Significant progress has been made in the demonstration of single-channel coherent optical receivers,1 and the emphasis in research is beginning to turn toward multichannel systems. Closely spaced channels are desirable to take maximum advantage of the available bandwidth of single-mode fiber and also because of practical considerations such as the limited tuning range of local oscillator lasers. It is, therefore, important to understand the performance limitations of various coherent systems as the channel spacing is reduced. This paper is the first to address theoretically the issues of bit-error-ratio performance and sensitivity penalties due to adjacent channel interference in ASK, PSK, and FSK optical communication systems.
© 1988 Optical Society of AmericaPDF Article