Single-mode interband cascade lasers emitting below 2.8 μm

Abstract

In this work, single-mode distributed feedback (DFB) interband cascade laser (ICL) devices with record short wavelength emission below 2.8 μm are presented. Pulsed measurements based on broad area laser devices with a cavity of 2 mm length and 150 μm width showed threshold current densities of 383 A/cm2 at T = 20 °C and a characteristic temperature T0 of 67 K. Fabricated DFB devices were operated in continuous wave mode at room temperature, with threshold currents of 57 mA and demonstrated side mode suppression ratios of larger than 25 dB. The devices showed current tuning ranges of 7 nm and total (including drive current and temperature) tuning ranges of 12 nm, with respective tuning rates of 21 nm/W, 0.13 nm/mA and 0.29 nm/K. Using the full spectral gain bandwidth of the underlying ICL material, single-mode DFB emission was observed within a wavelength range of 150 nm utilizing different DFB grating periods.

Wavelength Dependence of Efficiency Limiting Mechanisms in Type-I Mid-Infrared GaInAsSb/GaSb Lasers

“…Currently high performance type-II lasers occupy the spectral niche between type-I lasers and QCLs. However, the wavelengths accessible by type-II lasers has expanded, recently achieving operation < 3 μm [27]. As in conventional diode lasers, photon emission is achieved through the radiative recombination of electrons and holes.…”

InAs-based distributed feedback interband cascade lasers

“…13 Several approaches have already been realized to achieve a single mode emission on GaSb-based ICL devices in the wavelength range between 2.8 lm and 5.2 lm. 5,[14][15][16][17][18] While early single mode devices were based on corrugated sidewall gratings or top gratings, more recently distributed feedback (DFB) lasers using lateral metal gratings were demonstrated on the GaSb-based ICL material. 18 In these devices, a metal grating is placed on both sides of the ridges in the GaSb-separate confinement layer (SCL) directly beneath the active region.…”

“…On GaSbbased ICLs, room-temperature cw operation has already been demonstrated in the wavelength range between 2.8 lm and 5.6 lm. [5][6][7][8] At longer wavelengths, the low thermal conductivity and the complex growth of the superlattice claddings become increasingly difficult, as the thickness of the claddings has to be increased to avoid mode leakage into the substrate. By using highly doped InAs plasmon claddings in ICLs grown on InAs substrates, a higher thermal conductivity and a simplified growth can be achieved, 9 allowing such devices to extend the wavelength range covered by ICLs.…”

Polarization-independent gain in mid-infrared interband cascade lasers

“…1,2 Over the past couple of years, there has been achieved a significant progress in the performance of ICLs on GaSb substrates, especially in the 2.8-5.6 µm wavelength region. [3][4][5][6][7] This has been stimulated by increasing importance of ICLs in many applications, including environmental pollution monitoring, medical diagnostics, infrared countermeasures, laser surgery and gas leakage detection. [8][9][10][11] Furthermore, ICLs have several advantages, when compared to more common diode lasers or quantum cascade lasers (QCLs).…”

“…ICLs require only 5-10 cascades to reach similar working conditions. [5][6][7] The polarization selection rules for optical transitions in quantum well (QW) structures determine the contribution of transverse electric (TE) and transverse magnetic (TM) polarizations in in-plane emission, depending of its origin (electron-heavy hole or electron-light hole radiative recombination). One of the interesting designs is a polarization-independent emitter in the mid-infrared wavelength regime.…”