Patents Assigned to Spectra Diode Laboratories, Inc.
  • Patent number: 5231642
    Abstract: A semiconductor laser that includes at least one grating reflector with a grating period selected to diffract at a nonperpendicular angle within the plane of the laser waveguide. This allows dispersal of laser light, eliminating filamentary multimode operation of broad area lasers. In one embodiment, the grating reflector couples light between a single transverse mode waveguide portion of the optical cavity and a second, broad area, portion that is not collinear with the single mode waveguide. In another embodiment, the cavity favors a ring mode of oscillation. One or more grating reflectors form part of the feedback mechanism which forms a resonant optical cavity with noncollinear portions. Other reflectors in the feedback mechanism include facet reflectors which can be cleaved or ion milled, or semiconductor material refractive index boundaries. Laser embodiments with two or more grating reflectors can be independently tuned to provide a high rate of amplitude modulation.
    Type: Grant
    Filed: May 8, 1992
    Date of Patent: July 27, 1993
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Donald R. Scifres, Kenneth M. Dzurko, Robert G. Waarts, David F. Welch, Amos Hardy, Stephen O'Brien
  • 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: 5185754
    Abstract: A laser diode construction having internal reflectors within the laser cavity to provide a stable spectral mode of laser operation. The laser includes a plurality of contiguous semiconductor layers disposed on a substrate to form a semiconductor body with at least one layer forming an active region. Electrically conductive contacts bias the heterostructure to inject current into the active region and produce lightwaves. Feedback means define two or more tandem resonant optical cavities to achieve lasing operation. The feedback means includes at least one internal light reflector within the semiconductor body. In a preferred embodiment, a pair of spaced apart internal reflectors are provided with the region between the pair also being electrically pumped to define an active internal etalon. Other embodiments have multiple periodic reflectors or combine internal reflectors with feedback gratings or passive windows at the end facets of the body.
    Type: Grant
    Filed: July 29, 1991
    Date of Patent: February 9, 1993
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Richard R. Craig, David F. Welch, Erik P. Zucker, Donald R. Scifres, William J. Gignac
  • Patent number: 5185752
    Abstract: Arrangements for efficiently coupling light between a laser diode and a second-harmonic generator which feature external resonant cavities that include a feedback grating fabricated on the second-harmonic generator. The feedback grating reflects light of a first frequency that matches the frequency doubling band of the second-harmonic generator, thereby establishing stable laser oscillation at that first frequency. Preferably, the second-harmonic generator has a periodically-poled waveguide formed in the surface of the nonlinear material body. The laser diode may be butted against the harmonic generator or coupling optics may be positioned between the two. In one arrangement, a polarizer is placed in the resonant cavity, either between an external back reflector and the back facet of the laser diode or between the antireflection coated front facet of the laser diode and the harmonic generator, to provide loss to the TE polarization mode and enhance oscillation in the TM polarization mode.
    Type: Grant
    Filed: February 18, 1992
    Date of Patent: February 9, 1993
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: David F. Welch, Robert G. Waarts
  • Patent number: 5168401
    Abstract: An optical system for use in conjunction with a one or two dimensional array of high brightness sources where such sources are individually rotated by multiple reflective elements and in turn may be captured by beam filling optics and subsequently re-imaged by symmetric and asymmetric optics where the asymmetric optics preferentially image a single dimension while leaving the focus in the second dimension largely unaffected. In this manner and by properly selecting the spacing as well as the width of the line sources, and by properly designing the symmetric and asymmetric optics, the array of high brightness sources can be reformatted in a brightness conserving manner that allows the reformatted beam to simultaneously have an arbitrary ratio of image length to image width and arbitrary divergences in the respective dimensions.
    Type: Grant
    Filed: May 7, 1991
    Date of Patent: December 1, 1992
    Assignee: Spectra Diode Laboratories, Inc.
    Inventor: John Endriz
  • Patent number: 5159604
    Abstract: In a semiconductor laser array structure in which antiguided regions between high effective refractive index waveguide regions experience greater gain then the waveguide regions, structures introduced at the sides of the array, next to the edgemost waveguides and not on the array period, reflect laterally transmitted radiation back toward the center of the array. The edge reflecting structures may be waveguide regions having widths of (m'+1/2) half-wavelengths, where "m'" is zero or a positive integer, compared to array waveguides with width m, where "m" is an integer not necessarily equal to "m'". The edge reflecting structures may also be stacks of such waveguides, where the regions between the edge waveguides are of a width substantially equal to (n'+1/2) half-wavelengths, compared to antiguide element widths of n half-wavelengths. The two integers n and n' may be, but are not necessarily, equal.
