Third-order photonic-crystal distributed-feedback quantum cascade lasers

Abstract

We demonstrate room-temperature operation of broad-area edge-emitting photonic-crystal distributed-feedback quantum cascade lasers at λ∼4.6μm. The lasers use a weak-index perturbed third-order photonic-crystal lattice to control the optical mode in the wafer plane. Utilizing this coupling mechanism, the near-diffraction-limited beam quality with a far-field profile normal to the facet can be obtained. Single-mode operation with a signal-to-noise ratio of about 20dB is achieved in the temperature range of 85–290K. The single-facet output power is above 1W for a 55μm×2.5mm laser bar at 85K in pulsed mode.