High Performance Interband Cascade Lasers With Room Temperature Lasing Wavelengths Near 3.3 μm

We report significant advancements of interband cascade lasers (ICLs) with hybrid cladding layers. These 6-stage hybrid-cladding ICLs were able to lase in pulsed modes at temperatures up to 421 K, the highest ever reported among ICLs. The lasing wavelength was near <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.3~\mu $ </tex-math></inline-formula>m at 300 K with a pulsed threshold current density of 114 A/cm2, the lowest for ICLs with similar wavelengths. Also, they achieved a high voltage efficiency of ~82% and a record-low threshold input power density of 312 W/cm2 at 300 K. Facet-uncoated narrow-ridge ICLs operated in continuous wave (CW) mode at temperatures up to 364 K (91°C), which is more than 20 K higher than the previous record for epi-up mounted ICLs. The obtained CW threshold current density of 205 A/cm2 at 300 K is similar to the previous record (~200 A/cm2 at 300 K) achieved by a superlattice-cladding 10-stage ICL with emission near the long-held optimal wavelength of ICLs at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.6~\mu $ </tex-math></inline-formula>m. Also, these ICLs at 300 K delivered CW output power of 25 mW/facet at 160 mA with substantially improved external quantum efficiency over previous ICLs at similar wavelengths.