Free Space Optical Communication
Mr.Boopathi Raj
""
ABOUT
Free Space Optics is a wireless communications technology that utilizes light to transmit data through the air similar to the way that fiber optics uses a fiber cable. This is a line-of-sight (LOS) communication in which data are sent through the air by using beams of light. The transfer speed of this technology is 100mbps to 10 Gbps and transmission loss is also very low.
History :
Alexander graham bell invents the first photophone which uses the same FSO technology in 1880. With the help of fiber optics military begin to research on FSO Companies begin to commercialize the FSO technology in 1990
How FSO works
» LASER is used for the transmission of the FSO, the equipment uses the intensity modulation of the LASER beam to send binary data in both directions through a transmitter/receiver coupled at each end. It uses pulses of light for the communication of data were ON=1 and OFF=0. First, the data is converted into 1s and 0s using a transducer and then the transmitter is used to project the light pulses.
» The receiver is then used to on the other end to receiver the pulses. Then the received signal converted back and sent through fiber or copper to network.
Why FSO? Why not bury more fibers?
Cost
Rights of Way
Permissions
Trenching
Time
Very Narrow & Directional Beams
» Beams only a few meters in diameter at a kilometer
» Allows very close spacing of links without interference
» No side lobes & Highly secure
» Efficient use of energy
Deployment Behind Windows
» Rapid installations without trenching and permission
» Direct connection to the end-user
» Bypasses the building owner
» No roof rights