Electrically tunable cascaded mid-IR type II light source

We propose a novel design of an electrically tunable type II mid-IR light source based on a InAs/AlSb/GaInAsSb/GaInSb heterostructure. The design combines the advantages of strong wavelength tuning due to the linear Stark effect and the presence of separate charge accumulation layers, which enables laser wavelength tuning without a change of the optical loss. Experiment shows a blue shift of the electroluminescence (EL) line at increasing bias current, commensurate with that expected form the linear Stark effect. The laser generation was observed at higher currents. The EL wavelength shifts from 2.79μm to 2.38μm (∼ 80meV) at T=80K as the bias current increases from 97mA to 418mA, which provides the record combination of the wide tuning range and low relative change of the bias current.