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LASER COMMUNICATION

LASER COMMUNICATION. L ight A mplification by S timulated E mission of R adiation. LASER. LASER stands for L ight A mplification by S timulated E mission of R adiation. A highly coherent, monochromatic and perfectly parallel beam of light. Production of laser.

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LASER COMMUNICATION

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  1. LASER COMMUNICATION

  2. Light Amplificationby Stimulated Emission of Radiation

  3. LASER LASER stands for Light Amplification by Stimulated Emission of Radiation. A highly coherent, monochromatic and perfectly parallel beam of light.

  4. Production of laser First successful laser was constructed by T.H. Maiman in 1960 using Ruby Laser. A few other lasers are helium-neon laser, carbon dioxide laser, dye laser, junction laser, etc.

  5. RUBY LASER

  6. 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.

  7. Free Space Laser Communication • Transmitting information via a laser beam • Video • Data • Sound • Terrestrial / Space based systems 010001100110111011001111001010000010101110010001111001011011

  8. How Does it Work? Laser Transmitter Signal Signal Receiver laser

  9. High Level design Photo resistor MCU MCU Conditioning PORT A/D UART UART Conditioning Conditioning Laser Diode

  10. What is the Transmitter? • The transmitter involves: • Signal processing electronics (analog/digital) • Laser modulator • Laser (visible, near visible wavelengths)

  11. Laser Diode Laser Diodes include Photodiodes for feedback to ensure consistent output. Obtained by polishing the two sides of a junction diode.

  12. What is the Receiver? The receiver involves:- Antenna Signal Processor Detector PIN diodes Avalanche Photo Diodes (APD) Single or Multiple Detectors

  13. Why Laser Communication? • Current high speed communications technology: • Radio • Fiber Optics

  14. Laser Link GeometryCritical Design Parameters Receive area = 200 cm2 Receiver sensitivity Beam Divergence = 3 mrad Distance = 1km Transmit Power Diameter = 3 m Beam area = 70686 cm2

  15. Why not Fiber Optics? • Not always possible to lay fiber lines • Physically / Economically not practical • Emergencies • LC being incorporated into fiber optic networks when fiber is not practical.

  16. 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 / Weight • LC antenna is much smaller than RF. • Security • Due to low divergence of laser beam, LC is more secure than RF.

  17. Current Applications • 1. Defense and sensitive areas. • 2. In surgery. • 3. Mass communication • 400 TV channels • 40,000 phone conversations • 4. In industry. • 5. In nuclear power production. • 6. In weather forecasting. • 7. NASA • Satellite - satellite • Earth – satellite Earth

  18. Groundstation Description • Control System (data and tracking) • Telescope & LASER Mounts • LASER & Transmission Optics • Receiving Package (photodetector) Satellite Description • Utilize Science Team’s Telescope & Processing Capability for LASER Communication • Transmission & Receiving Package.

  19. Uplink/Downlink Data Processing Sequence Transfer Optics Channel (Atmos.) Bits Bit Encoder to Symbol LASER Error Correction Symbol Recovery Receiving Optics Amplifier Bits

  20. Demerits Of Laser Communication • Require direct line-of-sight. • Operational distance is also a variable if there are intervening materials such as rain, smoke, fog, glass etc. • Limited wavelength range.

  21. THANK YOU!

  22. ANY QUERIES?

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