SlideShare uma empresa Scribd logo
1 de 20
Baixar para ler offline
Laser Communications
Contents
• Introduction
• Block Diagram
• Laser Transmitter And Receiver
• Laser Transmitter
• Receiver
• Modulation
• Gain Systems
• Filters
• Mounting System
• Pointing
• Why not Fiber Optics??
• Why not R.F??
• Advantages
• Disadvantages
• Applications
• Conclusion
• Reference
Introduction
• Laser communications systems are wireless connections through
the atmosphere.
• They work similarly to fiber optic links, except the beam is
transmitted through free space.
• While the transmitter and receiver must require line-of-sight
conditions, they have the benefit of eliminating the need for
broadcast rights and buried cables.
BLOCK DIAGRAM
LaserTransmitter and Receiver
LaserTransmitter Receiver
Optical fiber link
Direct Link
LaserTransmitter
• 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.
Receiver
The receiver involves:
• Telescope(‘antenna’)
• Signal processor
• Detector
 PIN diodes
 Avalanche Photo Diodes(APD)
 Single or Multiple detectors
Modulation :
• AM :
Easy with gas lasers, hard with diodes
• PWM (Pulse Width Modulation) :
Used by Ramsey in their kit
• PFM (Pulsed FM) :
Potentially the highest bandwidth (>100kHz)
Gain Systems :
Transmitter:
• Maximum output power
• Minimum divergence
Receiver:
• Maximum lens area
• Clarity
• Tight focus on detector
Filters :
• Sun shade over detector
• Shade in front of lens
• Detector spectral response
• Colored filters
 Absorb ~50% of available light
 Difficult to find exact frequency
Mounting System :
• Mounts and stands need only be as accurate as beam
divergence.
• Good laser diodes will be 1-2mR (milli-radian)
• A 32 pitch screw at the end of a 2' mount will yield 1mR per
revolution.
• Higher thread pitches allow shorter mounts which may be more
stable (against wind, vibration, wires)
• 1mR is 1.5' of divergence every 1000', 3' at 2000 ', etc.
Pointing
• GPS and Compass
• Scopes and Binoculars
• Strobe lights, large handheld floods, headlights
• HTs to yell when laser light is seen at remote location
Why not Fiber Optics??
• Not always possible to lay fiber lines :
 Satellites
 Combat zones
 Physically/Economically not practical
 Emergencies
 Laser Communication being incorporated into fiber optic
networks when fiber is not practical.
Why not R.F??
• Bandwidth :
 For laser communication is 100times larger than R.F.
• Power :
 In LC is directed at target, so much less transmission power
 Also the power loss is less.
• Size/Weight :
 LC antenna is much smaller than R.F.
• Security :
 Due to low divergence of laser beam ,LC is more secure than R.F.
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.
Disadvantages :
For terrestrial applications, the principal limiting factors are:
• Beam dispersion
• Atmospheric absorption
• Rain
• Fog (10..~100 dB/km attenuation)
• Snow
• Scintillation
• Interference from background light sources (including the Sun)
• Shadowing
• Pointing stability in wind
• Pollution / smog
Applications :
• Laser light is used in optical fiber communications to send information
over large distances with low loss.
• Laser light is used in underwater communication networks.
• Lasers are used in space communication, radars and satellites.
Conclusion
Laser communications offers a viable alternative to RF
communications for inter satellite links and other applications
where high-performance links are a necessity.
References
• www.studymafia.org
• www.google.com
• www.wikipedia.com
Laser Communications

Mais conteúdo relacionado

Mais procurados

smart antennas ppt
smart antennas pptsmart antennas ppt
smart antennas pptsanthu652
 
Laser communication ppt svist
Laser communication ppt svistLaser communication ppt svist
Laser communication ppt svistArghaya Goswami
 
Cisco WLAN - Chapter. 03 : wireless radio technology
Cisco WLAN - Chapter. 03 : wireless radio technologyCisco WLAN - Chapter. 03 : wireless radio technology
Cisco WLAN - Chapter. 03 : wireless radio technologyYaser Rahmati
 
