Gain-coupling distributed feedback type semiconductor laser device

摘要

A gain-coupling distributed feedback type semiconductor laser device realizing a high light output power without causing an increase in the threshold current or a reduction in the emission efficiency, specifically a gain-coupling distributed feedback type semiconductor laser device comprised of a diffraction grating at least at part of the inside of a cavity and having a gain or loss periodically changing, a reflectance of one end surface (front facet) of the cavity being not more than 3% and the reflectance of the other end surface (rear facet) being larger than the reflectance of that one end surface and not more than 60%, such a gain-coupling distributed feedback type semiconductor laser device wherein the length of said cavity is at least 400 mum, and in particular such a gain-coupling distributed feedback type semiconductor laser device of an absorbing diffraction grating type.