Rohan Ece 42 Free Space Laser Communication

8/6/2019 Rohan Ece 42 Free Space Laser Communication

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FREE SPACE LASER

COMMUNICATIONPRESENTED BY :

ROHAN BHATNAGAR

ECE VIIITH SEM

07EAYEC042


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TALK FLOW

Basic overview

System overview

Introduction

Multi- path laser communicationAdvantages

Disadvantages

Security aspects

Safety aspects

Application

Conclusion2/18


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WHAT IS FREE-SPACE LASER

COMMUNICATION

Data is transmitted by modulated laser light

where the laser beam travels through the

atmosphere.

Its a wireless connection through the

atmosphere.

The laser light across the link is at a

wavelength of between 780-920nm.

Two parallel beams are used, one for

transmission and one for reception.(4/18)


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BASIC OVERVIEW OF FREE SPACE

LASER COMMUNICATION

Runs in infrared spectrum.

Optical signal is in the range of THz

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SYSTEM OVERVIEW OF FREE

SPACE LASER COMMUNICATION

The system consists of two transceivers, each

capable of simultaneously transmitting &

receiving either analogue or digital

information.

User selects between either analogue or

digital information via means of two switches.

In normal operation, the system is a full

duplex analogue/digital communicator.

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HARDWARE:

It is divided into two main categories:

The analogue transceiver-including VU

meter.

The digital transceiver.

The design incorporates three circuits

which perform analogue modulation,

digital modulation, and signal strength

display.

The completed system houses all these

modules as a single unit, sharing the

critical input & output components. 8


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FREE SPACE MULTI-PATH LASER

COMMUNICATION SYSTEMS:All laser beams hit the target point(optics &

photo-diode of the receiver)coherently.

This is achieved by phase control analogcircuit.

ADVANTAGES OF MULTI-PATH LASERCOMMUNICATION SYSTEMS:

Robustness in performance(not all beams areinterrupted simultaneously).

Better safety.

Easier design and built of stable lasersources and optics.

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THE DEGRADATION EFFECTS

CAN BE CATEGORIZED AS:Propagation effect:

Due to presence of heavy fog, snow or smoke

blocks the line-of-sight between the units.

Sun is interfering the laser beam.

Mechanical insufficiencies:

As the optical beam is narrow, the link

performance is sensitive to vibration, wind

sway, and thermal expansion of the

equipment.11


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ADVANTAGES:

Eliminates the need of buried cable installations. No need of Govt. licensing.

No spectrum fees have to be paid.

No radio interference.

Systems are quickly deployable.

High data rate & security.

More highly directional then RF communication.

Extremely high bandwidth.

Large information throughput that is many times

greater than RF communication. Small antenna size.

One third in mass.

Half in power requirement.

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APPLICATIONS:

Transmission of digital computer data

(LAN interconnect) video, voice,

multiplexed data etc.

Provides bitrates up to 1.25 Gbps at

shorter distances.

Suitable for temporary connectivity needs

such as at conventions, sporting events,corporate & university campuses, militaryoperations etc.

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CONCLUSION:

Laser-com technology on path to be operationallyfielded in space in next decade

Revolutionary increases in capability andreductions in size ,weight & power.

Telecom-like interoperability standards shouldhelp keep costs down.

Continued R & D to achieve ultimate potential

Laser-com to/from aircraftMultiple users per terminal(multi-access)

Advanced technology for high sensitivity and highdata rates.

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Rohan Ece 42 Free Space Laser Communication

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