Radar case study on aesa radar
Radar case study on aesa radarRadar case study on aesa radar
Radar case study on aesa radarVishal Bait
 
Infrared in mobile communications and networks
Infrared in mobile communications and networksInfrared in mobile communications and networks
Infrared in mobile communications and networksFarwaYaqoob
 
Array antenna and LMS algorithm
Array antenna and LMS algorithmArray antenna and LMS algorithm
Array antenna and LMS algorithmSHIVI JAIN
 
Fundamental Radar Concepts, Radar Systems Training
Fundamental Radar Concepts, Radar Systems TrainingFundamental Radar Concepts, Radar Systems Training
Fundamental Radar Concepts, Radar Systems TrainingTonex
 
radar and radar management
radar and radar managementradar and radar management
radar and radar managementkhalidmorsalin
 

Mais procurados (20)

LASER Communication
LASER CommunicationLASER Communication
LASER Communication
 
smart antennas ppt
smart antennas pptsmart antennas ppt
smart antennas ppt
 
Laser communication ppt svist
Laser communication ppt svistLaser communication ppt svist
Laser communication ppt svist
 
Cisco WLAN - Chapter. 03 : wireless radio technology
Cisco WLAN - Chapter. 03 : wireless radio technologyCisco WLAN - Chapter. 03 : wireless radio technology
Cisco WLAN - Chapter. 03 : wireless radio technology
 
Laser Communications
Laser CommunicationsLaser Communications
Laser Communications
 
Smart antenna
Smart antennaSmart antenna
Smart antenna
 
Multi-mission Phased Array Radar
Multi-mission Phased Array RadarMulti-mission Phased Array Radar
Multi-mission Phased Array Radar
 
Smart antenna
Smart antennaSmart antenna
Smart antenna
 
Unbounded Media
Unbounded MediaUnbounded Media
Unbounded Media
 
Radar case study on aesa radar
Radar case study on aesa radarRadar case study on aesa radar
Radar case study on aesa radar
 
Smart antennas
Smart antennasSmart antennas
Smart antennas
 
Infrared in mobile communications and networks
Infrared in mobile communications and networksInfrared in mobile communications and networks
Infrared in mobile communications and networks
 
Smart antenna
Smart antennaSmart antenna
Smart antenna
 
Smart Antenna
Smart AntennaSmart Antenna
Smart Antenna
 
MSc Defence PPT
MSc Defence PPTMSc Defence PPT
MSc Defence PPT
 
Smart antenna1
Smart antenna1Smart antenna1
Smart antenna1
 
Array antenna and LMS algorithm
Array antenna and LMS algorithmArray antenna and LMS algorithm
Array antenna and LMS algorithm
 
Fundamental Radar Concepts, Radar Systems Training
Fundamental Radar Concepts, Radar Systems TrainingFundamental Radar Concepts, Radar Systems Training
Fundamental Radar Concepts, Radar Systems Training
 
radar and radar management
radar and radar managementradar and radar management
radar and radar management
 
UNDERWATER SENSORS NETWORKS
UNDERWATER SENSORS NETWORKSUNDERWATER SENSORS NETWORKS
UNDERWATER SENSORS NETWORKS
 

Semelhante a Laser Communications

Semelhante a Laser Communications (20)

Laser communications ppt
Laser communications pptLaser communications ppt
Laser communications ppt
 
Laser.pptx
Laser.pptxLaser.pptx
Laser.pptx
 
Laser communiction
Laser communictionLaser communiction
Laser communiction
 
Laser Communications
Laser CommunicationsLaser Communications
Laser Communications
 
Free space optical communication system
Free space optical communication systemFree space optical communication system
Free space optical communication system
 
Laser communications ppt.pdf
Laser communications ppt.pdfLaser communications ppt.pdf
Laser communications ppt.pdf
 
laser communication pptx.pptx
laser communication pptx.pptxlaser communication pptx.pptx
laser communication pptx.pptx
 
LASER Communication
LASER CommunicationLASER Communication
LASER Communication
 
Data transmission
Data transmissionData transmission
Data transmission
 
Communication systems v7
Communication systems v7Communication systems v7
Communication systems v7
 
