High-power mid-IR type-II interband cascade lasers

Abstract

Type-II interband cascade (IC) lasers take advantage of the broken-gap alignment in type-II quantum wells to reuse electrons for sequential photon emissions for serially connected active regions. Here, we describe recent advances in InAs/GaInSb type-II IC lasers at emission wavelengths of 3.6 - 4 micrometers ; these semiconductor lasers have exhibited significantly higher differential quantum efficiencies and peak powers than previously reported. Low threshold current densities (e.g., approximately 56 /A/cm<SUP>2</SUP> at 80 K) and power efficiency exceeding 9% were observed from a mesa- stripe laser in cw operation. Also, these lasers were able to operate at temperatures up to 250 K in pulsed mode and 127 K in cw mode. We observed from several devices at temperatures above 80 K, slope efficiencies exceeding 1 W/A/facet, corresponding to a differential external quantum efficiency exceeding 600%. A peak optical output power of approximately 6 W/facet was observed from a type-II IC laser at 80 K.