Frame synchronisation for optical fibre digital PPM

An appropriate random variable is incorporated into an original model to represent the stochastic data sequence encoded. It is shown that unlike free space PPM, optical fibre exhibits a discrete component at the frame rate that can be used for synchronisation. The modulation index can be employed to enhance this component. Consideration is given to the nature of the dispersive optical fibre channel. Original practical results measured on an experimental system are shown to be in agreement with the theoretical predictions. The paper concludes by identifying a set of PPM parameters that optimises frame synchronisation