1.3-mu m polarization-insensitive optical amplifier structure based on coupled quantum wells

We show that polarization-insensitive optical gain over a wide bandwidth ca n be realized in a coupled pseudomorphic multiple-quantum-well structure. T he barrier width is chosen such that heavy-hole subbands are grouped tightl y and light-hole subbands are widely separated in energy. For specific stra in conditions, the uppermost valence subbands, which have large occupation probability and strongly contribute to the gain, consist of a single light- hole subband and a group of coupled heavy-hole subbands, This arrangement g ives rise to balanced gains for the TE and TM polarizations. We present cal culated results for 1.3-mu m semiconductor optical amplifier structures bas ed on bands calculated in the framework of an eight-band k.p model. Two dif ferent material systems are examined, InAlGaAs and GaInAsP, on InP substrat es.