3.3 mu m Distributed Feedback Interband Cascade Lasers with Top Grating

Here we present the design and results of distributed feedback (DFB) interband cascade lasers (ICL) with 1st order top surface grating. A partially corrugated sidewall waveguide was designed and implemented to suppress high order lateral modes. The DFB ICLs have 4mm long cavities and 4.5 mu m wide base line ridge waveguide, and are mounted epi-up on SiC submounts. Continuous-wave (CW) operation of the DFB ICLs was demonstrated. The lasing wavelengths re around 3.3 mu m at 25 degrees C, and the measured side mode suppression ratio is 30 dB. The best device with low detuning of gain peak and DFB Bragg wavelength showed a maximum output power and a maximum wall plug efficiency of 46 mW and 2 %, respectively, at 25 degrees C.