We present a wavelength-tunable, external-cavity GaSb-based quantum-well laser operating near 3.2 μm. The laser setup consists of an intra-cavity grating in Littman-Metcalf configuration and a cascade pumped GaSb-based gain chip with a narrow-ridge waveguide. The narrow-ridge waveguide has a length of 2 mm and width of 7.5 μm. Cascade pumping is realized with three type-I quantum-wells, using one quantum-well per cascade stage. The laser provides continuous-wave output powers up to 8 mW and slope-efficiencies of 13 % at room temperature. Laser operation is demonstrated over a wavelength range of more than 300 nm, using continuous-wave and pulsed operation regimes.
Bibliographical note© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Funding: National Science Foundation (Grant Number: ECCS-1408126US), Basic Energy Sciences (Grant Number: DESC0012704), Alexander von Humboldt-Stiftung