Optical Free Space Communication
#1

Introduction
With the improvements in semiconductors optical free space communication has become n attractive alternative to existing signal conducts as fibre or wireless (RF). It offers high data rates and is much less expensive than underground fibre. But there are a few restrictions, which may mean it remains an alternative. Many engineers are familiar with one of two successful existing technologies for data communication: (1) Guided wave (e.g. fibre optics) and (2) wireless free space communication (e.g. RF). Fibre optics offers extremely high bandwidths for high data rate, while RF communications offers the advantage of wireless connectivity and the ability to broadcast over a wide area. Optical free space communication fits into the 2nd group, but has some properties of the 1st. Many aspects are related to fibre optics with the difference, that the media is air and not fibers. Therefore are the required devices similar to those used with fibers.

The advantages of such a system are the following:
_ No need for digging up the roads
_ No radio frequency licenses are required
_ Bandwidth is equal or superior to fibre systems and much better than RF
_ Doesn't cause interference with existing electromagnetic equipment because interference on narrow band point-to-point connections is rather unlikely.

But there are as well some limitations:
_ Absorption (caused primarily by the water vapor and carbon dioxide)
_ Scattering (depends of the used wavelength and the number and size of scattering elements in the air e.g. fog)
_ Shimmer (due to a combination of factors, including atmospheric turbulence, air density, light refraction, cloud cover, and wind which cause a similar disturbance when a laser beam is transmitted through the atmosphere)
_ Moving building (although we are not aware of the movement, buildings often sway from side to side even settle into the ground causing offset to the laser beam and making the receiver laser receive less power)

Applications

Free space applications
Due to its properties optical free space communications is suited very well for providing high bandwidth to point-to-point connections. The attenuation characteristics of free space make inter-satellite connections a promising application for optical free space communication. Systems of this kind are already being deployed as a communications media in a number of key applications around the world.

Terrestrial applications
For terrestrial applications emerged a solution to the .last mile problem.. This consists in the fact that needs for bandwidth cannot be satisfied because the next fibre backbone is too far away. Laser links between the backbone and the user can provide quickly a high bandwidth much more cost effective than with other technologies. Due to the atmospheric effects on the propagation of light only short distance links can be established assuring a comparable bit error rate to fibre networks. With optical free space communication devices it's as well possible to replace lower speed wired lines between computer networks with fibre-like delay-free high bandwidth. It turned out as well that optical free space communication can be used to interconnect LAN's in campus or industrial environments in a reasonable way or to deploy temporary internet connection while the fibre installation can be done. Another application is to use laser links to bypass a broken data connection.

Military applications
There are not many information about military applications available. However there have been successful experiments to track moving objects with a laser beam as well for communication purposes using so called spatial light modulators.
Reply
#2
please read http://studentbank.in/report-freespace-o...ull-report and http://studentbank.in/report-optical-sat...ars-report and http://studentbank.in/report-future-sate...tion--5509 and http://studentbank.in/report-optical-sat...d-abstract for getting Laser Communication Systems or Free Space Laser Communications or future satellite communication seminar informations
Reply
#3
FREE SPACE OPTICAL COMMUNICATION
[attachment=17231]

WIRELESS CONNECTION
1. DISTRIBUTE DATA EVERYONE ,SECURITY IS JUDGED BY THE WEP
2. LICENCE REQ. TO PLANNING & COORDINATION
3. SUSCEPTIBLE TO RAIN ,LINK LENGTH
4. PP MICROWAVE PROVIDE HIGHER CAPACITY
Eg. LMDS
FIBER OPTIC BASED SOLUTION
1.FIBER OPTICS ARE TWO TYPE
A) SINGLE MODE [UPTO 60KM]


