InAs-Based Single-Mode Distributed Feedback Interband Cascade Lasers
InAs-based single-mode distributed feedback (DFB) interband cascade (IC) lasers were investigated. The DFB grating was patterned using interference lithography to etch the cladding-free upper separate confinement layer of the IC laser structure. Single-mode emission with a side mode suppression ratio of ~ 30dB was obtained in continuous wave operation at temperatures up to 180 K near 4.5 μm . A total tuning range of 16 nm could be achieved for a single device, with typical temperature- and current-tuning rates of 0.4 nm/K and 0.016 nm/mA, respectively. The impact of the DFB grating on device performance was evaluated and discussed in comparison with Fabry-Perot lasers.