Single Laser Light Source Multi-Channel PSK Optical Communication
J. Iqbal Syed, H.B. Ahmad Mohamed, A.M. Ramzia Salem
Two light waves which have the same wavelength and the same plane of polarisation can interact with each other and produce an interference pattern only if the path difference between two waves is less than the coherence length. It also implies that if the path difference is more than the coherence length, then the waves will not create an interference pattern or decoding of a signal will then not be possible. Using this property, it was demonstrated that more than one channel can be transmitted as long as the difference in their path lengths is more than the coherence length of the light source used.