B)MULTI MODE [UPTO 2KM]
2)FIBER OPTICS ARE
SECURE
PROVIDE SPEED IN TERABYTE
PROTECTED FROM TAPPING
IMPOSIBLE TO DETECT LIGHT PULSE
FREE SPACE OPTICS
1)NO CABLES REQUIRED
2)TRANSMITTED IN ATMOSPHERE
3)REQUIRE LINE OF SITE AVAILABILITY


ADVANTAGES
FSO LASER BEAM CANNOT BE DETECTED WITH RF METER OR SPECTRUM ANALYSER
LOS PATH CANNOT BE INTERCEPTED EASILY
DATA CAN BE TRANSMITTED OVER AN ENCRYPTED CONNECTION
FREEDOM FROM LICENSING AND REGULATION
POSSBLE TO MOUNT INSIDE THE BUILDING


.ATMOSPHERE CHALLENGE
1.FOG
IT AFFECT ON NEAR INFRARED WAVELENGTH
AND HAVE SAME EFFECT AS RAINFALL HAVE ON THE RF
.PHYSICAL OBSTRUCTIONS
1.THESE CAN BE REMOVED BY WIDELY SPACED
REDUNDANT TRANSMITTERS AND LARGE RECEIVE OPTICS


.SCINTILLATION
THESE CAN BE REMOVED BY AUTOMATIC GAIN CONTROL CHAR.,TUNED RECEIVED
FILTERING,CLOCK RECOVERY PHASE LOCK
LOOP TIME CONSTANT
.SOLAR INTERFERENCE
IT CAN BE COMBATED BY
1.LONG PASS OPTICAL FILTER WINDO
2. OPTICAL NARROWBAND FILTERING







Reply
#4
to get information about the topic optical communication in space full report ,ppt and related topic refer the page link bellow

http://studentbank.in/report-optical-com...pace--3821

http://studentbank.in/report-optical-spa...cation-fso

http://studentbank.in/report-optical-fre...munication

http://studentbank.in/report-underwater-...munication

http://studentbank.in/report-optical-sat...ars-report
Reply

Important Note..!

If you are not satisfied with above reply ,..Please

ASK HERE

So that we will collect data for you and will made reply to the request....OR try below "QUICK REPLY" box to add a reply to this page
Popular Searches: optical communication ieee, free space optical communication seminar report, free space communication through the atmosphere, free space opticalcommunication, seminar report on free space optical communication, optical free space communication seminar, seminar optical communication in space,

[-]
Quick Reply
Message
Type your reply to this message here.

Image Verification
Please enter the text contained within the image into the text box below it. This process is used to prevent automated spam bots.
Image Verification
(case insensitive)

Possibly Related Threads...
Thread Author Replies Views Last Post
  Optical Computer Full Seminar Report Download computer science crazy 46 66,338 29-04-2016, 09:16 AM
Last Post: dhanabhagya
  Mobile Train Radio Communication ( Download Full Seminar Report ) computer science crazy 10 27,938 01-05-2015, 03:36 PM
Last Post: seminar report asees
  Mobile Train Radio Communication Electrical Fan 5 14,707 11-03-2015, 07:27 PM
Last Post: Guest
  space mouse full report computer science technology 6 8,729 24-02-2014, 10:14 PM
Last Post: Guest
Question Space-time Adaptive Processing (STAP) computer science crazy 2 3,146 16-10-2013, 03:09 PM
Last Post: Guest
  3D-OPTICAL DATA STORAGE TECHNOLOGY computer science crazy 3 8,502 12-09-2013, 08:28 PM
Last Post: Guest
  eye gaze communication system full report seminar topics 19 35,384 26-07-2013, 01:45 PM
Last Post: computer topic
Star Optical Satellite Communication (Download Full Report And Abstract) computer science crazy 8 19,947 26-04-2013, 11:52 AM
Last Post: computer topic
  Free Space Laser Communications computer science crazy 4 7,005 06-02-2013, 12:02 AM
Last Post: Guest
  LASER Communication seminar projects crazy 8 14,694 24-01-2013, 02:57 PM
Last Post: seminar details

Forum Jump: