Single-angled-facet laser diode for tunable external cavity lasers

Abstract

A tunable 980 nm external cavity laser based upon a single-angled-facet (SAF) semiconductor laser diode is demonstrated that does not require anti-reflection coatings or additional external mirrors. The SAF laser diode is comprised of a curved ridge waveguide that intersects the facet cleavage plane normally at one facet and at an angle at the other facet. A wide tuning range (70 nm) external cavity laser was obtained by coupling the output from the low reflectivity angled facet (R = 2 x 10-5) to a diffraction grating.