Abstract: A distributed feed back semiconductor diode laser comprising a substrate of n-type conductivity gallium arsenide having a channel along one surface thereof between its end surfaces. A first clad layer of n-type gallium aluminum arsenide is on the surface of the substrate. The first clad layer fills the channel and has a planar surface. A thin active layer of undoped aluminum gallium arsenide is on the first clad layer and a spacer layer of p-type conductivity aluminum gallium arsenide is on the active layer. A grating layer of p-type conductivity aluminum gallium arsenide is on the spacer layer and has a second order grating therein which extends across the channel in the substrate. A second clad layer of p-type conductivity aluminum gallium arsenide is on the grating layer and a cap layer of n-type conductivity gallium arsenide is on the second clad layer. A p-type conductivity contact region extends through the cap layer to the second contact layer and is over the channel in the substrate.

Abstract: There is provided a super luminescent light emitting device comprising a semiconductor body including a central region and two opposing end regions extending a predetermined distance from the end faces. A gain guiding linear strip of material adjacent to a side of the active region extends between the end faces and is inclined along its longitudinal axis at a predetermined angle relative to a direction normal to at least one of the end faces. An optical beam path of the device has an optical axis of symmetry extending between the end faces parallel to the longitudinal axis of the strip. The beam path has end lateral boundaries at each of the end regions whose lateral carrier and optical confinement is determined by the gain guiding strip to allow light reflected at the end faces to be refracted out of the optical beam path.

Abstract: An optical fiber has a beveled end surface and a Bragg reflector grating formed on the end surface to form a single mode reflector for a semiconductor laser. A transmission fiber with a beveled end is fused to the beveled grating to form a continuous transmission line having an internal reflective grating.