control voltage. To enable this mode jumper pin 1 to 2 on J2.

In Mode 1, the laser current is: ILD = 50 * VPIN4 (mA) Mode 2. If the External Current Control is not to be used, it should be disabled by jumpering pins 2 and 3

on J2. Laser Current Monitor: The laser drive current can be monitored from pin 10 of J1. This output is referenced to the negative supply (J1 Pin 3 or J2 Pin 4) and has the following transfer function: VPIN10 = -V + ILD * 10 Hint: Using a DVM, the laser current can be read without having to compensate for the -V offset by attaching the (-) lead to J2 Pin 4 and the (+) lead to J1 Pin 10. Photodiode Current Monitor:

Warning: The LD1255 has a photodiode monitor circuit that only supports lasers having the laser anode attached to the photodiode cathode (such as all of the Toshiba lasers and the Philips laser diodes with the exception of the CQL7825/D and the CQL7840/D).

The use of the monitor input with common cathode lasers will cause damage to the laser. However, the LD1255 can be used safely with common cathode lasers as long as the photodiode is not connected to the driver. An on-board transimpedance amplifier is provided for lasers with internal monitor photodiodes that are supported by the LD1255 (see warning note above). The amplifier converts the photodiode current to a voltage that can be measured on J1 Pin 9 for monitoring the relative laser output power. The output of Pin 9 has the following transfer function: Eq. 1 VPIN9 = -1000 * IPD (V)

Doc No. 0009-D01 Rev C 3/21/02

Page 4

If the exact monitor current is known for a given laser power, this output can be converted to laser power as follows: Eq. 2 P = VPIN9 * α (mW) Where α is the monitor photodiode conversion factor (mW / mA). IMPORTANT NOTE: The LD1255 operates diode lasers only in a constant current mode. Caution must be used to avoid over driving the laser when operating the laser over widely varying temperatures. Diode lasers become more efficient as their operating temperature decreases. It is possible to over drive the laser when operating the laser near the maximum drive current if the laser temperature is lowered. Please consult the laser manufacturers data sheets. If you have any questions, please call Thorlabs and an engineer will be happy to assist you.

Thorlabs, Inc. 435 Route 206 N Newton, NJ 07860 (973) 579-7227 Phone (973) 300-3600 Fax www.thorlabs.com

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Part Number: C230TM-B

Related f=4.5mm 0.55NA Mounted Geltech™ Aspheric Lens, AR Coating: 600-1050nm350230-BE09RMSS1TM09SPW301

Design Wavelength (nm): 780Numerical Aperture: 0.55Diffraction Limited Range (nm): 600-1550Clear Aperture (nm): 4.95Effective Focal Length (mm): 4.51Magnification: InfiniteLaser Window Thickness (mm): 0.25Laser Window Material/Index: BK7/1.51RMS WFE (Axial @ 632.8nm Averaged Over Full Aperture): ≤0.065Glass (Corning): CO550Unmounted Optic: 350230-B

Aspheric vs. Spherical Lenses In laser diode systems, difficulties with aberration correction are compounded by thebeams’ high divergence angle. Since individual spherical lenses can refract light at only small angles before sphericalaberration is introduced, three or four elements are often required to collimate laser diode light. A single aspheric lenscollimates without introducing aberrations.

Conversely, when coupling into fiber, it is often necessary to focus the laser light to a diffraction limited spot. Singlespherical elements are typically not capable of achieving such a small spot size. Spherical aberration is the dominantfactor rather than the diffraction limit. Because the aspheric lenses are corrected to eliminate the spherical aberration,only diffraction limits the size of the focal spot. At this point it is necessary to use Gaussian beam optics to describethe behavior of laser light.

Price: $86.00 Each, Euro: €86,00 Availability: In Stock Weight: 0.00 lbs, 0.00 kg

Quantity:

ORDER : C230TM-B

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Copyright © 1999 - 2005 Thorlabs, Inc.

