An interferometric multiplexer

摘要

An interferometric optical multiplexer (10) for use in optical communication systems and especially for use in optical communication systems employing fibre optical amplifiers is disclosed. The interferometric optical multiplexer has two input ports (12,14), an output port (16) and an output monitoring port (18). The interaction of the input signals is monitored by a photodetector situated in the monitoring part (18). In conjunction with a feedback circuit (24) wavelength separation of signals input at ports (12,14) is ensured. The system can be used to pump an erbium doped optical fiber amplifier.