Quantum-cascade distributed-feedback lasers (QC-DFB) with a grating close to the active region are reported. Feedback is provided by the grating in a refractive index-dominated coupling scheme. Reliable single-mode emission at λ cm ≈ 5.4 μm with a side-mode suppression ratio (SMSR) ≈30 dB is observed. The laser is continuously tunable over 40 nm with a coefficient of Δλ/ΔT ≈ 0.37 nm/K in the temperature range from 200 K to 300 K. Comparison with Fabry-Perot QC lasers shows an overall improved performance of QC-DFB lasers.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering
- Distributed-feedback laser
- Unipolar semiconductor laser