1

12.70.50

12.70.50

11969-E01 GT13-12

120036.9Ü

3.00.12

NOTE:FOR INFORMATION ONLY.NOT FOR MANUFACTURING.

A

5 4 3 2 1

MATERIAL:

PART NO.

TOLERANCES

PROPRIETARY AND CONFIDENTIAL

DIMENSIONS ARE IN INCHESLINEAR TOLERANCES: TWO PLACE DECIMAL: 0.010 THREE PLACE DECIMAL: 0.005ANGULAR: 30' SURFACE FINISH: 32 MICROINCHESPARALLELISM: 0.002FLATNESS: 0.002STRAIGHTNESS: 0.002CONCENTRICITY: 0.002PERPENDICULARITY: 0.002THREAD: CLASS 2 FIT

DRAWNENG APPR.MFG APPR.

NAMETITLE:

SIZEA

REV.

SCALE: 4:1 SHEET 1 OF 1THE INFORMATION CONTAINED IN THISDRAWING IS THE SOLE PROPERTY OFTHORLABS, INC. ANY REPRODUCTION IN PART OR AS A WHOLE WITHOUTTHE WRITTEN PERMISSION OFTHORLABS, INC. IS PROHIBITED.

UNLESS OTHERWISE SPECIFIED:

DWG. NO.

REV. # DESCRIPTION: NAME/DATE:

APTOTO

06/29/2006DATE

06/29/200606/29/2006

THORLABS INC. PO BOX 366NEWTON NJ

VISIBLE TRANSMISSION GRATING

SCHOTT B370

SPECIFICATIONS:DIMENSIONAL TOLERANCES: Ñ0.5mmTHICKNESS TOLERANCES: Ñ0.5mmGROOVES (LINES/mm):GROOVE ANGLE:

2739-S01 Rev B 4/30/01 Page 1 of 2

0.225

0.450

0.225

0.520

ANODE(RED) CATHODE(WHITE)

CENTER OFACTIVE AREA

FDS1010 DETECTORELEMENT

0.025

CERAMIC SUBSTRATE

ANODE CATHODE

3.520

30 GAUGE WIRE(2PLACES)

435 Route 206 • P.O. Box 366 Ph. 973-579-7227 Newton, NJ 07860-0366 FAX 973-300-3600

FDS1010 Si Photodiode

--Large Active Area --Low Capacitance

Electrical Characteristics

Spectral Response: 400-1100nm

Active Area: 9.7 x 9.7mm Rise/Fall Time (RL=50Ω): 45ns (5V)

Bandwidth (RL=50Ω, -3dB,5V): 8 MHz (typ.) NEP@900nm: 5.5 x 10-14 W/√Hz Dark Current: 600nA max (5V)

Junction Capacitance (CJ) 375pF @ 5V (typ) Package: 0.45” x 0.52”

ceramic wafer Maximum Ratings

Damage Threshold CW: 100 mW/cm2

Max Bias Voltage: 20V Storage Temperature: -10 to 60 °C

Operating Temperature: -20 to 70 °C The Thorlabs FDS1010 photodiode is ideal for measuring both pulsed and CW light sources, by converting the optical power to an electrical current. The Si detector is mounted on a 0.45”x0.52” ceramic wafer package with an anode and cathode. The photodiode anode produces a current, which is a function of the incident light power and the wavelength. The responsivity ℜ (λ), can be read from Figure 1 to estimate the amount of photocurrent to expect. This can be converted to a voltage by placing a load resistor (RLOAD) from the photodiode anode to the circuit ground. The output voltage is derived as:

Vo = P * ℜ (λ) * RLOAD

The bandwidth, fBW, and the rise time response, tR, are determined from the diode capacitance, CJ, and the load resistance, RLOAD, as shown below. Placing a bias voltage from the photo diode cathode to the circuit ground can lower the photo diode capacitance.

