Lecture Fiber Optics Links and Networks

Semester II 2009/10 Dr Mohammad Faiz Liew Abdullah

1

MKE 1083 Advanced Optical Communication

Dr Mohammad Faiz Liew Abdullah

Lecture : Fiber Optics Links and Network

Department of CommunicationFaculty of Electrical and Electronic Engineering

University Tun Hussein Onn Malaysia


2

PON


3

Passive Optical Network(PON) Topologies

BUS

RING

STAR

No O/E conversionPassive optical couplers

Folded Bus, Tree and Mesh Networks also exist


4

Linear bus topology

,

10 log ( 1) 2 ( 2) 2o C thru TAP iL N

P N L NL N L L NLP

= + + + +


5

Attenuators

Singlemode Variable Attenuator Repeatable, variable attenuation from 2 to 40dB


6

Attenuators - contd.

iBandpass 1310/1550nmiFC, SC, ST, and D4 stylesiWavelength independentiPolarization insensitiveiLow modal noise

In line attenuatorDual window


7

Optical CouplersiOptic couplers either split optical signals into multiple paths or

combine multiple signals on one path. iThe number of input (N)/ output (M) ports, (i.e.s N x M size)

characterizes a coupler. iFused couplers can be made in any configuration, but they

commonly use multiples of two (2 x 2, 4 x 4, 8 x 8, etc.).


8

Coupler

iUses Splitter: (50:50) Taps: (90:10) or (95:05) Combinersi An important issue:

two output differ /2 in phasei Applications:

Optical Switches, Mach Zehnder Interferometers, Optical amplifiers, passive star couplers, ...


9

Directional Coupler

A directional coupler forms the basis of many distribution network.

1 2

34

We assume that power P1 is incident on port 1 of the coupler.

This power will divide between ports 2 and 3 according to he desired splitting ratio.

Ideally, no power will reach port 4, the isolated port.


10

Directional Coupler - cont


1 2

34

Throughput loss

Tap loss1

210log10 P

PLTHP =

1

310log10 P

PLTAP =


11

Directional Coupler - cont


1 2

34

Directionality/ Cross talk

Excess loss

Coupling Ratio Splitting Ratio (in dB)

1

410log10 P

PLD =

32

110log10 PP

PLE +=

32

310log10 PP

PCR +=


12

Coupler working principle

Put the cores close enough together to get a coupling effectPut the cores close enough together to get a coupling effect

All now depends on the length of the coupling sectionAll now depends on the length of the coupling section


13

Common commercial devicesCommon commercial devices

Planar Waveguide CouplerPlanar Waveguide Coupler


14

( )( )CzPPCzPP

202

201

sin

cos

==

Ccoupling coefficient

222 fiber coupler2 fiber coupler

PP44

PP00 PP11

PP33 PP22Z


15

Coupler - Integrated Waveguide Directional Coupler

P2 = P0 sin2 kz P1 = P0 - P2 = P0 cos2 kz

k = coupling coefficient = (m + 1)/2

P0

P1

P2

P3

zP4


16

Throughput port

Tap port

Coupling procedureCoupling procedure


17

3dB coupler

3dB 3dB couplercoupler

Coupler - symbol


18

Star Couplers

iOptical couplers with more than four ports. iTypes of star couplers:

transmission star couplerthe light at any of the input port is split equally through all output ports.

reflection star coupler


19

Star coupler

PP11

PPNN

PPii

11

ii

NN

(P1+P2++PN)/N(P(P11+P+P22+++P+PNN)/N)/N

Star Coupler: N input are mixed and made Star Coupler: N input are mixed and made available on 8 outputsavailable on 8 outputs

Reflective Coupler: input can be on any fiber and Reflective Coupler: input can be on any fiber and output is split equally among all fibersoutput is split equally among all fibers


20

Reflection Star Couplers

The light arriving at port A and is reflected back to all

ports. A directional coupler

separates the transmitted and received signals.

Source: Australian Photonics CRC


21

Fibre Star CouplerCombines power from N inputs and divided them between M outputs

NN

CR 1010 10110 loglog =

=Coupling ratio

= Ni iout

ineP

PL

,

log1010Excess loss

1

N

1

N

P1

PN

Power at any one output ).......(, Nio PPPnP ++= 211


22

Star Coupler - 8 X 8

12345678

1, 2, ... 8

1, 2, ... 8

No of 3 dB coupler NNN dBc 23 2 log=

N/2

N2log

Star couplers are optical couplers with more than four ports


23

Star Coupler - 8 X 8 - contd.

i If a fraction of power traversing each 3 dB coupler = Fp, where 0< Fp < 1.

