Abstract
The receiver performance of optical Costas PLL's is evaluated accounting for the effects of laser phase noise, shot noise and the data-to-phaselock crosstalk induced by signal waveform distortion. In contrast to the conventional discussion in which the received signal data is a sequence of square pulses, this paper for the first time investigates the problem encountered in BPSK homodyne communication systems with Costas PLL's as the received signal data is not a sequence of square pulses but is a sequence of distorted pulses. The signal waveform distortion induces additional amount of phase error variance and henceforth an increase in bit-error rate, resulting in a more stringent laser linewidth requirement. The laser linewidth requirement is evaluated here taking into account such an effect of signal waveform distortion.