Nonlinear Optical Absorption In InGaAs/InP And InGaAs/InA1As Multiple Quantum Well Structures

We have measured the intensity dependence of the room temperature optical transmission of an In .53 Ga .47 As/InP multiple quantum well (MQW1) and an In .53 Ga .47 As/In .52 A1 .48 As multiple quantum well (MQW2) from 1.5μm to 1.7μm. The absorption is calculated from the transmission taking into account the wavelength dependence of the reflection coefficients. At the edge of tlAe 1H-1C transition absorption band the absorption is found to fall by 1/2 if the intensity is 16kWcm -2 and 15kWcm -2 at the surface of MQW1 and MQW2 respectively and is completely saturated at intensities exceeding 10 7 Wcm -2 , showing no nonsaturable absorption. A theoretical model is described, which fits the intensity dependence of the absorption right up to saturation at two wavelengths with an assumed carrier lifetime of 0.66ns for MQW1 and 0.75ns for MQW2.