Then, power lost within the coupler = 1- Fp.

Excess loss )(log log Npe FL 21010=

NN

CR 1010 10110 loglog =

=Coupling ratio(splitting loss)

Total loss = splitting loss + excess loss

NFLT 10103223110 log)log.( =


24

Example:

Consider a commercially available 32x32 single mode coupler made from a cascade of 3dB fused fiber 2x2 couplers, where 5% of the power is lost in each element. Find the total loss experienced by a signal as it passes through the coupler.

Solution:

Total Loss ( )10 1 3.322log0.95 log3216.2dB

= =


25

port1port1port2(50%)port2(50%)port3(50%)port3(50%)

But light entering on port2 will exit on port1 But light entering on port2 will exit on port1 attenuated attenuated by 50%(3dB)by 50%(3dB)! Thus if we try to combine two input ! Thus if we try to combine two input signals by using a Ysignals by using a Y--junction, the signals are combined junction, the signals are combined but each signal but each signal will lose half of its powerwill lose half of its power!!

Y coupler (splitter)


26

Y- Couplers

1 X 8 coupler

Y-junctions are 1 x 2 couplers and are a key element in networking.

IiI1

I2


27

Wavelength Selective Coupling/Splitting

The period of the shift is different for the two The period of the shift is different for the two different wavelengths. Each coupler/splitter must be different wavelengths. Each coupler/splitter must be designed for the particular wavelengths to be used. designed for the particular wavelengths to be used.


28

Types of couplers


29

Coupler - Characteristics

Design class No. of CR Le Isolationport (dB) directivity

(-dB)

2 x 2 2 0.1-0.5 0.07-1.0 40 to 55Single mode

2 x 2 2 0.5 1-2 35 to 40Multimode

N x N 3-32 0.33-0.03 0.5-8.0Star


30

Example of commercial coupler


31

Example

A 2x2 biconical tapered fiber has an input optical power level of Po=200W. The output powers at the other three ports are P1=90W, P2=85W and P3=6.3nW. Calculate the splitting/coupling ratio, excess loss, insertion loss and crosstalk.


32

Solution:

2

1 2

85100% 100% 48.6%90 85

PP P

= = + + 0

1 2

20010log 10log 0.5890 85

P dBP P

= = + +

1

20010log 10log 3.4790

oP dBP

= =

2

20010log 10log 3.7285

oP dBP

= = 3

3

0

6.3 1010log 10log 45200

P dBP

= =

Splitting Ratio =

Excess loss =

Insertion loss(port 0 to port 1)=

Insertion loss(port 0 to port 2)=

Crosstalk =


33

Splitters

i The simplest couplers are fiber optic splitters. i They possess at least three ports but may have more than 32 for more

complex devices. i Popular splitting ratios include 50%-50%, 90%-10%, 95%-5% and 99%-1%;

however, almost any custom value can be achieved. i Excess loss: assures that the total output is never as high as the input. It

hinders the performance. All couplers and splitters share this parameter. i They are symmetrical. For instance, if the same coupler injected 50 W into

the 10% output leg, only 5 W would reach the common port.

OutputOutput

Input


34

9.4 Switches

a two-position switch a bypass switch

Fiber optic switches reroute the optic signals. Switches are useful in distribution networks, measuring equipment, and experiments.

switches


35

1

2

3

FIBERS

GRIN LENSES SLIDING

PRISM

Sliding-prism, two-position switch

Two-position switch


36

Bypass switch

1

2 3

4

BYPASS STATE

1

2 3

4

BRANCH STATE

In the bypass state, ports 1 and 4 are coupled; ports2 and 3 are isolated.In the branch state, ports 1 and 4 are isolated; ports2 and 3 are coupled


37

MEMS Switches

iMEMS----Micro-Electro-Mechanical System MEMS Mirrors

The MEMS optical switch requires the capability to produce arrays of tiny movable mirrors to deflect light beams in a desired manner.

