Optical PSK Transmission Experiment At 565Mbit/S Incorporating An Endless Polarisation Control System

The successful application of an endless polarisation control scheme was demonstrated by its use in a high sensitivity PSK heterodyne optical communication system. The synchronous demodulation of PSK signals was investigated and the practical implementation of a phase locked loop which is able to track the phase noise of optical signals is discussed. A large loop bandwidth is shown to be necessary and a loop filter of modified first order type was found to have advantages over a second order type. A synchronous demodulation system not using a phase locked loop is also proposed.