Enhanced performance of InAs-based interband cascade lasers emitting between 10–13 µm

Abstract

Interband cascade lasers (ICLs) based on the type-II quantum well (QW) active region have attracted much attention for a range of practical applications in the mid-infrared (MIR) due, in part, to their low power consumption. However, extending the operating wavelength of these ICLs into the long-wave infrared (LWIR) region presents several challenges including the reduced thermal conductivity of the optical cladding layers and the diminished wavefunction overlap in the type-II QW. One solution to alleviate the former concern is to use InAs-based ICLs. To solve the latter problem, InAs0.5P0.5 barriers are introduced in the active region, which lowers the electronic energy level and allows for the InAs well width to be reduced at longer emission wavelengths. Here the advancement of long wavelength ICLs, made from four new InAs-based ICL wafers grown by molecular beam epitaxy (MBE), is reported. These ICLs lased in the wavelength range from 10 to 13 µm and showed significantly improved performance compared with previous ICLs, including the first demonstration of broad-area devices operating in continuous wave (cw) mode beyond 12 µm. These ICLs exhibited substantially increased output powers with reduced threshold voltages (Vth) and current densities (Jth). They operated at temperatures up to 40 K higher than previous ICLs at similar wavelengths.

Interband cascade lasers with advanced waveguides operating in the 3 to 4 μm wavelength region

“…cladding layer with the n+-type doped InAs plasmon cladding, enabled enhanced device performance by reducing the free-carrier loss and yielding improved optical confinement within the cascade active region 18 . This advanced waveguide was later shown to improve performance in long wavelength InAs-based ICLs emitting between 10 and 13 μm 19 , 20 and was also explored in GaSb-based ICLs operating between 3.8 and 6.1 μm 21 , 22 where the plasmon-enhanced cladding layer in the latter is composed of n+-type doped InAs0.91Sb0.09. Here, we report a study of several GaSb-based ICLs that incorporate this advanced waveguide structure 23 and emit in the 3 to 4 μm wavelength region.…”

Room temperature operation of single mode GaSb‐based DFB interband cascade lasers beyond 6.1 µm

“…While the performance sweet spot for ICLs is between 3 and 4 µm, the upper wavelength limit has recently been pushed further [7,8]. With InAs-based ICLs emission wavelengths up to 14 µm at cryogenic temperatures in pulsed mode are possible [9,10]. In the case of GaSb-based ICLs, the longest pulsed emission wavelength reported so far is 6.8 µm for broad area devices [11].…”