Interband cascade Lasers with AlGaAsSb cladding layers emitting at 33 µm

Abstract

We investigate the impact of the growth conditions of AlGaAsSb cladding layers on the properties of interband cascade lasers (ICLs). For an optimized structure emitting at 3.3 µm, we achieve an internal quantum efficiency of 65% per stage in good agreement with conventional ICL using InAs/AlSb superlattice cladding layers, in spite of internal losses of 15 cm −1 due to higher optical losses in the n-type AlGaAsSb alloys. Finally, we report a narrow ridge ICL emitting at 3.33 µm operating in continuous wave up to 80°C that produces 1 mW/uncoated facet at 80°C, 10 mW at 40°C and more than 12 mW at 20°C.

The Interband Cascade Laser

“…While the ICL's active region can in principle comprise the entire waveguide core, this would require more stages than are generally optimal from other standpoints that will be discussed below [64,73]. Therefore, it is useful to view the waveguide as constructed from the following basic building blocks: (1) the active core, (2) n-doped optical claddings, most commonly comprised of InAs/AlSb short-period superlattices (SLs), although bulk alloys such as AlGaAsSb provide an alternative [74,75], and n-InAs may be employed when the ICL is grown on an InAs substrate [76]; (3) lightly n-doped GaSb separate-confinement layers (SCLs); and (4) transition SLs that separate the other three regions from each other, and from the GaSb substrate/buffer and n + -InAs(Sb) top contact. The transition SLs reduce parasitic voltage drops that would occur at the otherwise abrupt heterointerfaces between adjacent regions with very different conduction-band offsets (CBOs).…”

Mid-infrared, long-wave infrared, and terahertz photonics: introduction

“…The contributed papers exhibit several significant advances in the generation of long-wavelength light. These advances expand the envelope for long-wavelength optical sources by increasing the spectral limits of sources [1] and investigating and improving source performance [2,3,4]. T. Du et al [1] present their work on a germania-fiber short-pulsed Raman laser emitting at 2.166 µm with tunable pulse widths of 0.9 to 4.4 ns and pulse energies up to 12.15 nJ.…”

“…The paper also reports single-longitudinal-mode output with powers up to 1.02 W using a second Ho:GTO crystal with the same parameters as the crystal in the ring laser as a power amplifier. D. A. Diaz-Thomas et al investigate the performance of interband cascade lasers (ICLs) emitting at 3.3 µm that employ bulk claddings of AlGaAsSb rather than superlattice claddings of InAs/AlSb, which are typically used in ICLs [2]. Their approach leverages AlGaAsSb as a low-index cladding material to improve confinement, reduce the burden on ICL growth, and improve thermal conductivity of the cladding.…”

Progress in Interband Cascade Lasers: From Edge Emitting Lasers to VCSELs

“…As a first step towards the fabrication of hybrid GaAs/GaSb IC-VCSELs, we started our investigations by ensuring that laser operation from large-area edge-emitting lasers could be achieved using the chosen 7-stage quantum-well/injection IC active region whose design is fully described in [6]. Two sets of devices were grown and fabricated.…”

“…As illustrated in Figure 1, the reference structure layout relied on conventional Te-doped AlSb/InAs cladding layers while the second used a metamorphic Te-doped GaAs upper cladding to study the influence of the latter on the device performance. Episide-up-mounted 4-mm-long broad-area lasers with a stripe width of 100µm were fabricated using the established process reported in [6] with an upper Ti/Au metallic contact and a Pd/AuGeNi back contact.…”