Direct demodulation of optical binary fsk signals

摘要

A self heterodyne direct demodulation arrangement for differentially encoded optical binary FSK signals comprising a two-path optical interferometer (23) having a path unbalance optical delay (21) not exceeding FSK bit period, means for applying the FSK signals to both paths of the interferometer, and means for detecting (26-1, 26-2, 28) the optical beat frequency of the interferometer output.