Abstract: High power semiconductor lasers which operate in the fundamental lateral and transverse mode are disclosed. Fundamental transverse mode behavior is well known by virtue of using a thin active layer. Fundamental lateral mode behavior in a wide double hetero-structure laser is achieved by selectively enhancing losses in the higher order lateral modes. Alternatively, a distributed feedback structure such as a grating may be used to achieve fundamental lateral mode operation in a wide double hetero-structure semiconductor laser.

Abstract: A buried hetero-structure laser diode is disclosed. The buried hetero-structure is formed by growing a double hetero-structure on a substrate. The double hetero-structure comprises two cladding layers spaced apart by a narrow bandgap active layer. Two spaced apart channels are etched in the double hetero-structure down to the lower cladding layer to define a mesa therebetween. Current blocking layers are deposited in the channels and on the portions of the double hetero-structure located outside the channels. The liquid phase epitaxy growth conditions are such that while the blocking layers are deposited in the channels and outside the channels, the upper cladding layer portion of the mesa is being melted back. Thus, the ends of the blocking layers touching the melted back mesa are separated from the active layer portion of the mesa by a thickness substantially less than the thickness of the upper cladding layer as measured in the regions outside the channels.

Abstract: A semiconductor laser diode comprising first and second parallel optically coupled waveguides is disclosed. The waveguides extend between first and second partially reflecting end facets. The first waveguide terminates at the first facet with a high reflection coating and at the second facet with an anti-reflection coating. The second waveguide terminates at the first facet with an anti-reflection coating and at the second facet with a high reflection coating. Thus, the feedback path for the laser involves portions of both waveguides and the coupling region therebetween. As a result, no standing waves are set up in either waveguide near the portions of the end facets which are anti-reflection coated and from which radiation is emitted so that processes which cause emitting facets to fail at high powers are mitigated.

Abstract: The present invention is a semiconductor diode laser array which favors oscillation in the zero degree phase shift mode. The array comprises first and second sets of waveguides which are interdigitated in a coupling region. Energy transfer between the first and second sets of waveguides by way of evanescent coupling is needed to define the feedback paths for sustaining laser oscillations in the waveguides. Such coupling is optimum and the threshold current for lasing lowest when all of the waveguides in both sets oscillate in phase.