Patents Assigned to SDL, Inc.
  • Patent number: 6044096
    Abstract: A system and method for operating a high power laser diode device with high efficiency coupling of a laser diode bar. The laser diode bar and a micro-cylinder lens are vertically oriented in a device package, such that the array axis of the laser bar and the longitudinal axis of the micro-cylinder lens are aligned substantially parallel to a gravity vector. In the two different embodiments disclosed, either initial collimation of the fast-axis divergence or, alternatively, initial collimation of both the fast-axis and slow-axis divergences take place before beam reformatting via a beam array turning mirror. Additionally, the vertical orientation of these components is combined with methods of compensating for the bending or "smile" of the laser diode bar to provide for optimal output beam coupling, resulting in a uniform far field intensity distribution.
    Type: Grant
    Filed: November 3, 1997
    Date of Patent: March 28, 2000
    Assignee: SDL, Inc.
    Inventors: Edmund L. Wolak, John G. Endriz
  • Patent number: 6041072
    Abstract: Apparatus for stabilizing multiple laser sources having distinguishable optical characteristics, e.g., in polarization field or operational wavelength, comprises a plurality of semiconductor laser sources having respective lasing cavities capable of lasing within a narrow bandwidth of wavelengths and providing spectral outputs at their respective laser exit facets having different optical characteristics from one another. The spectral output beams of the sources may be coupled to respective optical fibers and the beams combined via a beam combiner, e.g., a polarizing beam combiner or a WDM combiner. The beam combiner combines the beam outputs forming a single beam which is launched into an output optical fiber. At least one feedback fiber grating is provided in at least one of the optical fibers with the number thereof depending upon distinguishable optical characteristics of the multiple laser sources.
    Type: Grant
    Filed: May 19, 1998
    Date of Patent: March 21, 2000
    Assignee: SDL, Inc.
    Inventors: Brian F. Ventrudo, Peter G. Berrang
  • Patent number: 6041070
    Abstract: A fiber laser or fiber amplifier uses resonant pumping of the gain medium by providing a pump resonator that establishes a resonator cavity at the pump wavelength which includes the pumped gain medium. The pump resonator may be of a distributed feedback (DFB) or a distributed Bragg reflector (DBR) type construction, and may be combined with signal reflection apparatus of either DFB or DBR type construction that provides oscillation of the desired laser output wavelength. If used without a signal reflection apparatus, the invention may be operated as a resonant pumped fiber amplifier. Resonant pumped lasers may be arranged in series to provide a laser apparatus with a selectable output wavelength. The different laser stages each provide resonance for a different pump wavelength, and each provide resonance for a different signal wavelength.
    Type: Grant
    Filed: November 14, 1997
    Date of Patent: March 21, 2000
    Assignee: SDL, Inc.
    Inventors: Thomas L. Koch, Robert Waarts
  • Patent number: 6028722
    Abstract: A beam reconfiguring device comprises a single prism element that reconfigures a beam input, such as from a semiconductor laser or bar array, having aperture images with major axis aligned abreast along a single axis, into an output comprising multiple segments of the input image with a major axis of each segment aligned perpendicular along the same single axis. The etendue, the aperture-times-divergence product of a beam, in orthogonal directions of the output beam will be more nearly equal than the etendue in orthogonal directions of the input beam. The input beams and reconfigured beams are provided as adjacent inputs to a hypotenuse front edge surface of the prism element. The reconfigured beams are more conducive for converging into a single substantially symmetrical spot for input to an optical handling device or medium such as an optical fiber. An optical handling system is disclosed for achieving straight in-line, beam input/output that is more adaptable for optically aligned delivery applications.
    Type: Grant
    Filed: March 8, 1996
    Date of Patent: February 22, 2000
    Assignee: SDL, Inc.
    Inventor: Robert J. Lang
  • Patent number: 6025942
    Abstract: An infrared laser diode wireless local area network for communication between spatially dispersed terminals such as computers which may be located in a single room or in adjacent rooms. The lasers may be tuned to emit at varying frequencies for wavelength multiplexing, or a plurality of lasers each having a different output frequency can be connected with each terminal. A receiver connected to each terminal may similarly detect only a single narrow waveband or may detect a plurality of such wavebands. A transceiver may be employed for signal transmission between separate rooms. High speed data modulation of the carrier waves is provided with MOPA or similar lasers, and broad angular dispersion of the output is achieved by such lasers along with dispersive lenses.
    Type: Grant
    Filed: March 27, 1997
    Date of Patent: February 15, 2000
    Assignee: SDL, Inc.
