Heterodyning and nonlinear QWIPs

Summary form only given. We have carried out several experiments on device optimization for high absorption, on heterodyne detection up to 82 GHz, and on various nonlinear effects using GaAs/AlGaAs QWIPs. Near-ideal (/spl sim/100%) absorption quantum efficiency and room-temperature operation have been achieved, with specially designed devices having a large number of quantum wells and high well doping densities. Record-high frequencies up to 82GHz have been reached in heterodyne detection. Nonlinear effects caused by nonuniformity in potential distribution and laser intensity variation have been studied. Auto-correlation using a two-photon process has been demonstrated.