Distributed feedback interband cascade lasers with top grating and corrugated sidewalls

Abstract

Distributed feedback (DFB) interband cascade lasers (ICLs) with a 1st order top surface grating were designed and fabricated. Partially corrugated sidewalls were implemented to suppress high order lateral modes. The DFB ICLs have 4 mm long and 4.5 μm wide ridge waveguides and are mounted epi-up on AlN submounts. We demonstrated a continuous-wave (CW) DFB ICL, from a first wafer which has a large detuning of the gain peak from the DFB wavelength, with a side mode suppression ratio of 30 dB. With proper matching of grating feedback and the gain peak wavelength for the second wafer, a DFB ICL was demonstrated with a maximum CW output power and a maximum wall plug efficiency reaching 42 mW and 2%, respectively, at 25 °C. The lasing wavelengths of both lasers are around 3.3 μm at 25 °C.

The Interband Cascade Laser

“…More recently, Thorlabs reported DFB ICLs emitting at 3.3 µm that generated up to 42 mW of cw power with 2% WPE in a single spectral mode at 25 • C, with 30 dB SMSR [122]. They accomplished this by longitudinally segmenting the narrow ridge into alternating sections that were patterned with either a top grating for wavelength selectivity or corrugated sidewalls to suppress higher-order lateral modes.…”

Interband Cascade Laser Arrays for Simultaneous and Selective Analysis of C1–C5 Hydrocarbons in Petrochemical Industry

“…8,9 Various different techniques for the fabrication of spectrally single-mode devices were presented up to now. [10][11][12][13] In addition, IC devices have proven their robustness 14 making it possible for sensor systems to operate unattended for years. The major competing technologies are GaSb-based type-I transition diode lasers in the 3 to 4 µm regime [15][16][17] and the quantum cascade lasers which are able to cover the whole range of interest.…”