    Type: Grant
    Filed: July 29, 1991
    Date of Patent: October 27, 1992
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: David G. Mehuys, Amos A. Hardy, David F. Welch, Robert G. Waarts, Donald R. Scifres
  • 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: 5099488
    Abstract: A laser array submount structure for assembly into a two-dimensional stacked array with precise separation between laser diodes of adjacent submounts. The submount includes a deformable metal layer, such as a soft solder, on one major surface of a laser array support plate. A spacer element having spaced apart ridges is disposed on the opposite major surface. A laser diode array is mounted on a front edge of the support plate. In a cold bonding step, submounts are pressed together causing ridges to penetrate the deformable metal layer to a specified depth. The displaced metal spreads into channels between the ridges, allowing pressing of multiple laser array submounts into stackes of precise total tolerance.
    Type: Grant
    Filed: March 27, 1991
    Date of Patent: March 24, 1992
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Mitra Ahrabi, Gerald S. Browder, John G. Endriz, Gary L. Harnagel, D. Philip Worland
  • 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: 5065401
    Abstract: A method of driving a multimode laser diode has pulse circuitry providing a sequence of drive current pulses to the laser and modulation circuitry superimposing a modulation current upon the drive current pulses. When the modulation amplitude and rate are sufficiently great, rapid switching of transverse modes of laser operation is induced during each laser pulse. The effect of many different modes is averaged out so that the observed light output, even in a high power apertured system, is stable both within a single pulse and from one pulse to the next.
    Type: Grant
    Filed: February 26, 1991
    Date of Patent: November 12, 1991
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Donald R. Scifres, John G. Endriz
  • 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: 5033054
    Abstract: A laser having a phase conjugating reflector positioned with a resonant cavity of a laser configuration capable of multimode operation. The resonant cavity or other means associated with the laser configuration selects the preferred mode at threshold. The phase conjugating material builds up reflectivity as the light intensity is increased above threshold power levels to maintain the selected mode to high power levels. One embodiment has an external Talbot cavity with a first mirror in a Talbot plane of a multi-emitter laser array and with the phase conjugating material at a sub-Talbot plane. Another embodiment has an external GRIN lens cavity with a far field apertured stripe mirror for threshold mode selection. The phase conjugator is placed at a high light intensity position within the cavity such as adjacent to the stripe mirror or adjacent to the laser array. The laser source may be a linear laser diode array or a 2-D surface emitting laser array.
    Type: Grant
    Filed: August 17, 1990
    Date of Patent: July 16, 1991
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Donald R. Scifres, Richard R. Craig, Robert G. Waarts
  • Patent number: 5003550
    Abstract: A monolithic integrated master oscillator power amplifier (MOPA) device including a single mode diode laser with distributed Bragg reflectors, an amplifier in tandem with the laser, lateral phase controllers and a detuned second order grating surface output coupler, all on a common substrate. The amplifier is a flared waveguide in one embodiment, and a branching network of single mode waveguides followed by an array of single mode gain waveguides in another embodiment. The diode laser is tunable by means of a separate tuning current applied to the rear Bragg reflector. Tuning the laser wavelength provides, in conjunction with the output coupler, a longitudinal steering of the output beam. The lateral phase controllers are an array of separately addressable electrodes that adjust the optical path length to compensate for phase variation in the amplifiers and also to provide lateral steering of the output beam.
    Type: Grant
    Filed: March 9, 1990
    Date of Patent: March 26, 1991
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: David F. Welch, Robert G. Waarts, David G. Mehuys, Richard R. Craig
  • 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: 4934273
    Abstract: A compact laser flare illuminator includes a semiconductor diode laser array radiation source, an energy source for the radiation source that can be switched on and a housing which holds the array and energy source, while allowing egress of a beam. This illuminator may be used to facilitate night vision by persons wearing night vision goggles or using other types of wavelength-selective night vision devices. The housing may serve as a heat sink and may be equipped with a propulsion device and with fins for flight stabilization, as well as with a parachute for slowing descent from an altitude above an area to be illuminated. A wavelength filter that passes radiation only in a predetermined wavelength range and a lens or optical element to focus the laser radiation toward the area to be illuminated are optional features.
    Type: Grant
    Filed: June 20, 1989
    Date of Patent: June 19, 1990
    Assignee: Spectra Diode Laboratories, Inc.
    Inventor: John G. Endriz
  • 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: RE33722
    Abstract: An optical system producing bright light output for optical pumping, communications, illumination and the like in which one or more fiberoptic waveguides receive light from one or more diode lasers or diode laser bars and transmit the light to an output end where it is focused or collimated into a bright light image. The input end of the fiberoptic waveguide may be squashed into an elongated cross section so as to guide light emitted from an elongated light source such as a diode laser bar. The waveguides are preferably arranged at the output end into a tightly packed bundle where a lens or other optical means focuses or collimates the light. For diode laser bars much wider than 100 microns, a plurality of waveguides may be arranged in a line to receive the light, and then stacked at the output in a less elongated configuration. In this manner, light from many diode lasers or laser bars may be coupled through the bundle into the end of solid state laser medium.
    Type: Grant
    Filed: August 15, 1990
    Date of Patent: October 22, 1991
    Assignee: Spectra Diode Laboratories, Inc.
    Inventors: Donald R. Scifres, D. Philip Worland