Extended cavity quantum cascade laser with cavity resonator integrated grating filter

We report on an extended cavity quantum cascade laser based on a cavity resonator integrated grating filter (CRIGF) that acts as both cavity end-reflector and spectral selector. Stable, mode-hop free, single-mode emission around 2150 cm^-1 is obtained over large injection current ranges (more than 50 mA) with a typical threshold around 290 mA. A digital frequency tuning over more than 65 cm^-1 is obtained by changing the periodicity of the CRIGF ending the extended cavity.