Lasers and optical fibre communications
Lasers and optical fibre  communicationsLasers and optical fibre  communications
Lasers and optical fibre communications
 
Lasser communication
Lasser communicationLasser communication
Lasser communication
 
Transmission media
Transmission mediaTransmission media
Transmission media
 
Free space optical communication
Free space optical communicationFree space optical communication
Free space optical communication
 
Microwave basics
Microwave basicsMicrowave basics
Microwave basics
 
Network in brief
Network in briefNetwork in brief
Network in brief
 
seminar ppt.pptx
seminar ppt.pptxseminar ppt.pptx
seminar ppt.pptx
 
Data comm 2 latest
Data comm 2 latestData comm 2 latest
Data comm 2 latest
 
5 transmission media
5 transmission media5 transmission media
5 transmission media
 
lesson_3.pptx
lesson_3.pptxlesson_3.pptx
lesson_3.pptx
 

Mais de UpendraSingamsetty

Smart Washing Machine Using NI LAB VIEW
Smart Washing Machine Using NI LAB VIEW Smart Washing Machine Using NI LAB VIEW
Smart Washing Machine Using NI LAB VIEW UpendraSingamsetty
 
BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 2)
BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 2)BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 2)
BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 2)UpendraSingamsetty
 
Basic Information of Ohm's law
Basic Information of Ohm's lawBasic Information of Ohm's law
Basic Information of Ohm's lawUpendraSingamsetty
 
BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 1)
BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 1)BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 1)
BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 1)UpendraSingamsetty
 
Basics concepts of A I,ANN,Genetic Algorithm,Fuzzy Logic
Basics concepts of A I,ANN,Genetic Algorithm,Fuzzy LogicBasics concepts of A I,ANN,Genetic Algorithm,Fuzzy Logic
Basics concepts of A I,ANN,Genetic Algorithm,Fuzzy LogicUpendraSingamsetty
 
A GIANT LEAP OF INDIA : SUNDAR BHARATH AND FEW SYMPTOMS AND PRECAUTIONS FROM ...
A GIANT LEAP OF INDIA : SUNDAR BHARATH AND FEW SYMPTOMS AND PRECAUTIONS FROM ...A GIANT LEAP OF INDIA : SUNDAR BHARATH AND FEW SYMPTOMS AND PRECAUTIONS FROM ...
A GIANT LEAP OF INDIA : SUNDAR BHARATH AND FEW SYMPTOMS AND PRECAUTIONS FROM ...UpendraSingamsetty
 
Emerging Civil Society Initiatives In Agriculture
Emerging Civil Society Initiatives In AgricultureEmerging Civil Society Initiatives In Agriculture
Emerging Civil Society Initiatives In AgricultureUpendraSingamsetty
 

Mais de UpendraSingamsetty (12)

SMART BLIND STICK
SMART BLIND STICK SMART BLIND STICK
SMART BLIND STICK
 
Smart Washing Machine Using NI LAB VIEW
Smart Washing Machine Using NI LAB VIEW Smart Washing Machine Using NI LAB VIEW
Smart Washing Machine Using NI LAB VIEW
 
BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 2)
BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 2)BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 2)
BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 2)
 
Basic Information of Ohm's law
Basic Information of Ohm's lawBasic Information of Ohm's law
Basic Information of Ohm's law
 
BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 1)
BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 1)BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 1)
BASIC CONCEPTS OF DATA NETWORKS AND PROTOCOLS (PART - 1)
 
Basics concepts of A I,ANN,Genetic Algorithm,Fuzzy Logic
Basics concepts of A I,ANN,Genetic Algorithm,Fuzzy LogicBasics concepts of A I,ANN,Genetic Algorithm,Fuzzy Logic
Basics concepts of A I,ANN,Genetic Algorithm,Fuzzy Logic
 
HACKING
HACKINGHACKING
HACKING
 
A GIANT LEAP OF INDIA : SUNDAR BHARATH AND FEW SYMPTOMS AND PRECAUTIONS FROM ...
A GIANT LEAP OF INDIA : SUNDAR BHARATH AND FEW SYMPTOMS AND PRECAUTIONS FROM ...A GIANT LEAP OF INDIA : SUNDAR BHARATH AND FEW SYMPTOMS AND PRECAUTIONS FROM ...
A GIANT LEAP OF INDIA : SUNDAR BHARATH AND FEW SYMPTOMS AND PRECAUTIONS FROM ...
 
