Abstract

Intensive research in coherent optical communications showed that several serious problems have to be solved before this technology becomes practical. Diversity techniques can provide remedies for several of these problems: large receiver bandwidth requirements; phase noise of the transmitter and local oscillator (LO) lasers; limited tuning range and intensity noise of local oscillators; and polarization fluctuations of the received signals. This paper summarizes the progress made in the various coherent diversity techniques during the last few years.

© 1989 Optical Society of America