Nonlinear absorption and wave mixing in InGaAs/GaAs strained layer MQWs at 1.06 µm wavelength

Abstract

There are a number of advantages of using a multiple quantum well (MQW) for nonlinear optical devices at 1.06 µm wavelength.1 InGaAs/AlAs MQWs are good candidates for this wavelength. We fabricated these MQWs with different structures by using the MBE technique. The parameters of the samples were selected to have the exciton peak near 1.06 µm. One sample was grown on an InGaAs buffer layer to relieve the strain. Others were grown on GaAs substrate. After the processing of the samples, the linear absorption spectrum was measured with a commercial infrared spectrometer. The results showed the exciton peak at 1.06 µm. We performed the nonlinear absorption experiments by using different input intensities up to 10 kW/cm2. The saturation intensity of the samples was observed around 1000 W/cm2. The saturation is due to the band filling of the continuum states and exciton bleaching. We also performed four-wave mixing using these samples by detecting the diffracted beam. The signal showed strong dependence on the pump intensity.