fBW = 1/(2π * RLOAD *CJ), tR = 0.35/fBW

Related Thorlabs Products FDS010, FDS100, PDA55, PDA155, PDA255, PDA400, WS02, TM2448

2739-S01 Rev B 4/30/01 Page 2 of 2

Typical Circuit Diagram

Typical Plots

FDS1010 Responsivity

0.0

0.10.2

0.3

0.4

0.50.6

0.7

0.8

400 500 600 700 800 900 1000 1100

Wavelength (nm)

Res

posi

vity

(A/W

)

Figure 1: Typical Responsivity curve using Thorlabs calibration services.

1K

RLOAD0.1UF

FDS1010

+

-

Noise Filter (Typical Values)

1

PNZ300, PNZ300F (PN300, PN300F)Silicon PIN Photodiodes

For optical control systems

FeaturesFast response which is well suited to high speed modulated lightdetection

Wide spectral sensitivity

Low dark current and low noise

Good photo current linearity and wide dynamic sensitivity

Narrow directivity (PNZ300)

Wide directivity (PNZ300F)

PIN Photodiodes

Absolute Maximum Ratings (Ta = 25˚C)

Parameter Symbol Ratings Unit

Reverse voltage (DC) VR 50 V

Power dissipation PD 100 mW

Operating ambient temperature Topr –25 to +85 ˚C

Storage temperature Tstg –30 to +100 ˚C

PNZ300FGlass window

4.5

0.2

1: Anode2: Cathode

Unit : mm

Unit : mm 4.6 0.15

Glass lens

2.54 0.25

1.0 0.2

1.0

0.15

1.0 0.2

1.0

0.15

5.75 max.

2- 0.45 0.05

6.3

0.3

12.7

min

.

453

12

PNZ300

1: Anode2: Cathode

4.6 0.15

2.54 0.25

5.75 max.

2- 0.45 0.05

12.7

min

.

453

12

Note) The part numbers in the parenthesis show conventional part number.

2

PNZ300, PNZ300F PIN Photodiodes

Electro-Optical Characteristics (Ta = 25˚C)

Parameter Symbol Conditions min typ max Unit

Dark current ID VR = 10V 0.1 10 nA

Photo currentPNZ300

IL VR = 10V, L = 1000 lx*130 55 µA

PNZ300F 5 7 µA

Peak sensitivity wavelength λP VR = 10V 800 nm

Response time tr, tf*2 VR = 20V, RL = 50Ω 1 ns

Capacitance between pins Ct VR = 10V, f = 1MHz 7 pF

Acceptance half anglePNZ300

θ Measured from the optical axis to the half power point10 deg.

PNZ300F 40 deg.*1 Measurements were made using a tungsten lamp (color temperature T = 2856K) as a light source.*2 Switching time measurement circuit

50Ω

λP = 800nmtd : Delay time

tr : Rise time (Time required for the collector photo current

to increase from 10% to 90% of its final value)

tf : Fall time (Time required for the collector photo current

to decrease from 90% to 10% of its initial value)

Sig.IN

RL

VR = 10V

Sig.OUT

(Input pulse)

(Output pulse) 10%

90%

tdtr tf

PD — Ta

Pow

er d

issi

patio

n

P D (

mW

)

120

100

80

60

40

20

Ambient temperature Ta (˚C )

0 20 40 60 80 1000– 20

IL — L

Illuminance L (lx)

Pho

to c

urre

nt

I L (µ

A)

VR = 10VTa = 25˚CT = 2856K

10 3

10 2

10

1

10 –1

10 10 3 10 410 210 –2

1

10 2

10

1

10 –1

1 10 10 210 –2

10 –1

Ta = 25˚C

ID — VR

Reverse voltage VR (V)

Dar

k cu

rren

t I D

(nA

)