These mirror can be constructed in two ways:

MIRROR

HINGE

SUBSTRATE SUBSTRATE

HINGE

MIRROR

As thin-film mirrors As bulk mirrors


38

MEMS Switches

MIRROR

HINGE

SUBSTRATE SUBSTRATE

HINGE

MIRROR

As thin-film mirrors As bulk mirrors

iThe mirror movement can be controlled in a number of ways: electrostatic, electromagnetic, piezoelectric, or thermal.


39

MEMS Switches

MEMS switches are constructed in 2D and 3D In 2D MEMS switches, the light travels in a plane defined as the plane

of the mirror array.

INPUT FIBERS

COLLIMATORS

MIRROR DOWNOUTPUT FIBERS

MIRROR UP


40

MEMS Switches

iThe 3D MEMS switch is a bit more complicated to construct than the 2D switch. The switch insertion loss and the switching time are two

important property. The application of the MEMS switches-----OXC (Optical

Cross Connect)


41

I/O Fibers

Imaging LensesReflector

MEMS 2-axis Tilt Mirrors

MEMS arraysMEMS arrays


42

1N MEMS Switch11N MEMS SwitchN MEMS Switch


43

Fiber Bragg Gratings (FBG)

FBG is a periodic refractive index variation (Period ) written along the fibre (single-mode) core using high power UV radiation.

All the wavelengths satisfying the condition 0 = 2 neff are reflected

If the optical period is 0 / 2, the grating reflects wavelength 0selectively. Useful in filtering communication channels in or out.


44

Laser BeamLaser Beam

--11 +1+100


45

lengthlength

Period Period

= effn2Selected Selected wavelengthwavelengthcore indexcore index

Grating Grating periodperiod

Fiber Bragg GratingsFiber gratings are a periodic variation in the refractive index of the core as measured along its axis.


46

))00 ++++== 22cos(cos( ++ zzAAnnNN nneffeffcorecoreFiber gratingFiber grating

0nN core =FiberFiber

Fiber Bragg Gratings


47

Applications of the Bragg grating

Filter for WDM systemWavelength-selective mirrors for fiber lasersWavelength stabilization of laser diodesStrain and temperature measurements in

composite fiber optic sensors.Dispersion compensationGain stabilization and equalization in erbium-

doped fiber amplifiersFixed filterTunable filters


48

Filter for WDM system


49

wavelength

For a given grating period a particular wavelength (frequency) of light is reflected. In this case yellow light will be reflectedIf the grating spacing is changed (e.g. reduced due to compression of the fibre or a drop in temperature} the wavelength of the reflected light changes. In this case it becomes higher and reflects blue light

In practice the colour shifts will be much finer than those illustated

Optical fibre

Grating pattern etched into body of fibre

Detector

http://www.co2sink.org/ppt/fbganimation.ppt

Fiber Bragg Gratings (FBG)


50

Optical Isolator

i laser diodes are particularly sensitive to light energy reflected back from the rest of the system. The reflected light increases the noise in the emitted beam, degrading system performance.iAn optical isolator will ensure a low level of return to the laser

diode. It is a one-way transmission line. It will allow propagation in only one direction along the fiber.iInsertion loss:

Low loss (0.2 to 2 dB) in forward direction

High loss in reverse direction:20 to 40 dB single stage, 40 to 80 dB dual stage)

iReturn loss: More than 60 dB without connectors


51

IsolatorsIsolators

Isolator/coupler hybridsIsolator/coupler hybrids

Example Isolator


52

Optical Circulators

iBased on optical crystal technology similar to isolators Insertion loss 0.3 to 1.5 dB, isolation 20 to 40 dB

iTypical configuration: 3 port device Port 1 -> Port 2 Port 2 -> Port 3 Port 3 -> Port 1

Agilent Tech. LW Div.


53

Optical Add Drop

2

3

1, 2, 3, 4,1, 3, 4,

2 2

1, 2, 3, 4,1

3 port circulator

FBGcoupler

Dropped w

avelength


54

Operation

iAn input signal at port 1 is sent on out at port 2. iAll wavelength except 2 pass through the FBG.

iSince 2 satisfies the FBG condition, it gets reflected, enters port 2 of the circulator, and exits at port 3 as a dropped wavelength.iNew information can be transmitted using 2 to the

network by coupler.


