High-power, continuous-wave, current-tunable, single-mode quantum-cascade distributed-feedback lasers at λ ≅ 52 and λ ≅ 795 µm

Quantum-cascade distributed-feedback lasers with high-power, continuous-wave (cw), tunable, single-mode emission are reported. The emission wavelengths are near 5.2 and $7.95 \mathit{\mu }\mathrm{m}$. The lasers are operated at liquid-nitrogen temperature and above. A maximum output power of $>100 \mathrm{mW}$ is obtained per facet at 80 K for both wavelengths, which is the result of careful positioning of the peak gain with respect to the Bragg wavelength. Continuous tuning with either heat-sink temperature or cw current is demonstrated. The tuning coefficients are $0.35 \mathrm{nm}/\mathrm{K} \left(5.2 \mathit{\mu }\mathrm{m}\right)$ and $0.51 \mathrm{nm}/\mathrm{K} \left(7.95 \mathit{\mu }\mathrm{m}\right)$ for thermal tuning and vary from 20 to $40 \mathrm{nm}/\mathrm{A}$ for tuning with current. The lasers are being used in high-resolution and high-sensitivity gas-sensing applications.