    Inventor: Donald R. Scifres
  • Patent number: 6021141
    Abstract: A harmonic generator laser system which features a distributed Bragg reflector (DBR) or distributed feedback (DFB) tunable diode laser coupled to a quasi-phase matched (QPM) waveguide of optically nonlinear material. Tuning of the DBR laser may be achieved either thermally or via current injection, or both, halving the wavelength of a red laser into the visible blue spectral band. Thermal tuning may provide a coarse tuning adjustment, while injected current may provide fine tuning accessible to a user. Separately or in combination with current tuning, a modulation signal may be applied to the DBR laser for achieving an intensity modulated or a pulsed output. In another embodiment, modulation may be achieved by frequency modulation of the laser. A very compact tunable blue laser is formed. In yet another embodiment a double clad fiber amplifier is disposed between the tunable laser and the waveguide.
    Type: Grant
    Filed: February 28, 1997
    Date of Patent: February 1, 2000
    Assignee: SDL, Inc.
    Inventors: Derek W. Nam, David F. Welch, Robert G. Waarts, Jo S. Major
  • Patent number: 6014396
    Abstract: As to a first feature, a semiconductor optoelectronic device includes a resonator having an optical cavity between opposite end facets, a larger portion of a length of the resonator cavity comprising a single mode confining region for propagation of light and a smaller portion of a length of the resonator cavity comprising a tapered region for permitting propagation of light with a diverging phase front to a first of the end facets, which first facet is the light beam output. The tapered region provides a sufficiently large aperture to prevent catastrophic optical mirror damage (COD) at the first end facet while reducing the amount of required astigmatism correction while the single mode confining region provides spatial filtering to maintain diffraction-limited beam at the output. This structure therefore, more readily lends itself for incorporation into existing device packages designed for linear stripe laser diodes devices.
    Type: Grant
    Filed: September 5, 1997
    Date of Patent: January 11, 2000
    Assignee: SDL, Inc.
    Inventors: Julian S. Osinski, Robert J. Lang, Mats A. Hagberg
  • Patent number: 6008933
    Abstract: An optical amplifier makes use of a co-propagating fiber amplifier stage and a counter propagating fiber amplifier stage. One of the stages is preferably a low noise stage, while the other is a high gain stage, typically the output stage. The low noise stage may have a small core fiber while the high gain stage has a large core fiber. Pumping energy is introduced into the amplifier by coupling a plurality of laser sources in the same wavelength range using a narrow channel wavelength division multiplexer coupler. In each stage of the amplifier, some portion of the pump energy is transferred from the pumping wavelength to the signal wavelength. In a single polarization optical signal generator embodiment, the optical signal is developed in a distributed Bragg reflector oscillator having an output Bragg grating embedded in a polarization perserving fiber. A polarization controller is used at the amplifier output to restore the single polarization which is developed in the oscillator.
    Type: Grant
    Filed: August 19, 1997
    Date of Patent: December 28, 1999
    Assignee: SDL, Inc.
    Inventors: Stephen G. Grubb, Bernard G. Fidric
  • Patent number: 6007664
    Abstract: A method is disclosed for curing epoxy adhesive between the slider head and load/gimbal suspension assemblies of a disk drive access actuator employing a concentrated pulsed heat source rather than conventional, broadly applied heat source as employed in the past, such as oven heating or UV exposure. The laser source power is delivered via an optical fiber to the slider air-bearing surface (ABS) of the slider head assembly so that with this approach, the time for curing can be minimized and accurately controlled without causing damage to the assembly, and the overall curing step in the manufacturing process is reduced in time of application. Apparatus in the form of a fixture, such as an anvil element, provides a convenient gauge and support for alignment of the laser output beam with the slider ABS to which the heat for curing is to be applied as well as provide for its heat sinking.
    Type: Grant
    Filed: July 17, 1998
    Date of Patent: December 28, 1999
    Assignee: SDL, Inc.
    Inventors: Dirk J. Kuizenga, Richard H. Johnson
  • Patent number: 5991070
    Abstract: An optical amplifier uses a gain medium pumped with pump energy of a first wavelength that oscillates through the gain medium. In one embodiment, the pumping is essentially a cavity resonator that is coupled to either end of the gain medium such that oscillating pump energy passes through the gain medium as it reflects back and forth between the ends of the cavity. Highly reflective gratings may be used to maintain the oscillation of the pump energy, and a pump energy source, such as pumped doped optical fiber, is coupled to at least one of the gratings. In another embodiment, the pump source consists of multiple reflectors used at each end, and independent pump sources each having a slightly different wavelength within the absorption spectrum of the amplifier are coupled together, such that two pump wavelengths are simultaneously oscillated through the gain medium.
