Ga In As ∕ Al As Sb quantum-cascade lasers operating up to 400K

Above room-temperature (T⩾400K) operation of GaInAs∕AlAsSb-based quantum-cascade lasers has been demonstrated. The lasers are based on vertical-transition active regions and consist of 25 periods of Ga0.47In0.53As∕AlAs0.56Sb0.44 active∕injection regions grown lattice-matched on InP substrates by molecular-beam epitaxy. They emit at a wavelength of λ∼4.5μm. For a device with the size of 18μm×2.8mm mounted substrate-side down with as-cleaved facets, a maximum peak power per facet of 750mW has been achieved at 300K and remains as high as 30mW at 400K. The characteristic temperature T0 of the threshold current density is 171K in the temperature range between 280K and 400K.