GaAs–AlGaAs DH Lasers with Buried Facet

A GaAs–AlGaAs DH laser with a buried facet into AlGaAs epitaxial layers is presented. This buried facet laser shows no facet degradation even when immersed in hot water. Recognizing the facet boiling experiment as an accelerated test of facet erosion, the AlGaAs facet of this laser seems to be highly reliable as compared with that of a conventional one. Another feature of the buried facet laser is found in its relatively narrow far-field pattern: Optical radiation power is concentrated within 50 deg., so that an efficient coupling to the fiber was achieved. These characteristics found in the buried facet lasers are advantageous for the light sources of high output power.