    Type: Grant
    Filed: November 14, 1997
    Date of Patent: November 23, 1999
    Assignee: SDL, Inc.
    Inventors: Raymond Zanoni, Robert Waarts
  • Patent number: 5966490
    Abstract: In a double-clad optical fiber comprising a core having an index of refraction n.sub.1, an inner cladding surrounding the core and having an index of refraction n.sub.2, and a first outer cladding surrounding the inner cladding and having an index of refraction n.sub.3 (wherein n.sub.1 >n.sub.2 >n.sub.3), the softness of the first outer cladding often renders it difficult to perform polishing or other mechanical operations on the end of the fiber. To reduce such difficulties it is advantageous to remove the first outer cladding from a limited end portion of the fiber, replacing it with a second outer cladding having an index of refraction n.sub.4 (wherein n.sub.2 >n.sub.4) and a hardness which is greater than that of the first outer cladding.
    Type: Grant
    Filed: March 21, 1997
    Date of Patent: October 12, 1999
    Assignee: SDL, Inc.
    Inventors: Richard A. Minns, Hong Po, William C. Robinson, Bennett H. Rockney, Ying Hua Zhang
  • Patent number: 5933705
    Abstract: A surface of a compound III-V semiconductor device is passivated and protected, respectively, by treatment with a sulfur-containing or selenium-containing passivation film on the surface followed by the deposit of a GaN, GaP, InGaP, GaAsP, ZnS or ZnSe protection layer. Prior to passivation and deposition of the protective layer, previously formed contact metalizations may be protected with a liftoff film or layer. A low temperature MOCVD process is used to deposit the protection layer so that the integrity of the previously deposited contact metalization is maintained. The preferred range for MOCVD deposition of the protection layer is in the range of about 300.degree. C. to about 450.degree. C. This processing temperature range is within a temperature range where stable contact metalization exists.
    Type: Grant
    Filed: September 12, 1997
    Date of Patent: August 3, 1999
    Assignee: SDL, Inc.
    Inventors: Randall S. Geels, Julian S. Osinski, David F. Welch, Donald R. Scifres
  • Patent number: 5933271
    Abstract: Two approaches are provided for achieving an optical amplifier system capable of producing high peak power, high energy pulse outputs while suppressing scattering noise. The first approach relates to an optical amplifier system which has at least one laser diode pulsed or cw pumped double clad fiber amplifier utilized for receiving a high frequency modulated injected signal pulse of short duration from the laser diode, via the fiber core, for amplification by coupling pump light into the inner cladding of the fiber. The average signal power is sufficient to saturate the gain of the fiber so as to minimize significant onset and buildup of forward and backward scattering noise. The duty cycle of the injected signal source pulse is chosen to allow adequate gain recovery in the fiber amplifier between pulses.
    Type: Grant
    Filed: February 2, 1998
    Date of Patent: August 3, 1999
    Assignee: SDL, Inc.
    Inventors: Robert G. Waarts, Steven Sanders, David F. Welch
  • Patent number: 5933265
    Abstract: An optical transmission link has both a transmitter module and a receiver module operable under uncooled conditions, i.e., without the need of costly cooling equipment, such as thermoelectric coolers. The optical transmission system includes both a semiconductor laser diode source and an optical receiver module that are both designed to operate uncooled under high frequencies (e.g., GHz range) over a wide temperature range without significant changes in signal bandwidth and at temperatures in excess of 125.degree. C. Compensation is provided to reduce the effect of photodiode noise and amplifier noise. In addition, temperature compensation can be provided that provides for overall reduction in receiver noise across the bandwidth of the receiver module through maintenance of a temperature environment optimizing receiver performance.
    Type: Grant
    Filed: April 22, 1998
    Date of Patent: August 3, 1999
    Assignee: SDL, Inc.
    Inventor: Radhakrishnan Nagarajan
  • Patent number: 5930030
    Abstract: An apparatus for pumping an optical gain medium, such as a fiber gain medium, comprises a pump source having a plurality of different spatially separate or multiple wavelengths or wavelength bands which are all coupled into the fiber gain medium and provide at least one or more wavelengths to fall within the absorption band of fiber gain medium producing gain despite wavelength shifts in the pump source multiple wavelengths due to changes in the operating temperature of the pump source. At least one or more of the pump wavelengths will overlap the gain spectrum of the fiber gain medium sufficiently to continually provide high input power for pumping of the fiber gain medium.
    Type: Grant
    Filed: July 30, 1998
    Date of Patent: July 27, 1999
    Assignee: SDL, Inc.