55

Multiplex & Demultiplex


56

DWDM


57

Baseband Transmission


58

Baseband Transmission


59

Example : Analog to Digital


60

Data Rate & Bandwidth


61

Transmission Impairments


62

Modulation : Digital Data, Analog Signal


63

Amplitude Modulation and ASK


64

Frequency Modulation and FSK


65

Phase Modulation and PSK


66

Amplitude Shift Keying


67

Frequency Shift Keying


68

Phase Shift Keying


69

Multiple Access Methods

iTDMA Time Division Multiple Access Done in the electrical domain

iSCMA Sub Carrier Multiple Access FDM done in the electrical domain

iCDMA Code Division Multiple Access Not very popular

iWDMA Wavelength Division Multiple Access (The most promising)


70

Sub Carrier Multiplexing


71

Single Mode Fiber

Baseband Data

Baseband-RFModulation

RF-Optical Modulation

Optical - RF Demodulation

Gain BPF

200 THz1.8 GHz

RF-Baseband Demodulation

Baseband Data

Receiving End

Transmitting End

A Closer Look.

Two different Modulations for each RF Carrier !


72


iEach modulating RF carrier will look like a sub-carrieriUnmodulated optical signal is the main carrier iFrequency division multiplexed (FDM) multi channel systems

also called as SCM

Frequency

Unmodulated (main) carrier

Sub-carriers

f1

f2

f1

f2

f0


73


iAbility to both analog and digitally modulated sub-carriersiEach RF carrier may carry voice, data, HD video or digital

audioiThey may be modulated on RF carriers using different

techniquesiMultiple digital signals are multiplexed onto one RF signal

and then sent at one optical wavelength. iMUX and DEMUX accomplished electronically not

optically. iLimited by BW of electrical and optical components. iCan be combined with other multiplexing schemes such as

SONET (Synchronous Optical Network) and DWDM to extend transmission capacity.


74

TDMA

iSignals are multiplexed in timeiThis could be done in electrical domain (TDMA)

or optical domain (OTDMA)iHighly time synchronized transmitter/receiveriStable and precise clocksiMost widely used (SONET, GPON etc.)


75

Time Division Multiplexing (TDM)

Individual channels are modulated at high data rates (Channels A-C, more would be used in an actual system). An Optical Pulse generator forms high-speed pulses at rates less than the period of the transmitted data. The bit period for these signals is compressed to T/N, multiplexed, and transmitted through optical fiber. A high-speed clock and regenerator demodulates the signals. All optical 3R regeneration processes (re-amplifying, re-shaping, and re-timing) can greatly extend the capability of this technique beyond 100 Gb/s). A demonstration of 1.28 Tb/s has been demonstrated (Nakazawa, et.al., Elect. Lett. 2000).


76

Code Division Multiplexing (CDM)

Each channel transmits its data bits as a coded channel specific sequence over available BW, wavelength, and time slots.


77

Space Division Multiplexing (SDM)

i The channel routing path is determined by different spatial positions (fiber locations). i High BW space switching matrix is formed.


78

OSI & Layer Model

This Course


79

Types of Networks

iLocal Area Network (LAN) Interconnect users in a localized area: a building,

campus or enterprise

iMetropolitan Area Network (MAN)iWide Area Network (WAN)

National, Regional

iSpecial Networks Undersea, Intercontinental


80

The Public Network

Long Haul Network


81

Global Network Hierarchy


82

Fiber in the Access End

Fiber increasingly reaches the user


83

Network Terminologies


84

Terms use in Fiber Optic Communication

Topology logical manner in which nodes linkedSwitching transfer of information from source to

destination via series of intermediate nodes; Circuit Switching Virtual circuit establishedPacket Switching Individual packets are directedSwitch is the intermediate node that stream the incoming

information to the appropriate outputRouting selection of such a suitable pathRouter translates the information from one network to

another when two different protocol networks are connected (say ATM to Ethernet)


85


86


87

Optical Cross Connects


88

Synchronous Optical Networks

iSONET is the TDM optical network standard for North America (It is called SDH in the rest of the world)iIt focus on the physical layer

iSTS-1, Synchronous Transport Signal consists of 810 bytes over 125 usi27 bytes carry overhead informationiRemaining 783 bytes: Synchronous

Payload Envelope


89

SONET/SDH Bit Rates

STM-649953.28 OC-192

STM-324976.64 OC-96

STM-162488.32 OC-48

STM-81244.16 OC-24

STM-4622.08 OC-12

STM-1155.52 OC-3

-51.84OC-1

SDHBit Rate (Mbps)SONET


90

Digital Transmission Hierarchy (T-Standards)

