Patents by Inventor William Streifer

William Streifer has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5219785
    Abstract: A method using implantation to form a semiconductor laser or laser array with current blocking implants. A semiconductor material laser structure including layers of a first conductivity type, an active region and layers of a second conductivity type is formed. In a first embodiment, impurity ions of the second conductivity type are implanted into selected regions of a first conductivity type layer. The implanted ions form current blocking buried regions of the second conductivity type with current confining channels therebetween. Finally, the structure is thermally annealed. In a second embodiment, a disorder inducing impurity, which may be a saturable absorber, is diffused into selected portions of the layers of the first conductivity type through the active region. The diffusion converts side regions of those layers into the second conductivity type.
    Type: Grant
    Filed: July 25, 1990
    Date of Patent: June 15, 1993
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: David F. Welch, Donald R. Scifres, William Streifer
  • Patent number: 5193098
    Abstract: A method using implantation to form a semiconductor laser or laser array with current blocking implants. A semiconductor material laser structure including layers of a first conductivity type, an active region and layers of a second conductivity type is formed. In a first embodiment, impurity ions of the second conductivity type are implanted into selected regions of a first conductivity type layer. The implanted ions form current blocking buried regions of the second conductivity type with current confining channels therebetween. Finally, the structure is thermally annealed. In a second embodiment, a disorder inducing impurity, which may be a saturable absorber, is diffused into selected portions of the layers of the first conductivity type through the active region. The diffusion converts side regions of those layers into the second conductivity type.
    Type: Grant
    Filed: August 24, 1992
    Date of Patent: March 9, 1993
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: David F. Welch, Donald R. Scifres, William Streifer
  • Patent number: 5103456
    Abstract: An integrated master oscillator/power amplifier semiconduction device having a laser diode oscillator, a broad area light amplifier and a coupling grating disposed to deflect light at an angle from the laser oscillator to the light amplifier. The amplifier may terminate as an output facet or use a grating surface emitter to couple amplified light out of the device. The orientation angle and grating period of the coupling grating are chosen to minimize feedback from the amplifier into the laser. This is achieved either by deflecting the light by other than a 90.degree. angle or by orienting the grating at other than 45.degree. with respect to laser even though light is deflected by 90.degree. so that any return light effectively "sees" a different grating. The laser can be a DFB or DBR laser and can be wavelength tunable.
    Type: Grant
    Filed: July 30, 1990
    Date of Patent: April 7, 1992
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Donald R. Scifres, David F. Welch, William Streifer, deceased
  • Patent number: 5088105
    Abstract: An optical amplifier having one or more amplifier regions with a noncollinear light path provided by curved or folded waveguides therein between input, output and reflective surfaces provided, for example, by a low reflectivity front facet and a high reflectivity rear facet. The amplifier regions are electrically pumped via conductive contacts which may be individually addressable for each amplifier region to provide phase control of the array of emitted light. Light is accepted through the front facet by a first amplifier region, is reflected from the rear facet and is emitted through the front facet. If there are multiple amplifier regions, a portion of the light is reflected by the front facet into an adjacent amplifier region. The light path is incident on the front and rear facets at an angle other than normal thereto and preferably at most 10.degree. from normal.
    Type: Grant
    Filed: March 26, 1991
    Date of Patent: February 11, 1992
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Donald R. Scifres, David F. Welch, William Streifer, deceased
  • Patent number: 5048036
    Abstract: Semiconductor heterostructure lasers having at least one lattice mismatched strain layer in the cladding proximate to the active region. Indium or phosphorus may be added in high concentration to form the strain layers. The strain layers may be spaced somewhat apart from the active region or may be adjacent to the active region. In either case, the strain layers decrease transparency current and increase differential gain.
    Type: Grant
    Filed: January 4, 1991
    Date of Patent: September 10, 1991
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Donald R. Scifres, David F. Welch, John Endriz, William Streifer, deceased
  • Patent number: 4995050
    Abstract: A diode laser external lens cavity configuration having a stripe mirror with two thin parallel stripes placed in front of the two lobes of the arrays for far field output pattern. The configuration includes a diode laser array or broad area laser, a lens system, such as a graded-index lens, disposed in front of the laser's front light emitting facet and the stripe mirror disposed in front of the lens system at the focal plane of the lens. The two stripes are parallel to one another on opposite sides of and equidistant from a vertical reference plane through the lens' center axis. One stripe is highly reflective, while the other is effectively only partially reflective having either a lower stripe reflectivity or shorter length than the first stripe. Other embodiments include a third stripe spaced from and collinear with the second stripe to form an etalon, and a grating in the cavity.