PNZ 030

0

PNZ 300

F

3

PIN Photodiodes PNZ300, PNZ300F

ID — Ta10 3

10 2

10

1

10 –1

10 –2

Ambient temperature Ta (˚C )

VR = 10V

Dar

k cu

rren

t I D

(nA

)

– 40 20 60 100– 20 0 40 8010 –3

fC — RL10 3

10 2

10

1

10 –1

10 –2

External load resistance RL (Ω)

VR = 10VTa = 25˚C

Cut

off

freq

uenc

y

f C (

MH

z)

10 10 4 10 6 10 710 2 10 3 10 510 –3

IL — VR50

40

30

20

10

Reverse voltage VR (V)

VR = 10V, Ta = 25˚C, T = 2856K

Pho

to c

urre

nt

I L (µ

A)

0 20 30 5010 400

IL — Ta100

80

60

40

20

Ambient temperature Ta (˚C )

Pho

to c

urre

nt

I L (µ

A)

– 20 0 20 60 8040 1000– 40

VR = 10V

Ct — VR10 3

10 2

10

1

Reverse voltage VR (V)

Cap

acita

nce

betw

een

pins

C

t (p

F)

1 10 10 210 –1

10 –1

Ta = 25˚C

Spectral sensitivity characteristics100

80

60

40

20

Wavelength λ (nm)

Rel

ativ

e se

nsiti

vity

S

(%

)

400 600 800 1000 12000200

VCE = 10VTa = 25˚C

Directivity characteristics100

80

60

40

20

080 40 0 40 80

Angle θ (deg.)

Rel

ativ

e se

nsiti

vity

S

(%

)

PNZ 0300

PNZ 0300

L = 1000 lx

L = 500 lx

L = 100 lx

PNZ 300F

PNZ 0300

PNZ 300F

PNZ 0300

PNZ 300F

PN

Z 3

00F

PN

Z 0

300

Please read the following notes before using the datasheets

A. These materials are intended as a reference to assist customers with the selection of Panasonicsemiconductor products best suited to their applications.Due to modification or other reasons, any information contained in this material, such as availableproduct types, technical data, and so on, is subject to change without notice.Customers are advised to contact our semiconductor sales office and obtain the latest informationbefore starting precise technical research and/or purchasing activities.

B. Panasonic is endeavoring to continually improve the quality and reliability of these materials butthere is always the possibility that further rectifications will be required in the future. Therefore,Panasonic will not assume any liability for any damages arising from any errors etc. that may ap-pear in this material.

C. These materials are solely intended for a customer's individual use.Therefore, without the prior written approval of Panasonic, any other use such as reproducing,selling, or distributing this material to a third party, via the Internet or in any other way, is prohibited.

Request for your special attention and precautions in using the technical informationand semiconductors described in this material

(1) An export permit needs to be obtained from the competent authorities of the Japanese Govern-ment if any of the products or technologies described in this material and controlled under the"Foreign Exchange and Foreign Trade Law" is to be exported or taken out of Japan.

(2) The technical information described in this material is limited to showing representative character-istics and applied circuit examples of the products. It does not constitute the warranting of industrialproperty, the granting of relative rights, or the granting of any license.

(3) The products described in this material are intended to be used for standard applications or gen-eral electronic equipment (such as office equipment, communications equipment, measuring in-struments and household appliances).Consult our sales staff in advance for information on the following applications:• Special applications (such as for airplanes, aerospace, automobiles, traffic control equipment,

combustion equipment, life support systems and safety devices) in which exceptional quality andreliability are required, or if the failure or malfunction of the products may directly jeopardize life orharm the human body.

• Any applications other than the standard applications intended.

(4) The products and product specifications described in this material are subject to change withoutnotice for reasons of modification and/or improvement. At the final stage of your design, purchas-ing, or use of the products, therefore, ask for the most up-to-date Product Standards in advance tomake sure that the latest specifications satisfy your requirements.

