SEMICONDUCTOR LASER DEVICE

摘要

A semiconductor laser device has a laser region including a semiconductor substrate, an active layer formed over the semiconductor substrate for emitting radiation when excited and a diffraction grating provided over or under the active layer for coupling the radiation. The device also is formed with a tuning region including an optical waveguide layer optically coupled to the laser region for waveguiding and constituting a part of the laser oscillation light path. An electrode is provided for injecting an electric current into the optical waveguide layer. A vertical end facet of the optical waveguide layer is provided with a high reflectivity structure for a reflectivity of 50% or above. The invention permits continuous wavelength tuning.