Additional framing bits stuffed at each level to achieve synchronization

Not possible to directly add/drop sub-channels

DS1

DS2

DS3

Predominant before optical era


91

Basic STS-1 SONET frame

STS-1=(90*8bits/row)(9rows/frame)*125 /frame 51.84 Mb/ss =


92

Basic STS-N SONET frame

STS-N signal has a bit rate equal to N times 51.84 Mb/sEx: STS-3 155.52 Mb/s


93

ATM over SONET


94


95

SONET Add Drop Multiplexers

ADM is a fully synchronous, byte oriented device, that can be used add/drop OC sub-channels within an OC-N signal

Ex: OC-3 and OC-12 signals can be individually added/dropped from an OC-48 carrier


96

SONET/SDH Rings

iSONET/SDH are usually configured in ring architecture to create loop diversity by self healingi2 or 4 fiber between nodesiUnidirectional/bidirectional traffic flowiProtection via line switching (entire OC-N

channel is moved) or path switching (sub channel is moved)


97

2-Fiber Unidirectional Path Switched Ring

Ex: Total capacity OC-12 may be divided to four OC-3 streams

Node 1-2OC-3

Node 2-4; OC-3


98

2-Fiber UPSR

iRx compares the signals received via the primary and protection paths and picks the best oneiConstant protection

and automatic switching


99

4-Fiber Bi-directional Line Switched Ring (BLSR)

Node 13; 1p, 2p 31; 7p, 8p Al

l

s

e

c

o

n

d

a

r

y

f

i

b

e

r

l

e

f

t

f

o

r

p

r

o

t

e

c

t

i

o

n


100

BLSR Fiber Fault Reconfiguration

In case of failure, the secondary fibers between only the affected nodes (3 & 4) are used, the other links remain unaffected


101

BLSR Node Fault Reconfiguration

If both primary and secondary are cut, still the connection is not lost, but both the primary and secondary fibers of the entire ring is occupied


102

Generic SONET networkLarge National Backbone

City-wide

Local Area

Versatile SONET equipmentare available that support wide range of configurations, bit rates and protection schemes


103

WDM Networks

iBroadcast and Select: employs passive optical stars or buses for local networks applications Single hop networks Multi hop networks

iWavelength Routing: employs advanced wavelength routing techniques Enable wavelength reuse Increases capacity


104

Single hop broadcast and select WDM

i Each Tx transmits at a different fixed wavelengthi Each receiver receives all the wavelengths, but selects (decodes) only

the desired wavelengthi Multicast or broadcast services are supported

i Dynamic coordination (tunable filters) is required

Star Bus


105

A Single-hop Multicast WDM Network


106

Multi-hop Architecture

Four node broadcast and select multihop networkEach node transmits at fixed set of wavelengths and receive

fixed set of wavelengthsMultiple hops required depending on destinationEx. Node1 to Node2: N1N3 (1), N3N2 (6)No tunable filters required but throughput is less


107

Data packet

In multihop networks, the source and destination information is embedded in the header

These packets may travel asynchronously (Ex. ATM)


108

Shuffle Net

Shuffle Net is one of several possible topologies in multihop networks

N = (# of nodes) X (per node)

Max. # of hops = 2(#of-columns) 1

(-) Large # of s(-) High splitting loss A two column shuffle net

Ex: Max. 2 X 2 - 1= 3 hops


109

Wavelength Routing

iThe limitation is overcome by: reuse, routing and conversioniAs long as the logical

paths between nodes do not overlap they can use the same


110

12X12 Optical Cross-Connect (OXC)Architecture

This uses space switching


111

Optical Cross Connects (OXC)

iWorks on the optical domainiCan route high capacity wavelengthsiSpace switches are controlled electronicallyiIncoming wavelengths are routed either to desired

output (ports 1-8) or dropped (9-12)iWhat happens when both incoming fibers have a

same wavelength? (contention)


112

4X4 Optical cross-connect

Wavelength switches are electronically configuredWavelength conversion to avoid contention


113

Optical Fiber Communication System Design

There are many factors that must be considered to ensure that enough light reaches the receiver. Without the right amount of light, the entire system will not operate properly.Basic system requirements as below:

transmission type:digital or analogperformance : BER for digital system

SNR for analog.transmission bandwidthspacing between the terminal equipment or intermediate repeatercostreliability


114

Fiber Optic System Design- Step-by-Step

Select the most appropriate optical transmitter and receiver combination based upon the signal to be transmitted (Analog, Digital, Audio, Video, RS-232, RS-422, RS-485, etc.).

