Laser Communication system

Prepared by :- Saif Ansari

B.Tech 2nd year

Laser Communication System• Laser communication is a system in which we send data using laser as

a carrier wave.• Laser communication system works on the principle of “Amplitude

modulation” process.• In this the amplitude of the carrier wave(laser) is varied according to

the instantaneous amplitude of modulating signal.

Block diagram

signalSignal transmitter laser

ReceiverSignal

Transmitter • It includes• Signal processing circuit (ADC).• Laser diode.• Modulator.

Receiver • It is a “Antenna” of the system.• It includes• Signal processing circuit (DAC).• Detector (some kind of photodiode).

Example• MCU-Multipoint control unit.• UART – Universal asynchronous receiver/transmitter system.

Communication systems • Optical cable communication.• Free space optical communication.• Laser communication in space.• Wave guide

Laser in optical cable system.• Fiber-optic cable has potential data rates of terabits per second.• Fiber-optic cable is lighter, faster than copper cable.• No EMI(electromagnetic interference) and doesn’t causes sparks.• Laser can move vast quantities of data more securely than other

forms of communication.• Fiber optics developed new technology WDM(wave division

multiplexing) that increases data rates by leaps and bounds.

Image for optical cable system

Free space optical communication• It is a optical communication technology that uses laser light in free

space to wirelessly transmit data.• Free space point to point optical links can be implemented using

infrared laser light.• Current market demands• In 2008, MRV communications introduced a FSO based system with a data

rate of 10gb/s having distance of 350m.• In 2013, MOSTCOM started to serially produce a new FSO base system with a

data of up to 10gb/sec having distance 2.5km.

Image for free space optical communication

Laser communication in space (artificial earth satellite transmission)

• For distances of millions of kilometers, artificial earth satellite transmission is used.• Current market demands• In November 2001 he worlds first laser data connection was achieved by ESA

( European space agency) Artemis satellite with CNES earth observation satellite.• In November 2014, the first ever gigabyte laser based communication was

achieved by EDRS( European data relay system).• Communication distance of 15 million miles( 24 million km)/tested.• It also fades away the noise, distance, and other types of disruptions

interfering with the wave journey.

Image for laser communication in space

Wave guide• Wave guide is a structure that guide waves.• They enable a signal to propagate with minimal loss of energy by

restricting expansion to one dimension or two.