GRATING STRUCTURES IN 1.55pm InGaAsPhP STRAINED MQW GAIN-COUPLED DFB LASERS

In gain-coupled (GC) distributed-feedback (DFB) lasers of absorptive grating type, the device characteristics depend very much on the absorptive grating configuration such as duty cycle, layer thickness, conduction type, and material composition. We have fabricated 1 S5pm InGaAsP/InP strained multiple quantum well (MQW) DFB lasers having different absorptive grating thickness and different conduction type. Lasing characteristics of these lasers were compared in view of coupling coefficients and absorption saturation. Through net gain measurement, information useful for designing and optimizing the absorptive grating was obtained. I