Monolithic adjustable gain-clamped semiconductor optical amplifier (AGC-SOA)

We report on a monolithic adjustable gain clamped semiconductor optical amplifier (AGC-SOA). The device consists of 2 tuneable gratings and a gain section and enables the gain of the SOA to be regulated without loss of saturated output power. Gain control is achieved by adjusting the wavelength overlap of two Distributed Bragg Reflector gratings positioned at either side of the active region which can be wavelength tuned by carrier injection. Gain clamped operation with adjustable gain over a range of 4 dB has been demonstrated. The device uses a 3-QW active layer optimised for high output power thus a maximum saturated output power of +21 dBm was obtained.