Laser communication systems transmit information via laser beams through the atmosphere over long distances such as between planets and satellites. A laser transmitter contains a signal processing circuit and laser diode that creates the laser signal. The receiver uses a telescope and signal processor with detectors like PIN diodes or avalanche photodiodes to receive the signal. Common modulation techniques for laser communication are ON-OFF keying, pulse width modulation, and pulsed frequency modulation. Laser communication provides advantages over fiber optics and microwaves for long-distance communication in space and other applications due to its high bandwidth, security, and efficiency with a narrow beam. However, laser links can be affected by atmospheric conditions and need techniques like tuning and multiple transmitters to overcome issues like

1. Laser Communication
Submitted by:
Sayed Mohammed Tasmimul Huda
1609052
H.M.Ragib Shahrear Alam
1609053
07-Nov-18 1

2. INTRODUCTION
 Laser communications systems are wireless
connections through the atmosphere.
 Use Laser beams to transmit information between to locations
 Communication between long distance e.g. Planets,Satelite
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3. HOW DOES IT WORKS?
SIGNAL TRANSMITTER LASER
RECIVER SIGNAL
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4. Laser Transmitter
 The transmitter involves a signal processing
circuit and a laser.
 A laser diode is used to create laser signal.
 Laser diode includes Photodiodes for feedback to
ensure consistent output
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5. Receiver
Receiver involves :
Telescope (antenna)
Signal Processor
Detector
 PIN Diodes
 Avalanche Photodiodes
 Single or Multiple Detectors
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6. Modulation Techniques :
 ON-OFF
Keying(OOK)
 Pulse Width
Modulation(PWM)
 Pulsed Frequency
Modulation(PFM)
The LASER Diode is being turned ON/OFF quickly as needed
according to the OOK/PWM/PFM signal.
OOK
PWM
PFM
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7. WHY LASER COMMUNICATION
Current mostly used high speed
technologies:
 Fiber optics
 Microwave
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8. Why not Fiber Optics??
Installation cost
 Maintenance cost
 Cannot be used in Satellite
links
Laser Communication is low cost and can be
applicable where Fiber Optics is impractical to use.
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9. Why not Microwave??
 Beam width: Laser beam
width is narrower than that of
Microwave antennas.
 Bandwidth: very much larger for
Laser than microwave.
 Security: Laser is more secure
than microwave.
 Power: Low power needed
for laser compared to microwave.
 Very antenna size for Laser
as compared to microwave.
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10. ADVANTAGE
 Ease of deployment
 Can be used to power devices
 High bit rates
 Low bit error rates
 Full duplex operation
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11. DISADVANTAGE
Laser link can be affected by-
 Atmospheric absorption
 Fog, Rain, Pollution (smoke)
 Physical obstructions
 Solar radiations
 These can be reduced by using Laser tuning,multiple
number of transmitters, filters etc.
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12.  Defense and sensitive areas
 At airports for communication across
the runways
 Mass communication
 NASA
 Satellite – satellite communication
 Earth – satellite communication
CURRENT APPLICATIONS
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13. 07-Nov-18 13
Opportunities For Student Involvement
•LASER Research
•LASER Modulation Circuitry
•Encoding/Decoding Circuitry
• LASER Research
• LASER Modulation Circuitry
• Encoding/Decoding Circuitry

14. THANK YOU