    Type: Grant
    Filed: November 17, 1989
    Date of Patent: February 19, 1991
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Robert G. Waarts, William Streifer, Donald R. Scifres
  • Patent number: 4984242
    Abstract: GaAs/AlGaAs heterostructure lasers containing indium in at least one layer other than or in addition to the active region. Embodiments are described in which indium added in low concentration to the cladding functions to match the lattice constants between the cladding and active layers, in which indium is added in high concentration to form strain layers that prevent defect migration therethrough and if proximate to the active region decrease transparency current and increase differential gain, in which indium is added uniformly to all layers to suppress defect formation, and in which indium is added to a cap layer to reduce metallization contact resistance.
    Type: Grant
    Filed: September 18, 1989
    Date of Patent: January 8, 1991
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Donald R. Scifres, David F. Welch, John Endriz, William Streifer
  • Patent number: 4972427
    Abstract: A diode laser of the type having an array of laser emitters in a Talbot cavity in which edge reflectors are added to enhance feedback to edgemost emitters. In one embodiment, a transparent slab with reflectively coated sides is present between the phase plane of the emitted light and the Talbot cavity reflector. The phase plne is defined by a lenticular array placed a focal length in front of the laser emitters. In another embodiment, the Talbot cavity reflector has an increased reflectivity toward its edges. In all embodiments the Talbot cavity reflector is preferably spaced a distance na.sup.2 /.lambda. from the phase plane, where n is a positive integer, a is separation between adjacent emitters and .lambda. is the wavelength of emitted light. An integrated embodiment has the array and cavity reflectors defined ina single semiconductor body divided into active and ransparent region. Side mirrors are etched into the semiconductor body.
    Type: Grant
    Filed: September 14, 1989
    Date of Patent: November 20, 1990
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: William Streifer, Robert G. Waarts, David F. Welch, Donald R. Scifres
  • Patent number: 4933301
    Abstract: 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.
    Type: Grant
    Filed: January 27, 1989
    Date of Patent: June 12, 1990
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Donald R. Scifres, David Welch, Peter Cross, William Streifer
  • Patent number: 4862802
    Abstract: A pyrotechnic ignition method in which a semiconductor laser bar or bars containing a number of independent laser array sources deliver optical power in a specified sequence through optical fibers to a set of pyrotechnic elements in order to initiate a sequence of pyrotechnic events, such as a fireworks display, building demolition, emergency ejection sequence, satellite launch, etc. A command signal is transmitted and received, typically by a remote station from the user. The signal is decoded to generate a set of electrical signals representing addresses of individual laser arrays on the laser bar. The laser arrays are activated in the desired sequence in response to the set of electrical signals and emit laser light. This light is transmitted along optical fibers coupled to the individual laser arrays and terminating in pyrotechnic elements. The pyrotechnic elements are ignited in response to optical power received from the optical fibers, typically by direct heating of a detonator.
    Type: Grant
    Filed: July 11, 1988
    Date of Patent: September 5, 1989
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: William Streifer, Donald R. Scifres, Jerome R. Klein
  • Patent number: 4831630
    Abstract: A laser in which the central portion is provided with current pumping means consisting of an array of current confining stripe contacts to provide a multiple emitter active layer and the end sections of the laser are provided with transparent waveguides. The active layer of this laser can be abruptly stepped along the direction of light propagation, or provided with tapered end couplers, or in any other way made transparent, so that light escapes from the emitters of the active layer of the central portion of the laser into the transparent waveguides at the ends of the laser. The transparent waveguides are of a non-absorbing material of higher bandgap than the central active layer material, or of the same material but otherwise rendered transparent, so that the escaping light strikes the mirror facets and is reflected back, whereby a portion of the reflected light couples back into its emitter and provides the optical feedback for laser operation.
    Type: Grant
    Filed: November 20, 1987
    Date of Patent: May 16, 1989
    Assignee: Xerox Corporation
    Inventors: Donald R. Scifres, William Streifer, Robert D. Burnham
  • Patent number: 4826269
    Abstract: A plurality of diode lasers is focussed onto a single region by arranging the diodes at equally spaced locations on a first arc. Each diode laser emits light in a slit-like pattern which is characterized by orthogonal axes. In a first group of cylindrical lenses, one associated with each diode laser, each lens has a refractive surface having an axis parallel to one of the emitting axes of the laser and refracts light to a focal region of defined dimensions. Each cylindrical lens is disposed along a second arc having a circular center common with the first arc. A second group of cylindrical lenses, one associated with each laser, is also disposed on a circular arc, concentric with the other arcs, but the second group has a refractive axis perpendicular to the first refractive axis. The second group of cylindrical lenses acts upon the second axis of the source image, focussing it to the common focal region. The first and second cylindrical lens groups may be combined into a toric surface within a single lens.
