A novel all electrical scheme for laser amplifier gain control

The authors describe an automatic gain control technique which provides compensation for variations in laser amplifier gain caused by environmental effects and changes in system variables. The technique, which is applicable to a wide range of system line rates, is implemented using low speed electronics ( approximately 10 kHz) throughout with no additional optical components being required. It therefore offers the potential of excellent reliability combined with ease of implementation. The theoretical basis of the technique is discussed along with one possible practical implementation.