In As ∕ Al Sb quantum cascade lasers emitting at 2.75–2.97μm

Abstract

Quantum cascade lasers emitting at wavelengths as short as 2.75μm at 80K and 2.97μm near room temperature are demonstrated. Despite the small band gap of InAs, the laser performances are not affected by interband absorption. No effect of the L valley in InAs on quantum cascade laser performances is observed at 80K in these devices.

Temperature dependence of 4.1 μm mid-infrared type II “W” interband cascade lasers

“…We also find that the threshold current density dependence on temperature can be fitted with a single exponential function over a wide temperature range with a characteristic temperature, T 0 , of 45 K. The relatively high temperature sensitivity in these devices is attributable to the large non-radiative current contribution coupled with non-pinning of the carrier density above threshold. 4), shorter wavelength QCLs tend to suffer from inadequate conduction band offset and inter-valley carrier scattering, which degrade their high temperature performance. 4,5 InAs/GaInSb type-II "W" interband cascade lasers (ICLs) using spatially indirect transitions 6 and resonant interband carrier tunnelling 7 as studied in this work have yielded promising results in the 2.9 lm to 4.2 lm range 6,8 and recently operated in cw mode at ambient temperature.…”

“…4), shorter wavelength QCLs tend to suffer from inadequate conduction band offset and inter-valley carrier scattering, which degrade their high temperature performance. 4,5 InAs/GaInSb type-II "W" interband cascade lasers (ICLs) using spatially indirect transitions 6 and resonant interband carrier tunnelling 7 as studied in this work have yielded promising results in the 2.9 lm to 4.2 lm range 6,8 and recently operated in cw mode at ambient temperature. 8 Generally, the dominant non-radiative recombination process in interband MIR lasers is Auger recombination.…”

High temperature operation of short wavelength InAs-based quantum cascade lasers

“…The maximum operation temperature of InAs/AlSb QCLs emitting at 3.33 μm at RT (3.22 μm at 80 K) reaches 400K 10 but it decreases at shorter wavelengths down to 140 K in the 2.75 μm lasers. 8 The drop in the maximum operation temperature in these lasers was accompanied with a decrease in the maximum available current from 9 to 3.5 kA/cm 2 despite nearly the same doping level in all the structures. The goal of this study was to reach high temperature operation of InAs/AlSb QCLs with λ RT shorter than 3.3 μm.…”

“…On the other hand, the weak coupling of the injector states, probably responsible for the small available current in lasers reported in ref. 8, can be avoided by optimization of the design. In this work we modified the QCL design to lift this limitation in order to improve the operation temperature of short wavelength QCLs.…”

“…8 by specific features of the used designs. The last injector level in the short wavelength QCLs was not sufficiently coupled with preceding injector states thus reducing the available current, which, in turn, limited the laser operation temperature.…”