Emerging Civil Society Initiatives In Agriculture
Emerging Civil Society Initiatives In AgricultureEmerging Civil Society Initiatives In Agriculture
Emerging Civil Society Initiatives In Agriculture
 
Capacitor and its types
Capacitor and its typesCapacitor and its types
Capacitor and its types
 
LCD AND LED SCREEN
LCD AND LED SCREENLCD AND LED SCREEN
LCD AND LED SCREEN
 
Waste Management
Waste ManagementWaste Management
Waste Management
 

Último

Easter in the USA presentation by Chloe.
Easter in the USA presentation by Chloe.Easter in the USA presentation by Chloe.
Easter in the USA presentation by Chloe.EnglishCEIPdeSigeiro
 
How to Add Existing Field in One2Many Tree View in Odoo 17
How to Add Existing Field in One2Many Tree View in Odoo 17How to Add Existing Field in One2Many Tree View in Odoo 17
How to Add Existing Field in One2Many Tree View in Odoo 17Celine George
 
CapTechU Doctoral Presentation -March 2024 slides.pptx
CapTechU Doctoral Presentation -March 2024 slides.pptxCapTechU Doctoral Presentation -March 2024 slides.pptx
CapTechU Doctoral Presentation -March 2024 slides.pptxCapitolTechU
 
The Singapore Teaching Practice document
The Singapore Teaching Practice documentThe Singapore Teaching Practice document
The Singapore Teaching Practice documentXsasf Sfdfasd
 
How to Add a New Field in Existing Kanban View in Odoo 17
How to Add a New Field in Existing Kanban View in Odoo 17How to Add a New Field in Existing Kanban View in Odoo 17
How to Add a New Field in Existing Kanban View in Odoo 17Celine George
 
Drug Information Services- DIC and Sources.
Drug Information Services- DIC and Sources.Drug Information Services- DIC and Sources.
Drug Information Services- DIC and Sources.raviapr7
 
Quality Assurance_GOOD LABORATORY PRACTICE
Quality Assurance_GOOD LABORATORY PRACTICEQuality Assurance_GOOD LABORATORY PRACTICE
Quality Assurance_GOOD LABORATORY PRACTICESayali Powar
 
How to Show Error_Warning Messages in Odoo 17
How to Show Error_Warning Messages in Odoo 17How to Show Error_Warning Messages in Odoo 17
How to Show Error_Warning Messages in Odoo 17Celine George
 
UKCGE Parental Leave Discussion March 2024
UKCGE Parental Leave Discussion March 2024UKCGE Parental Leave Discussion March 2024
UKCGE Parental Leave Discussion March 2024UKCGE
 
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptxSandy Millin
 
Clinical Pharmacy Introduction to Clinical Pharmacy, Concept of clinical pptx
Clinical Pharmacy  Introduction to Clinical Pharmacy, Concept of clinical pptxClinical Pharmacy  Introduction to Clinical Pharmacy, Concept of clinical pptx
Clinical Pharmacy Introduction to Clinical Pharmacy, Concept of clinical pptxraviapr7
 
Philosophy of Education and Educational Philosophy
Philosophy of Education  and Educational PhilosophyPhilosophy of Education  and Educational Philosophy
Philosophy of Education and Educational PhilosophyShuvankar Madhu
 
What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?TechSoup
 
3.21.24 The Origins of Black Power.pptx
3.21.24  The Origins of Black Power.pptx3.21.24  The Origins of Black Power.pptx
3.21.24 The Origins of Black Power.pptxmary850239
 
