Abstract: A wafer that is cleaved to provide a facet for a Fabry-Perot cavity is provided with Bragg gratings whose axes are offset by a small angle from the axis of the Fabry Perot cavity to offset the effect of the randomly uncontrollable location of the cleaved facet on the optical phase of the grating feedback.

Abstract: A wafer that is cleaved to provide a facet for a Fabry-Perot cavity is provided with Bragg gratings whose axes are offset by a small angle from the axis of the Fabry Perot cavity to offset the effect of the randomly uncontrollable location of the cleaved facet on the optical phase of the grating feedback.

Abstract: In order to provide an improved heat transfer interface between an solid state device and a heat sink to which it is soldered, one or more “vents” are provided in the interface between the solid state device and the heat sink to prevent the entrapment of gases that could form solder voids. Advantageously, the provision of such vents in the interface surface geometry of the semiconductor may be effected by the use of appropriate masking and etching following the epitaxial regrowth process. Alternatively, the heat sink or a solder preform may be provided with suitable notches. The use of such “die-bond vents” also allows solder, after melting, to be forced under the chip by external gas pressure such that no solder voids are left.

Abstract: In order to provide an improved heat transfer interface between an solid state device and a heat sink to which it is soldered, one or more “vents” are provided in the interface between the solid state device and the heat sink to prevent the entrapment of gases that could form solder voids. Advantageously, the provision of such vents in the interface surface geometry of the semiconductor may be effected by the use of appropriate masking and etching following the epitaxial regrowth process. Alternatively, the heat sink or a solder preform may be provided with suitable notches. The use of such “die-bond vents” also allows solder, after melting, to be forced under the chip by external gas pressure such that no solder voids are left.

Abstract: A surface-emitting distributed feedback (SEDFB) laser is provided with a “fan-shaped” grating comprising a group of generally straight lines radiating from a central point that is away from the center of the gain. Such a grating provides better stability against self-induced filamentation and dynamic instabilities that limit achievable beam quality, especially in lasers having a stripe length greater than 1 mm.

Abstract: A surface-emitting distributed feedback (SEDFB) laser is provided with a “fan-shaped” grating comprising a group of generally straight lines radiating from a central point that is away from the center of the gain. Such a grating provides better stability against self-induced filamentation and dynamic instabilities that limit achievable beam quality, especially in lasers having a stripe length greater than 1 mm.

Abstract: A wafer supporting a semiconductor structure having a material gain function that would preferentially support an F-P laser mode at an unwanted wavelength &lgr;2 is provided with a second order dielectric grating located sufficiently remotely from the high intensity optical field of the quantum well and the waveguide to receive just enough transverse mode energy to provide feedback to reduce the gain at &lgr;2 and support oscillation at a desired wavelength &lgr;1. More particularly, by providing a gain discrimination factor &agr;≈0.1 cm−1, the fraction of power lost to transverse mode radiation can be held to about 1% which is sufficient to provide stabilizing feedback without sapping too much energy from the longitudinal beam.