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Laser Communication

This document discusses laser communication systems which transmit information via laser beams through free space, similarly to fiber optic links. It describes the components of the transmitter and receiver including signal processing electronics, lasers, modulators, telescopes and detectors. Applications mentioned include defense, satellites, airports and high speed mass communication.

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Ganpat Singh Sodha
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100 views17 pages

Laser Communication

This document discusses laser communication systems which transmit information via laser beams through free space, similarly to fiber optic links. It describes the components of the transmitter and receiver including signal processing electronics, lasers, modulators, telescopes and detectors. Applications mentioned include defense, satellites, airports and high speed mass communication.

Uploaded by

Ganpat Singh Sodha
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PPTX, PDF, TXT or read online on Scribd
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Laser Communication

Submitted By:BHANWAR SINGH 8 Sem. CS

What Is Laser Communication?


Laser communications systems are wireless connections through the atmosphere. They work similarly to fiber optic links, except the fact that, in lasers, beam is transmitted through free space.

Light
Amplification by Stimulated Emission of Radiation

Free Space Laser Communication


Transmitting

information via a laser beam

Video Data Sound


Terrestrial

/ Space based systems


010001100110 111011001111 001010000010 101110010001 111001011011

How Does it Work?

Signal

Transmitter

Laser Signal
laser

Receiver

What is the Transmitter?


The

transmitter involves:

Signal processing electronics (analog/digital) Laser modulator Laser (visible, near visible wavelengths)

RUBY LASER

Laser Diode
Laser Diodes include Photodiodes for feedback to insure consistent output.

Modulation
AM

Easy with gas lasers, hard with diodes


PWM

(Pulse Width Modulation) PFM (Pulsed FM)


Potentially the highest bandwidth (>100kHz)

What is the Receiver?


The

receiver involves:

Telescope (referred to as antenna) Signal processor Detector

-PIN diodes

-Avalanche Photo Diodes (APD) -Single or multiple detectors

Often both ends will be equipped with a receiver and transmitter

Why Laser Communication?


Current

high speed communications technology:

Radio Fiber Optics

Why not Fiber Optics?


Not

always possible to lay fiber lines

Satellites Combat zones Physically / Economically not practical Emergencies

LC

being incorporated into fiber optic networks when fiber is not practical.

Why not RF?


Bandwidth

for Laser Communication (LC) is 100 times greater than for RF.

Power

in LC is directed at target, so much less transmission power required. Also the power loss is less.

Size

LC antenna is much smaller than RF.

/ Weight

Security

Due to low divergence of laser beam, LC is more secure than RF.

Current Applications
Defense

and sensitive areas. At airports for communication across the runways. Mass communication
400

TV channels 40,000 phone conversations

NASA

Satellite - satellite Earth - satellite

Earth

Groundstation Description
Control

System (data and tracking) Telescope & LASER Mounts LASER & Transmission Optics Receiving Package (photodetector)

Satellite Description
Utilize Science Teams Telescope & Processing Capability for LASER Communication Transmission & Receiving Package.

Uplink/Downlink Data Processing Sequence


Bits
Bit Encoder to Symbol

LASER

Transfer Optics

Channel (Atmos.)

Error Correction Bits

Symbol Recovery

Amplifier

Receiving Optics

THANK YOU.

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