Spectra Diode Laboratories, Inc.

Peter Cross

Donald R Scifres

William Streifer

David F Welch

Robert D Burnham

Gary L Harnagel

Hsing Kung

A method of making semiconductor laser arrays having an impurity disordered pattern of waveguides at least some of which are directly joined at branching junctions. The region near the branching junctions provides a phase boundary condition in which lightwaves propagating in adjacent waveguides are in phase. Using one impurity dose and one disordering depth in a first portion of the pattern and another in a second portion of the pattern provides a combination of strong and weak waveguiding with strong waveguides that eliminate evanescent coupling from occurring at least in the branching junction regions, and with weak guides near one or both end facets permitting evanescent coupling. The evanescent coupling between adjacent weak waveguides preserves the in phase relationship that was established in the Y-junction regions, resulting in a diffraction limited single lobe far field output. Alternatively, even without evanescent coupling, the modes can adjust their phases in the weak waveguides, where the propagation constant is less tightly specified by the geometry.

Method of forming a semiconductor laser

A semiconductor laser array having a plurality of waveguides at least some of which are directly joined at Y-junctions. The region near the Y-junctions provides a phase boundary condition in which lightwaves propagating in adjacent waveguides are in phase. A combination of strong and weak waveguiding is provided, with strong waveguides that eliminate evanescent coupling from occuring at least in the Y-junction regions, and with weak guides near one or both end facets permitting evanescent coupling. The evanescent coupling between adjacent weak waveguides preserves the in phase relationship that was established in the Y-junction regions, resulting in a diffraction limited single lobe far field output. Alternatively, even without evanescent coupling, the modes can adjust their phases in the weak waveguides, where the propagation constant is less tightly specified by the geometry.

Hybrid Y-junction laser array

A diode laser bar producing a linear array of laser beams without lateral superradiance. The laser bar has a double-heterostructure or quantum well structure. Etched channels in the substrate create lateral corrugations in the subsequently deposited layers including the active region. The corrugations alternate between offset groove and plateau regions in the lateral direction but are straight in the longitudinal light propagating direction. Any laterally propagating light is interrupted at steps, between groove and plateau regions, by deflection, scattering or transmission out of the active region. Interruption may also be achieved with a plurality of parallel etched grooves extending in the longitudinal direction. The grooves which cut through the active region present a semiconductor-air interface for reflection and/or scattering of laterally propagating light out of the active region. Proton bombarded regions may be provided above the step regions in the top layers to channel current and prevent optical burnout of the step regions. A small percentage of laser light may be allowed to laterally propagate into adjacent active regions to promote phase locking across the laser bar.

Lateral superradiance suppressing diode laser bar

A phased array laser having a laterally asymmetric variation in the gain or coupling of lasing elements of the array for emission in a single far field lobe. The lasing elements are confined by internal waveguide structuring, periodically spaced current confinement stripes, or by a hybrid of both waveguiding and current confinement. The widths, lengths, depths, or separations of the waveguides or stripes vary laterally across the array to affect the gain or coupling of the lasing elements. Alternate embodiments introduce lateral asymmetry in the active region or other layer thicknesses, doping, mirror facet reflectivities, A1 content of the layers, heat dissipation, or thicknesses of electrical contacts. The laterally asymmetric variations may be linear or nonlinear, monotonically increase from one edge to the other edge, or may be such that the relevant parameter is greatest or least in the center of the array.

Asymmetric offset stripe laser for emission in a single lobe

A semiconductor laser array having a plurality of sets of interconnecting waveguides, each joining two optical waveguides together at respective branching junctions. The array has a plurality of semiconductor layers disposed on a substrate, at least one of the layers forming an active region for light wave generation and propagation under lasing conditions. One or more structures, such as current confining channels, a channelled substrate and variable thickness active region define a plurality of adjacent optical emitting waveguides. The waveguides are coupled together in a coupling geometry which ensures that breaks or failures in one or more branches are bypassed, thereby maintaining in-phase laser array operation.

Semiconductor laser array with fault tolerant coupling

A diode laser array assembly made from a plurality of linear diode laser array subassemblies stacked one above the other. Each subassembly is an array of individual laser beam emitters, such as a laser bar, mounted on a support plate. An electrically conductive path goes from one major surface of a support plate, through the linear laser array, to an opposite major surface of the support plate. Each subassembly is connected physically and electrically to adjacent subassemblies to form the final assembly. In one embodiment, the support plates are electrically insulating and partly coated or covered with conducting material. The plates are either rectangular with projections and directly connected, rectangular with metal plates between each other, or rectangular and connected in a staircase configuration. Alternatively, the support plates may be electrically conducting with an insulating layer and a conducting layer disposed in a sandwich configuration. The plates may also be made up of an electrically insulating support plate and an electrically conducting spacer plate.

Growing community of inventors

Palo Alto, CA, United States of America

Peter Cross