    Type: Grant
    Filed: October 16, 1987
    Date of Patent: May 2, 1989
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: William Streifer, Donald R. Scifres, Gary L. Harnagel
  • Patent number: 4815084
    Abstract: Lasers and laser arrays having various optical elements, such as lenses, apertures, prisms, etalons and phase plates, integrated within the resonant optical cavity of the laser. The optical elements are created by introducing a lateral geometric contour in boundaries of refractive index changes thereby causing a change in shape of phase fronts of lightwaves propagating in the laser cavity in a manner analogous to optical elements. Boundaries may be defined between an active region and transparent window regions or may be formed in other layers with which lightwaves interact, such as the layers bounding the active region. Curved boundaries produce convergent or divergent lenses. Absorbing regions may bound window regions to produce apertures for lateral mode control. A periodic step shaped boundary can be used to shift the phase of lightwaves propagating in some laser array waveguides relative to lightwaves in others of the waveguides in order to cause beam emission of a desired supermode.
    Type: Grant
    Filed: May 20, 1987
    Date of Patent: March 21, 1989
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Donald R. Scifres, William Streifer
  • Patent number: 4809288
    Abstract: 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.
    Type: Grant
    Filed: March 4, 1987
    Date of Patent: February 28, 1989
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: David Welch, Donald R. Scifres, Peter Cross, William Streifer
  • Patent number: 4803691
    Abstract: 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.
    Type: Grant
    Filed: August 28, 1987
    Date of Patent: February 7, 1989
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Donald R. Scifres, Hsing Kung, Peter Cross, Robert D. Burnham, William Streifer
  • Patent number: 4799223
    Abstract: A split contact phased array laser comprising a plurality of parallel emitters under phase locked operation and productive of an output beam having a preferred emission wavelength and preferred far field mode of operation. The charge distribution profile in the laser is changed to cause the output beam to deflect and scan in the far field. The improvement in the laser is the provision of at least three independently current pumped segments formed transversely of said emitters wherein at least one of the segments is current pumped above threshold level sufficient to primarily determine the emission wavelength and mode of operation of the laser while the current supplied to the remaining segments is below this level and is varied relative to one another to cause the output beam to deflect and scan in the far field without substantial change to the emission wavelength and mode of operation.
    Type: Grant
    Filed: August 6, 1987
    Date of Patent: January 17, 1989
    Assignee: Xerox Corporation
    Inventors: William Streifer, Robert D. Burnham, Thomas L. Paoli
  • Patent number: 4719630
    Abstract: A phased array semiconductor laser favoring emission in the 1st or Nth supermode over other potential supermodes of the laser comprising a plurality of spatially disposed laser elements formed relative to an active region to provide optical cavities for light wave generation and propagation under lasing conditions and wherein the optical field of laser elements are coupled into the optical cavities of adjacent laser elements to provide a phase locked condition across the array. The position of the outer laser element at each end of the array are spaced closer to adjacent laser element compared to the spacing provided between all the other of laser elements such that the coupling across the array is enhanced to produce at least one supermode with a nearly uniform and fairly rectangular shaped intensity envelope. The optimized optical coupling coefficient between the outer lasing elements and their adjacent laser elements is .sqroot.
    Type: Grant
    Filed: March 24, 1986
    Date of Patent: January 12, 1988
    Assignee: Xerox Corporation
    Inventor: William Streifer
  • Patent number: 4719634
    Abstract: 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.
    Type: Grant
    Filed: October 27, 1986
    Date of Patent: January 12, 1988
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: William Streifer, Peter Cross, Donald R. Scifres
  • Patent number: 4718069
    Abstract: A semiconductor laser array having a single lobe far field intensity pattern radiating normal to the laser's light emitting facet. The laser array has a plurality of semiconductor layers disposed over a substrate, at least one of the layers forming an active region for lightwave generation and propagation under lasing conditions. A plurality of adjacent spaced apart optical waveguides defined by waveguides and interconnecting waveguides directly couples lightwaves propagating in each waveguide into an adjacent waveguide. The waveguides are characterized by separations which are not equal at the light emitting facet but are selectively varied so that the sampling function has only a single central lobe. In the preferred embodiment, separations are greatest for edge located and smallest for centrally located waveguides. Interconnecting waveguides connect adjacent waveguides at respective Y-shaped junctions, the junctions being symmetric at least on the output side of the laser.
    Type: Grant
    Filed: October 27, 1986
    Date of Patent: January 5, 1988
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: William Streifer, Donald R. Scifres
  • Patent number: 4694459
    Abstract: A hybrid index/gain guided semiconductor laser has a gain guide type body with index waveguide attributes is characterized by having two regions of current confinement means. The first of these regions contains primary current confinement means and at least one second region which includes a pair of current confinement means parallel to each other and axially offset relative to the axis of the primary current confinement means and extend from the other laser facet toward the first region. The axially offset current confinement means in the second region provide regions of lower refractive index in the laser structure compared to the region of the laser optical cavity established between the offset current confinement means and, as a result, function as an index optical waveguide for the laser. The first region may be electrically isolated from the second region so that the first region is independently pumped relative to the second region.
    Type: Grant
    Filed: May 31, 1985
    Date of Patent: September 15, 1987
    Assignee: Xerox Corporation
    Inventors: Robert D. Burnham, Thomas L. Paoli, Donald R. Scifres, William Streifer