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1. GOVERNMENT ENGINEERING COLLEGE RAMNAGARA-562159 Department of Electronics and Communication Presentation on “ LASER COMMUNICATION ” Under the Guidance of Presented By Dr. HEMANTH KUMAR C S BALAJI N Asst.Prof.Dept of ECE GECR 1GG21EC402 ECE, GECR (2023-2024) 1

2. Laser Communication : A Technical Seminar A Over View Of The Laser Communication Technology, Its Invention, Uniqueness, Current Application , & Literature Survey. ECE, GECR (2023-2024) 2

3. Introduction Literature Survey What Is Laser Communication ? Working System Processing Of Electrical Signal To Light Application Advantages Disadvantages Future scope Conclusion CONTENT ECE, GECR (2023-2024) 3

4. Introduction Laser communication is one of the key area in wireless Communications. Due to its low noise ratio makes its one of the well suited communication medium for exchange of information. Laser communications systems are wireless connection through the atmosphere. Which is focused on decreasing the noise ratio in optical communication system. Laser communications systems work similarly to fiber optic links, except the beam is transmitted through free space. ECE, GECR (2023-2024) 4

5. Literature Survey YEAR DEVELOPMENT RESEARCHERS / INSTITUTION RESEARCH PAPER PUBLICATION 2022 Development of integrated photonics for laser communication MIT, UC Berkeley, and others "Integrated Photonics for Free-Space Optical Communications" Nature Photonics 2019 Demonstration of free-space quantum communication Various research groups "Free-Space Quantum Communications" Optica 2013 Development of wavelength division multiplexing for laser communication University of California, San Diego "Wavelength Division Multiplexed Optical Wireless Transmission" Journal of Lightwave Technology 2008 Demonstration of multi-gigabit laser communication NASA, ESA, and others "High Data Rate Laser Communications for NASA's Space Communications Networks" IEEE Aerospace Conference ECE, GECR (2023-2024) 5

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. ECE, GECR (2023-2024) 6 L ight A mplification by S timulated E mission of R adiation

7. Working System ECE, GECR (2023-2024) 7

8. Working System Laser Communication System mainly comprise of 2 sections such as Transmitter section and Receiver section. Transmitter section is used to transmit the data and sound signals, which comprised by microphone, Conditioning ckt, analog to digital converter and laser diode to generate medium for transmission of signals. Transmitter converts the signal into laser beam and transmit it in a straight line. The receiver section is used to receive the laser beam, using photo transmitter, which incorporated with the data or sound signals from the transmitter comprised of conditioning, MCR and Digital to Analog converter to extract the data signals from the received laser beam and given as a input to the speaker. ECE, GECR (2023-2024) 8

9. Processing Of Electrical Signal To Light Microphone input is conditioned so that full 8 bit data range of ADC is utilized. The MCU passes the signal to the UART. On the receiver side, the signal is read by a photo transistor. The UART reads these signals and generates a byte. This byte is sent to DAC through a port and applied to the speaker. ECE, GECR (2023-2024) 9

10. LASER TRANSMITTER The Transmitter involves a signal processing circuit, and a laser. A laser diode is used to create the laser signal. Laser Diodes include Photodiodes for feedback to insure consistent output. ECE, GECR (2023-2024) 10

11. LASER RECEIVER The receiver involves: Telescope(‘antenna’) Signal processor Detector PIN diodes Avalanche Photo Diodes(APD) Single or multiple detectors ECE, GECR (2023-2024) 11

12. modulation PAM - Output energy varies with amplitude of the supplied current. PWM - Output energy varies with pulse width. PFM-Output energy varies with pulse frequency(needs highest BW >100KHz) ECE, GECR (2023-2024) 12

13. LASER DIODE Laser Diodes include Photodiodes for feedback to insure consistent output ECE, GECR (2023-2024) 13

14. System of characteristics 01. Link Parameter. Type of laser, wavelength, type of link Semiconductor laser diodes, solid state lasers, fiber amplifier lasers. Lasers operate in single or multiple longitudinal modes. Single longitudinal mode Laser emits radiation at a single frequency Multiple longitudinal mode. multiple frequencies are emitted ECE, GECR (2023-2024) 14

15. continue b). Semiconductor laser diodes Reliable operations as direct sources Operating in 800-900 nm range High efficiency of about 50% Small size Output power ECE, GECR (2023-2024) 15

16. continue c). Solid state lasers Higher power levels, high peak power mode Operating at 1064 nm Increase in complexity and reliability d). Types of link Acquiston Acquiston time, false alarm rate, probability of detection Tracking Amount of error induced in the signal circuitry Communications Bit error rates ECE, GECR (2023-2024) 16

17. continue 02. Transmitter Parameters Laser characteristics, losses incurred in the transmit optical path, transmit antennae gain, transmit pointing losses Laser characteristics peak and average optical power pulse rate pulse width ECE, GECR (2023-2024) 17

18. CONTINUE 03. Channel Parameters Consists of Range, associated loss background spectral radiance spectral irradiance ECE, GECR (2023-2024) 18

19. CONTINUE 04. Receiver Parameters The receiver parameters are the Receiver antenna gain proportional to the square of effective receiver diameter in meters and inversely proportional to the square of the wavelength. Receive optical path loss optical transmission loss for systems employing the direct detection techniques. Optical filter bandwidth the spectral width of the narrow band pass filter employed in optical inter satellite links Receiver field of view ECE, GECR (2023-2024) 19

20. APPLICATIONS 01. Defense Industry and Sensitive Areas Protection. 02. Airport Runways ECE, GECR (2023-2024) 20

21. CONTINUE 03. Mass Communication. 04. NASA and Space Discovery. ECE, GECR (2023-2024) 21

22. 05. Satellite-to-Satellite Communications. ECE, GECR (2023-2024) 22

23. ADVANTAGES Ease of deployment• can be used to power devices License-free long range operation (in contrast with radio communication) High bit rates Low bit error rates Immunity to electromagnetic interference Full duplex operation• protocol transparency Increased security when working with narrow beam(s). ECE, GECR (2023-2024) 23

24. disadvantages Atmospheric absorption Fog, Rain, Pollution (smoke) Physical obstructions Solar radiations These can be reduced by using Laser tuning, multiple number of transmitters, filters etc ECE, GECR (2023-2024) 24

25. FUTURE SCOPE It is more secure and provides high bandwidth requirements. The low power consumption is also a great advantage. It can be the mostly used technique worldwide in near future ECE, GECR (2023-2024) 25

26. CONCLUTION Laser communications offers a viable alternative to RF communications for inter satellite links and other applications where high-performance links are a necessity. High data rate, small antenna size, narrow beam divergence, and a narrow field of view are characteristics of laser communications that offer a number of potential advantages for system design. ECE, GECR (2023-2024) 26

27. references ECE, GECR (2023-2024) 27

28. THANK YOU  ECE, GECR (2023-2024) 28