    Inventor: Donals R. Scifres
  • Patent number: 5930280
    Abstract: A laser system is provided for supplying high power, stable light intensity via an aperture limited delivery system to an application requiring continuous light output intensity in spite of the laser source being subjected optical feedback noise caused by external system and delivery system perturbations that cause fluctuation in laser source power intensity. Non-stable light intensity in the output is due to environmental temperature changes, and phase and amplitude changes caused by system induced perturbations such as by movement of the aperture limited delivery system and optical artifacts of the optical elements, comprising the aperture limited delivery system, introducing noise into the feedback in the laser system changing the output intensity pattern of the delivered power beam. This can be substantially remedied by the employing a monolithic, multiple, independent single mode laser source which is substantially unaffected by this noise.
    Type: Grant
    Filed: August 7, 1998
    Date of Patent: July 27, 1999
    Assignee: SDL, Inc.
    Inventors: David M. Rossi, Harrison L. Ransom, Jr.
  • Patent number: 5930029
    Abstract: An optical fiber amplifier having a doped fiber, through which an input signal propagates, is bi-directionally pumped in a manner that provides for a desired composite absorption profile such as, in one case, a uniform degree of local pump energy absorbed along at least a substantial length of the fiber. Co-propagating and a counter-propagating pump sources are prescribed to have their wavelengths selected relative to the peak absorption wavelength of the amplifier to provide for a uniform composite absorption profile across the length of the fiber thereby improving the overall inversion efficiency of the amplifier as well as providing for reduced amplifier noise figure.
    Type: Grant
    Filed: December 2, 1997
    Date of Patent: July 27, 1999
    Assignee: SDL, Inc.
    Inventor: David G. Mehuys
  • Patent number: 5926493
    Abstract: Optical semiconductor devices with integrated diffraction gratings with higher quality are realized through the use of Al-free grating layers. AlGaAs/GaAs regime optical semiconductor devices, such as laser diodes or optical filters, conventionally utilize an AlGaAs grating layer that has a strong affinity for oxidation. Instead of a Al-containing layer, a quantenary, InGaAsP grating layer is utilized, lattice matched to the underlying AlGaAs/GaAs structure, substantially eliminating any problem of oxide contamination. Also, an Al-free, ternary InGaP grating layer is utilized in the InGaP/InGaAsP/GaAs material regime. The quantum well active region of these devices may also be modified to extend the gain bandwidth of operation of these devices to insure continued operation over a wider temperature range with the wavelength peak of the grating in that the wavelength peak of the grating more assuredly remains within the wavelength operating range of the device.
    Type: Grant
    Filed: May 20, 1997
    Date of Patent: July 20, 1999
    Assignee: SDL, Inc.
    Inventors: Stephen O'Brien, Hanmin Zhao, Jo S. Major, Jr.
  • Patent number: 5926726
    Abstract: A method of manufacturing a p-type III-V nitride compound semiconductor utilizing vapor phase epitaxy is carried out in a MOCVD reactor by growing a III-V nitride compound semiconductor in the reactor employing a reaction gas containing a p-type impurity and then annealing in-situ the nitride compound semiconductor to bring about acceptor activation, the annealing carried out at a temperature below the growth temperature of the III-V nitride compound semiconductor during reactor cooldown. A nitrogen (N) reactant or precursor is provided in the reactor during the annealing step which can produce a reactive form of N capable of suppressing surface decomposition and does not produce atomic hydrogen. Also, acceptor activation is achieved through the employment of a cap layer comprising a n-type Group III-V nitride material, e.g., n-GaN, grown on the p-doped Group III-V nitride layer preventing the occurrence of hydrogenation of the underlying p-doped layer during cooldown.
    Type: Grant
    Filed: September 12, 1997
    Date of Patent: July 20, 1999
    Assignees: SDL, Inc., Xerox Corporation
    Inventors: David P. Bour, G.A. Neville Connell, Donald R. Scifres
  • Patent number: 5923692
    Abstract: A high-power two-dimensional edge-emitting diode laser array comprises mounting modules, laser bars mounted on the modules, and protective caps mounted on the bars opposite the modules. The lasers are electrically connected in series through the modules and caps. The caps serve as laser bar protectors during the bar burn-in. The caps have grooves which compensate for tolerances in the thicknesses of the lasers, modules, and caps. The array is mounted on a base plate, and is in thermal communication with a heat sink. The caps and/or modules are thermal-expansion-matched to the laser bars. Eliminating the need for a wire bond plate allows shortening the modules.
    Type: Grant
    Filed: October 24, 1996
    Date of Patent: July 13, 1999
    Assignee: SDL, Inc.
    Inventors: Michael P. Staskus, James M. Haden, John G. Endriz