Temperature-insensitive intersubband-transitions in InGaAs/AlAsSb multiplequantum well designed for optical communication wavelength

We present the first experimental evidence on temperature independent inter subband transitions in InGaAs/AlAs/AlAsSb/InP quantum well (QW) structures tailored for optical communication at 1.55 mum. The relative strength and p eak wavelengths of intersubband transitions between the four levels in the coupled double QW's change with temperature, due to the carrier redistribut ion between the miniband states in the conduction band. The temperature ins ensitivity is observed for the conduction subband electronic transitions be tween the ground and the uppermost confined subband states in asymmetricall y coupled double QW. The temperature dependence of intersubband transitions in coupled and uncoupled systems has been compared and the coupled QWs has been observed to exhibit an extremely small intersubband-transition temper ature gradient of 2.3 x 10(-3) meV/K compared to 0.155 meV/K in uncoupled Q W's.