Determine the operating power available (AC, DC, etc.).

Determine the special modifications (if any) necessary(Impedances, bandwidths, connectors, fiber size, etc.).

Carry out system link power budget.

Carry out system rise time budget (I.e. bandwidth budget).

If it is discovered that the fiber bandwidth is inadequate for transmitting the requiredsignal over the necessary distance, then either select a different transmitter/receiver (wavelength) combination, or consider the use of a lower loss premium fiber


115

Link Power Budget

Po = Receiver sensitivity (i.e. minimum power requirement)SM= System margin (to ensure that small variation the system operating

parameters do not result in an unacceptable decrease in system performance)


116

Power Budget

i Power budget is a detail description of how the available power is used.i Transmitter output T dBmi Receiver sensitivity R dBmi Excess power T-R dBi Splicing attenuation A1 dBi Fiber loss A2 dBi Penalty for transmitter realization A3 dBi Penalty for receiver realization A4 dBi Temperate effect A5 dBi Jitter A6 dBi Safety margin A7 dBi Total loss TA dBi Excess power margin T-R-TA


117

Link Power Budget - ExamplePower margin is normally provided in the analysis to allow for component aging, temperature fluctuations, and losses arising from components that might be added at future dates.


118

Example:The following parameters are established for a long haul single mode optical system operating at a wavelength of 1.3um.

Mean power launched from the laser transmitter -3 dBmCabled fiber loss 0.4dB /kmSplice loss 0.1dB/kmConnector losses at the transmitter and receiver 1dB eachMean power required at the APD receiver:

When operating at 35Mbit/s (BER 10-9) -55dBmWhen operating at 44Mbit/s (BER 10-9) -44dBm

Required safety margin 7 dBEstimate:i The maximum possible link without repeaters when operating at 35Mbit/s. It may be

assumed that there is no-dispersion-equalization penalty at this rate.i The maximum possible link without repeaters when operating at 44Mbit/s and

assuming no-dispersion-equalization penalty ati The reduction in the maximum possible link without repeaters of (b) when there is a

dispersion equalization penalty of 1.5 dB. It may be assumed for the purposes of this estimate that the reduced link length has the 1.5dB penalty.


119

Solution:

( )i o fc j cr aP P L M = + + +( ) ( )3 55 0.4 0.1 2 7odBm dBm L = + + +

0.5 52 9L = 43 860.5

L km= =

( ) ( )3 44 0.4 0.1 2 7odBm dBm L = + + +0.5 41 9L =

32 640.5

L km= =

( ) ( )3 44 0.4 0.1 2 7 1.5odBm dBm L = + + + +0.5 41 10.5L =

30.5 610.5

L km= =

(a)

(b)

(c)


120

Rise Time Budget

iTotal system rise timeiTsystem = 1.1(Ts2 + Tn2 + Tc2 + TD2 )1/2iTs : Source 10-90% rise timeiTD : Detector 10-90% rise timeiTn : intermodal dispersioniTc : intramodal/chromatic dispersioniRZ: BT (max) = NRZ: BT (max) =

iFor analog system, maximum 3 dB bandwidth is:iBW (max) =

systemT35.0

systemT7.0

systemT35.0


121

Example:

An optical fiber system is to be designed to operate over an 8km length without repeaters. The rise times of the chosen components are:

Source (LED) 8 nsFiber: intermodal 5 ns/kmIntramodal 1 ns/kmDetector(p-i-n) 6 ns

From system rise time considerations, estimate the maximum bit rate that may be achieved on the link when using an NRZ format.

Solution:Tsystem = 1.1(TS2 + Tn2 + TC2 + TD2 )1/2

= 1.1(82 + (8 x 5)2 + (8 x 1)2 + 62 )1/2= 46.2 ns

NRZ BT(max) = 9syst

0.7 0.7 15.2Mbit/sT 46.2 10

= =

Documents

Lecture Fiber Optics Links and Networks