Benefits & Challenges of Inclusive Education
Benefits & Challenges of Inclusive EducationBenefits & Challenges of Inclusive Education
Benefits & Challenges of Inclusive EducationMJDuyan
 
Education and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptxEducation and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptxraviapr7
 
HED Office Sohayok Exam Question Solution 2023.pdf
HED Office Sohayok Exam Question Solution 2023.pdfHED Office Sohayok Exam Question Solution 2023.pdf
HED Office Sohayok Exam Question Solution 2023.pdfMohonDas
 
How to Solve Singleton Error in the Odoo 17
How to Solve Singleton Error in the  Odoo 17How to Solve Singleton Error in the  Odoo 17
How to Solve Singleton Error in the Odoo 17Celine George
 
In - Vivo and In - Vitro Correlation.pptx
In - Vivo and In - Vitro Correlation.pptxIn - Vivo and In - Vitro Correlation.pptx
In - Vivo and In - Vitro Correlation.pptxAditiChauhan701637
 

Último (20)

Easter in the USA presentation by Chloe.
Easter in the USA presentation by Chloe.Easter in the USA presentation by Chloe.
Easter in the USA presentation by Chloe.
 
How to Add Existing Field in One2Many Tree View in Odoo 17
How to Add Existing Field in One2Many Tree View in Odoo 17How to Add Existing Field in One2Many Tree View in Odoo 17
How to Add Existing Field in One2Many Tree View in Odoo 17
 
CapTechU Doctoral Presentation -March 2024 slides.pptx
CapTechU Doctoral Presentation -March 2024 slides.pptxCapTechU Doctoral Presentation -March 2024 slides.pptx
CapTechU Doctoral Presentation -March 2024 slides.pptx
 
The Singapore Teaching Practice document
The Singapore Teaching Practice documentThe Singapore Teaching Practice document
The Singapore Teaching Practice document
 
How to Add a New Field in Existing Kanban View in Odoo 17
How to Add a New Field in Existing Kanban View in Odoo 17How to Add a New Field in Existing Kanban View in Odoo 17
How to Add a New Field in Existing Kanban View in Odoo 17
 
Drug Information Services- DIC and Sources.
Drug Information Services- DIC and Sources.Drug Information Services- DIC and Sources.
Drug Information Services- DIC and Sources.
 
Quality Assurance_GOOD LABORATORY PRACTICE
Quality Assurance_GOOD LABORATORY PRACTICEQuality Assurance_GOOD LABORATORY PRACTICE
Quality Assurance_GOOD LABORATORY PRACTICE
 
How to Show Error_Warning Messages in Odoo 17
How to Show Error_Warning Messages in Odoo 17How to Show Error_Warning Messages in Odoo 17
How to Show Error_Warning Messages in Odoo 17
 
UKCGE Parental Leave Discussion March 2024
UKCGE Parental Leave Discussion March 2024UKCGE Parental Leave Discussion March 2024
UKCGE Parental Leave Discussion March 2024
 
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
 
Clinical Pharmacy Introduction to Clinical Pharmacy, Concept of clinical pptx
Clinical Pharmacy  Introduction to Clinical Pharmacy, Concept of clinical pptxClinical Pharmacy  Introduction to Clinical Pharmacy, Concept of clinical pptx
Clinical Pharmacy Introduction to Clinical Pharmacy, Concept of clinical pptx
 
Personal Resilience in Project Management 2 - TV Edit 1a.pdf
Personal Resilience in Project Management 2 - TV Edit 1a.pdfPersonal Resilience in Project Management 2 - TV Edit 1a.pdf
Personal Resilience in Project Management 2 - TV Edit 1a.pdf
 
Philosophy of Education and Educational Philosophy
Philosophy of Education  and Educational PhilosophyPhilosophy of Education  and Educational Philosophy
Philosophy of Education and Educational Philosophy
 
What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?
 
