PSEUDOMORPHIC INGAAS-GAASP QUANTUM-WELL MODULATORS ON GAAS

Previous strain-relief p-i-n InGaAs-GaAs quantum well (qw) modulators have incurred surface striations upon growth due to defect formation, resulting in an optically rough surface. We present here a qw modulator on a GaAs substrate with InGaAs wells and GaAsP barriers which balance the strain in the wells so that the lattice does not relax, leading to much fewer defects, and an optically smooth surface. We obtain a transmission change from 60% to 80% at 1014 nm for a sample with a 1-mu-m thick intrinsic region.