OPTICAL COMMUNICATIONS SYSTEM

摘要

An optical network includes optically pumped waveguide amplifiers (23). A supervisory signal uses the amplifier's pump wavelength (23), e.g. APPROX 1480 nm if EDFAs are used. Substandard pump diodes may be used to generate the supervisory signal. A repeater station for the network includes an optically pumped waveguide amplifier (23) and a bypass route (27, 28, 29, 30, 31) for supervisory signals. In a described example the bypass route comprises an optical supervisory signalling means (31), an optical receiver (29), a first wavelength division multiplexer (27) for coupling a supervisory signal from a transmission medium and applying it to the optical receiver, processing means (30) for processing supervisory signal data received by the receiving means and controlling the optical supervisory signalling means to generate a further supervisory signal, and a second wavelength division multiplexer (28) for coupling the further supervisory signal into the transmission medium, wherein the first and second wavelength division multiplexers are arranged one on either side of the waveguide amplifier.