Electrically pumped photonic crystal distributed feedback quantum cascade lasers

Abstract

We demonstrate electrically pumped, room temperature, single mode operation of photonic crystal distributed feedback (PCDFB) quantum cascade lasers emitting at λ∼4.75μm. Ridge waveguides of 100μm width were fabricated with both PCDFB and Fabry-Pérot feedback mechanisms. The Fabry-Pérot device has a broad emitting spectrum and a double lobed far-field character. The PCDFB device, as expected, has primarily a single spectral mode and a diffraction limited far field characteristic with a full angular width at half maximum of 2.4°. This accomplishment represents the first step in power scaling of single mode, midinfrared laser diodes operating at room temperature.