1. The Design Of WIRELSS LASER Communication System Guided by: Mr. Charles Koruth Varghese Presented by:Dennies Kurian Lecturer ECE S7 E.C A 36

2.  Point to point communication  Laser generated by laser diode can be used as carrier  It is applicable in civil and military field INTRODUCTION

3. THE SYSTEM  Consist Of Emitting And Receiving System  Emitting parts consists Of LASER, Modulator, Signal Source, Optical Emitting Antenna.  Receiving Parts –Electric Signal Processor, Optical Receiving Antenna

4. Block Diagram APT System Optical Emitting Antenna Spectro- scope Optical receiving antenna Modulator Filter Photoelectricity detector Dispose of information Export of incept information Signal sourceLASER

5. THE DESIGN OF EMITTING SYSTEM  High light power is generated by semiconductor laser  Wave length of LASER light source in air window  Reception is improved by the simple wavelength division multiplexer

6. THE DESIGN OF OPTICAL ANTENNA  Two types: Transmitive Antenna Reflective Antenna  Transmitive Antenna - Galileo Telescope System, Kepler Telescope System  Reflective Antenna -Newton System Gregory, Carse Green System

7. The Function Of Optical Emitting Antenna Compress the light beam to divergence angle Collimate the diverged light beams

8.  The Function Of Optical Receiving Antenna Receiving Antenna is The Core Of The Receiver Receive the Weak Laser Signals Generally PPM Mode is Used

9. DESIGN OF THE RECEIVING SYSTEM  Task: Resume light carrier wave’s carrying information with minimal added noise and distortion

10.  Components:  Light Detector-For High Sensitivity  Light Signal Processing  Photo Electric Detector-Change Weak Signal to Voltage Signal  Preamplifier-It must be Low Noise, Wide Frequency Band Amplifier.  Amplifier

11. MAIN FACTOR RESTRICTING WLC SYSTEM  Light waves wave band  In space light communication wave band, we should first consider solar radiation  In near sun direction we must choose the wave band with weakest solar radiation

12.  Communication distance  Suppose the emitting antenna radiation power P the maximum possible distance of the receiving antenna z,then the minimum power received by the antenna is

13.  Communication distance z increases nonlinearly with emitting power P  Improving the sensitivity communication distance z tend to increase

14.  How to make Communication channel smooth?  Decrease Air Influence.  Increase the Emitting Power.  Increase the Emitting Caliber.

15. APPLICATIONS  Data exchange between mobile base station.  Military communication.  Communication between satellites.

16. ADVANTAGES  Fast communication between two or more device.  High transferring speed.  High privacy.  Low cost.  Wide communication frequency band.

17. DISADVANTAGES  Transmittance of laser is very low in the disastrous weather such as rain or fog.  Air influence on laser signals attenuation is big.  Vibration or trembling of the platform which will make the communication part off the targeting position.

18. CONCLUSION  WLC is a communication system with vast applying foreground and big market potential can be used in data exchange between the mobile base stations, emergent communication systems, military communication, communication between satellites and so on.

19. REFERENCE Base Paper- Li Tianze, Wang Shuyun – “The Design and Analyses of Wireless Laser Communication System” 2009, IEEE. Free Space Satellite Laser Communicatio by -Adnan Cora-Hacer Atar http://en.wikipedia.org/wiki/Laser http://en.wikipedia.org/wiki/Pulse- position_modulation http://en.wikipedia.org/wiki/Transmittance

20. Thank you

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