Controlled optical amplifier with optical circulator

摘要

Optical signals to be amplified (10) pass to an optical circulator (12). Signals circulate to a first port (I1) which has an interactive fibre optic amplifier guide (16) and pump (18). The pump is controlled by a service loop (20) which takes input power (I2) from the third port of the circulator. Signals from this port are filtered (22) and pass through a photorefractive network (24). The signal level is then monitored by an avalanche diode (26), converting the level to a voltage (28) which controls the pump level. Output signals from the third port circulate to the fourth output signal port(14).