High device yield and performance of InGaAsP MQW DFB lasers with absorptive grating

AR/HR-coated, loss-coupled, InGaAsP multiple quantum well distributed feedback lasers emitting at 1.55 mum are reported, indicating a high device yield of ~66% for the quarter of a two-inch wafer and a good reliability as long as 5000 h operation at 85degC with a constant power of 5 mW. The high device yield was achieved by the automatically buried InAsP absorptive grating formed during the heat-up process on InP corrugations and the uniform surface-facing upward wet chemical etching process.