Tunable Wide-aperture semiconductor laser with an external waveguide grating mirror

An external cavity with a waveguide-grating mirror is proposed for a wide-aperture semiconductor laser. The emission spectra of a laser diode in the cavity were studied for the regimes of collinear and noncollinear incidence of radiation on the waveguide-grating mirror. A substantial narrowing of the emission spectrum, down to 0.1 nm, and continuous tuning of laser radiation within the range from 10 to 18 nm were demonstrated.