High-performance, homogeneous broad-gain quantum cascade lasers based on dual-upper-state design

Abstract

A broad-gain quantum cascade laser design with dual-upper-state is proposed to clarify its own feasibility. Devices employing the proposed active region design exhibit homogeneously wide (>330 cm−1) electroluminescence spectra of which shapes are insensitive to voltage changes. A buried heterostructure laser, emitting at λ∼8.4 μm, demonstrates a high continuous-wave output power of 152 mW together with a high constant slope efficiency of 518 W/A at room temperature. In addition, the device performance is observed to be very insensitive to temperature change; T0-values of ∼306 K and constant slope efficiency over the wide temperature range, 280–400 K.