JEE Main & Advanced Physics Communication System / संचार तंत्र Optical Communication

(1) The use of optical carrier waves for transmission of information from one place to another is called optical communication.

(2) The useful optical frequency range is \[{{10}^{12}}\,Hz\] to \[{{10}^{16}}\,Hz\] which is very high as compared to radio and microwave frequencies\[({{10}^{6}}Hz{{10}^{11}}Hz)\].

(3) The information carrying capacity \[\propto \] bandwidth µ frequency of carrier wave. So optical communication is better than others. (because of high frequency).

(4) Basic setup of optical communication shown below

(5) Light emitting diodes (LED) and diode lasers are preferred for optical source. LED's are used for small distance transmission while diode laser is used for very large distance transmission.

(6) In order to transmit information signal via an optical communication system, it is necessary to modulate light with the information signal.

(7) The optical signal reaching the receiving end has to be detected by a detector which converts light into electrical signals, So that the transmitted information may be decoded. Semiconductor based photo-electors are used