A single-pass single-amplifier polarization-insensitive semiconductor laser amplifier configuration

A novel single-pass single-amplifier polarization-insensitive optical amplifier configuration is proposed and used to solve the inherent polarization sensitivity of a compressively strained multiple-quantum-well (MQW) laser amplifier. The polarization-independent operation is obtained by single-passing the light with the preferred polarization through the amplifier chip. Therefore the light is decomposed into two mutually orthogonal polarizations and sent in opposite directions through the semiconductor laser amplifier. An analysis is presented that shows that the residual gain ripple and polarization sensitivity are sufficiently reduced when the residual facet reflectivities of the traveling-wave semiconductor laser amplifier are in the range below 10^-4