(5) When designing your equipment, comply with the guaranteed values, in particular those of maxi-mum rating, the range of operating power supply voltage and heat radiation characteristics. Other-wise, we will not be liable for any defect which may arise later in your equipment.Even when the products are used within the guaranteed values, redundant design is recommended,so that such equipment may not violate relevant laws or regulations because of the function of ourproducts.

(6) When using products for which dry packing is required, observe the conditions (including shelf lifeand after-unpacking standby time) agreed upon when specification sheets are individually exchanged.

(7) No part of this material may be reprinted or reproduced by any means without written permissionfrom our company.

2001 MAR

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Specification

Minimum Quantity

Global Part Number 7BB-27-4Previous Part Number 7BB-27-4

Resonant Frequency 4.6kHz ±0.5kHz

Resonant Impedance 200ohm max.Capacitance 20.0nF ±30%

Measurement Condition of Capacitance [1kHz]

Plate Size 27.0mm Element Size 19.7mm Electrode Size 18.2mm

Thickness 0.54mm Plate Thickness 0.30mm Plate Material Brass

Drive Type External Drive

180mm Paper Tape 180mm Embossed Tape

330mm Paper Tape 330mm Embossed Tape

Bulk Case Bulk(Bag)

Ammo Pack 320Reel

Magazine Box 1500

Details

Part Numbering

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Dimensions

Features_and_Applications

Notice_(storage_and_operating_condition)

Notice_(soldering_and_mounting)

Notice_(handling)

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Please do not touch the component with bare hand because electrode may be corroded.

The component may be damaged if mechanical stress over this specification is applied.

Please pay attention to protect operating circuit from surge voltage provided by something of force such as falling, shock and temperature changing.

If DC voltage is applied to the component, silver migration may occur. Please pay full attention not to subject the component to DC voltage for long periods.

The resistor should be used as shown in Fig. A. A suitable resistance value should be chosen, preferably 1kΩ to 2kΩ. Instead of this measure, a diode may also be applied as shown in Fig. B. IC

Fig.A

IC

Fig.B

R

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30MM SQUARE THERMOELECTRIC COOLER

Larger Picture Available

New thermoelectric devices, prepped with a temperature cutoff switch. Originally intended for 12Vdc use in picnic and automotive coolers/ heaters. 127 thermocouples per device. deltaTmax=79degC, Thot=50degC, Vmax=16.1V. 30MM x 30MM x 3.3MM. Qmax=38.7 Watts, Imax=3.9A. CAT# PJT-5 Your Price: $9.75 each Special Quantity Discounts!

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5 of 10 people found the following review helpful:

Peltoer fogureof merit 04/02/2007

Reviewer: Dr JKeffery Lewins from Ca,nbridge, England

I would be grateful if this academic enquiry could be passed on to your technical staff. Writing up my teaching notes on Peltier coolers I am unsure of the definition of the conventional figure of merit Z outside the linear range. In the linbear range we have Z~S qd T where T is the absolute tenperature abd S a Seebeck term that can either be the Seebeck ratio (the voltahe dfference across the junctions divided by the temperature difference) or the first Seebek coeficient, the slope of the voltag with temperature at the non-ambient junction dV/dT. In the linear rnae there is no difference but outside this range, is tere any standard practice? If the ratio is taken, this is easier to measure exoerimentallu but would require a knwoedge of th ambinet temperature for use. If the irst voefficient is employed,

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E.2 Microwave Components

82

VC

OS &

PLO

s -

SM

T

11

11 - 108

For price, delivery, and to place orders, please contact Hittite Microwave Corporation:20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373

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HMC507LP5 / 507LP5E

MMIC VCO w/ HALF FREQUENCY

OUTPUT 6.65 - 7.65 GHz

v00.0406

General Description

Features

Functional Diagram

The HMC507LP5 & HMC507LP5E are GaAs InGaP Heterojunction Bipolar Transistor (HBT) MMIC VCOs. The HMC507LP5 & HMC507LP5E integrate resonators, negative resistance devices, varactor diodes and feature a half frequency output. The VCO’s phase noise performance is excellent over temperature, shock, and process due to the oscillator’s monolithic structure. Power output is +13.5 dBm typical from a +5V supply. The voltage controlled oscillator is packaged in a leadless QFN 5x5 mm surface mount package, and requires no external matching components.