3.21.24 The Origins of Black Power.pptx
3.21.24  The Origins of Black Power.pptx3.21.24  The Origins of Black Power.pptx
3.21.24 The Origins of Black Power.pptx
 
Benefits & Challenges of Inclusive Education
Benefits & Challenges of Inclusive EducationBenefits & Challenges of Inclusive Education
Benefits & Challenges of Inclusive Education
 
Education and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptxEducation and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptx
 
HED Office Sohayok Exam Question Solution 2023.pdf
HED Office Sohayok Exam Question Solution 2023.pdfHED Office Sohayok Exam Question Solution 2023.pdf
HED Office Sohayok Exam Question Solution 2023.pdf
 
How to Solve Singleton Error in the Odoo 17
How to Solve Singleton Error in the  Odoo 17How to Solve Singleton Error in the  Odoo 17
How to Solve Singleton Error in the Odoo 17
 
In - Vivo and In - Vitro Correlation.pptx
In - Vivo and In - Vitro Correlation.pptxIn - Vivo and In - Vitro Correlation.pptx
In - Vivo and In - Vitro Correlation.pptx
 

Laser Communications

  • 2. Contents • Introduction • Block Diagram • Laser Transmitter And Receiver • Laser Transmitter • Receiver • Modulation • Gain Systems • Filters • Mounting System • Pointing • Why not Fiber Optics?? • Why not R.F?? • Advantages • Disadvantages • Applications • Conclusion • Reference
  • 3. Introduction • Laser communications systems are wireless connections through the atmosphere. • They work similarly to fiber optic links, except the beam is transmitted through free space. • While the transmitter and receiver must require line-of-sight conditions, they have the benefit of eliminating the need for broadcast rights and buried cables.
  • 5. LaserTransmitter and Receiver LaserTransmitter Receiver Optical fiber link Direct Link
  • 6. LaserTransmitter • 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.
  • 7. Receiver The receiver involves: • Telescope(‘antenna’) • Signal processor • Detector  PIN diodes  Avalanche Photo Diodes(APD)  Single or Multiple detectors
  • 8. Modulation : • AM : Easy with gas lasers, hard with diodes • PWM (Pulse Width Modulation) : Used by Ramsey in their kit • PFM (Pulsed FM) : Potentially the highest bandwidth (>100kHz)
  • 9. Gain Systems : Transmitter: • Maximum output power • Minimum divergence Receiver: • Maximum lens area • Clarity • Tight focus on detector
  • 10. Filters : • Sun shade over detector • Shade in front of lens • Detector spectral response • Colored filters  Absorb ~50% of available light  Difficult to find exact frequency
  • 11. Mounting System : • Mounts and stands need only be as accurate as beam divergence. • Good laser diodes will be 1-2mR (milli-radian) • A 32 pitch screw at the end of a 2' mount will yield 1mR per revolution. • Higher thread pitches allow shorter mounts which may be more stable (against wind, vibration, wires) • 1mR is 1.5' of divergence every 1000', 3' at 2000 ', etc.
  • 12. Pointing • GPS and Compass • Scopes and Binoculars • Strobe lights, large handheld floods, headlights • HTs to yell when laser light is seen at remote location
  • 13. Why not Fiber Optics?? • Not always possible to lay fiber lines :  Satellites  Combat zones  Physically/Economically not practical  Emergencies  Laser Communication being incorporated into fiber optic networks when fiber is not practical.
  • 14. Why not R.F?? • Bandwidth :  For laser communication is 100times larger than R.F. • Power :  In LC is directed at target, so much less transmission power  Also the power loss is less. • Size/Weight :  LC antenna is much smaller than R.F. • Security :  Due to low divergence of laser beam ,LC is more secure than R.F.
  • 15. 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.
  • 16. Disadvantages : For terrestrial applications, the principal limiting factors are: • Beam dispersion • Atmospheric absorption • Rain • Fog (10..~100 dB/km attenuation) • Snow • Scintillation • Interference from background light sources (including the Sun) • Shadowing • Pointing stability in wind • Pollution / smog
  • 17. Applications : • Laser light is used in optical fiber communications to send information over large distances with low loss. • Laser light is used in underwater communication networks. • Lasers are used in space communication, radars and satellites.
  • 18. Conclusion Laser communications offers a viable alternative to RF communications for inter satellite links and other applications where high-performance links are a necessity.