Ultra-low Reflectivity 1.5micron Semiconductor Laser Amplifier.

We report travelling wave 1.5micron semiconductor laser amplifiers with very low gain ripple. The average facet reflectivity is less than 5 x 10 sup -5 over a 170 angstrom interval. The minimum gain ripple is below the measurement accuracy, 0.2 dB, at 27.5 dB gain. When used as an optical pre-amplifier in a 4 Gbit/s receiver, a sensitivity of -34.3 dBm is achieved.