Incompletely modulated PSK signal reception using modified balanced optical phase-locked loop

A homodyne optical communication system using incomplete phase modulated PSK signal is considered. The phase-error variance of the system critically depends on the phase deviation parameter between the two transmitted bits. Also, optical phase-locked loop (OPLL) has finite loop-delay. All these venomous effects put constraints on the performance of a conventional OPLL based PSK receiver. A modified balanced OPLL based homodyne PSK signal reception system overcome some of these limitations, offers a much improved tracking performance and also provides more relaxed line-width requirement, improved tolerance and performance against delay.