Patent ID: 8174759

Claim:
An apparatus for controlling a gain of an optical amplifier (OA), the optical amplifier comprising an optically pumped gain medium, the apparatus comprising: a first multiplying digital-to-analog converter (MDAC) having: an analog input port for receiving a first electrical signal indicative of an optical power of input light entering the OA, a digital input port for receiving a digital feed forward (FF) gain control signal D FF , and an output port for outputting an analog FF signal that is proportional to the first electrical signal and to the FF digital gain control signal D FF ; a processor coupled to the digital input port of the first MDAC for generating the FF digital gain control signal DFF; an output circuit coupled to the output port of the first MDAC for outputting a pump control signal based at least in part on the analog FF signal for controlling a source of pump radiation of the OA.