Dual Output: Fo = 6.65 - 7.65 GHz Fo/2 = 3.325 - 3.825 GHz

Pout: +13.5 dBm

Phase Noise: -115 dBc/Hz @100 kHz Typ.

No External Resonator Needed

QFN Leadless SMT Package, 25 mm2

Typical Applications

Low noise MMIC VCO w/Half Frequency, for:

• VSAT Radio

• Point to Point/Multi-Point Radio

• Test Equipment & Industrial Controls

• Military End-Use

Electrical Specifications, TA = +25° C, Vcc = +5V

Parameter Min. Typ. Max. Units

Frequency RangeFo

Fo/26.65 - 7.65

3.325 - 3.825GHzGHz

Power OutputRFOUT

RFOUT/2+11+4

+16+10

dBmdBm

SSB Phase Noise @ 100 kHz Offset, Vtune= +5V @ RFOUT -115 dBc/Hz

Tune Voltage Vtune 2 13 V

Supply Current (Icc) (Vcc = +5.0V) 200 230 270 mA

Tune Port Leakage Current (Vtune= 13V) 10 μA

Output Return Loss 2 dB

Harmonics/Subharmonics 1/22nd3rd

35424

dBcdBcdBc

Pulling (into a 2.0:1 VSWR) 8 MHz pp

Pushing @ Vtune= 5V 15 MHz/V

Frequency Drift Rate 0.9 MHz/°C

MIX

ER

S -

SM

T

8

8 - 382

For price, delivery, and to place orders, please contact Hittite Microwave Corporation:20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373

Order On-line at www.hittite.com

HMC525LC4

GaAs MMIC I/Q MIXER

4 - 8.5 GHz

v01.0806

General Description

FeaturesTypical Applications

Electrical Specifications, TA = +25° C, IF= 100 MHz, LO = +15 dBm*

Parameter Min. Typ. Max. Min. Typ. Max. Units

Frequency Range, RF/LO 4.0 - 8.5 5.5 - 7.5 GHz

Frequency Range, IF DC - 3.5 DC - 3.5 GHz

Conversion Loss (As IRM) 8 11 7.5 9.5 dB

Image Rejection 20 35 30 40 dB

1 dB Compression (Input) +14 +15 dBm

LO to RF Isolation 33 45 40 50 dB

LO to IF Isolation 14 20 17 20 dB

IP3 (Input) +23 +23 dBm

Amplitude Balance 0.3 0.2 dB

Phase Balance 8 4 Deg

* Unless otherwise noted, all measurements performed as downconverter.

Functional Diagram

The HMC525LC4 is ideal for:

• Point-to-Point and Point-to-Multi-Point Radio

• VSAT

Wide IF Bandwidth: DC - 3.5 GHz

Image Rejection: 40 dB

LO to RF Isolation: 50 dB

High Input IP3: +23 dBm

RoHS Compliant 4x4 mm SMT Package

The HMC525LC4 is a compact I /Q MMIC mixer in a leadless “Pb free” RoHS compliant SMT package, which can be used as either an Image Reject Mixer or a Single Sideband Upconverter. The mixer utilizes two standard Hittite double balanced mixer cells and a 90 degree hybrid fabricated in a GaAs MESFET process. A low frequency quadrature hybrid was used to produce a 100 MHz USB IF output. This productis a much smaller alternative to hybrid style Image Reject Mixers and Single Sideband Upconverter assemblies. The HMC525LC4 eliminates the need for wire bonding allowing use of surface mount manufacturing techniques.