Plural Cavities Patents (Class 372/97)
  • Publication number: 20030161361
    Abstract: A laser tuning mechanism which embodies “spectrally dependent spatial filtering” (SDSF) and contemplates two key elements of the tuning mechanism. The first element of the SDSF tuning mechanism is a spectrally dependent beam distortion (i.e. alteration of the amplitude and/or phase profile of the beam) provided by an SDSF tuning element in a laser cavity. The second element of the SDSF tuning mechanism is an intracavity spatial filter which makes the round trip cavity loss a sensitive function of both beam distortion and cavity alignment. Such a laser can be aligned so that a specific beam distortion, which is provided by the SDSF tuning element at a tunable wavelength, is required to obtain minimum round trip cavity loss, thereby providing tunable laser emission. A preferred embodiment of the SDSF tuning mechanism is an external cavity semiconductor laser having a zeroth order acousto-optic tuning element.
    Type: Application
    Filed: December 2, 2002
    Publication date: August 28, 2003
    Inventors: Barbara Paldus, Jinchun Xie, Robert Lodenkamper, David M. Adams, Eric Crosson, Alexander Katchanov, Grzegorz Pakulski, Chris W. Rella, Bruce A. Richman, Serguei Koulikov
  • Patent number: 6608846
    Abstract: A new class of bistable coupled-resonator vertical-cavity semiconductor laser devices has been developed. These bistable laser devices can be switched, either electrically or optically, between lasing and non-lasing states. A switching signal with a power of a fraction of a milliwatt can change the laser output of such a device by a factor of a hundred, thereby enabling a range of optical switching and data encoding applications.
    Type: Grant
    Filed: May 1, 2001
    Date of Patent: August 19, 2003
    Assignee: Sandia Corporation
    Inventors: Arthur J. Fischer, Kent D. Choquette, Weng W. Chow
  • Publication number: 20030147448
    Abstract: A semiconductor light emitting apparatus includes a semiconductor light emitting element which includes a stripe structure and an active layer made of an InGaN material, and emits first light without laser oscillation; an optical resonator; and a first wavelength selection unit which allows resonance, in the optical resonator, of second light having a selected wavelength included in the first light emitted by the semiconductor light emitting element. Alternatively, instead of the first wavelength selection unit, a second wavelength selection unit which allows output of only the above second light from the semiconductor light emitting apparatus may be provided. In this case, the semiconductor light emitting apparatus may further include an optical detector which detects intensity of the second light; and an output regularizing unit which drives the semiconductor light emitting element based on the detected intensity so as to regularize the intensity of the second light.
    Type: Application
    Filed: February 10, 2003
    Publication date: August 7, 2003
    Applicant: FUJI PHOTO FILM CO., LTD.
    Inventor: Toshiro Hayakawa
  • Publication number: 20030142708
    Abstract: A wavelength variable light source emits a light whose wavelengths continuously change from a preset start wavelength up to a stop wavelength to a measuring object. A timing information output section generates timing information showing emission timings of lights emitted from the wavelength variable light source and having start and stop wavelengths and a plurality of wavelengths obtained by delimiting the wavelengths between the start and stop wavelengths in predetermined steps. A light receiving section receives the light output from the measuring object and outputs a signal showing a measured value of a received light. A plurality of amplifiers receive the signal output from the light receiving section and amplify the signal at each predetermined amplification factor.
    Type: Application
    Filed: December 13, 2002
    Publication date: July 31, 2003
    Applicant: Anritsu Corporation
    Inventors: Takashi Sugimoto, Hiroaki Ohtateme
  • Patent number: 6600767
    Abstract: The present invention relates to a continuously tuneable free space laser. An amplifying medium in free space is placed inside a Fabry-Perot cavity consisting of two reflectors. One of these two mirrors being partially translucent and makes up the output mirror of the laser. According to the invention, the output mirror is inserted into the core of a monomode optic fiber that constitutes an output optic fiber and a lens placed in the Fabry-Perot cavity. This ensures coupling in this fiber of the luminous fluxes transmitted by the amplifying medium and the second reflector is self-aligned.
    Type: Grant
    Filed: July 23, 1999
    Date of Patent: July 29, 2003
    Assignee: Photonetics
    Inventor: Hervé Lefevre
  • Publication number: 20030138003
    Abstract: A laser system including a controller for monitoring and controlling various functions of a laser assembly. The laser controller may include a wavelength tuning circuit for adjusting and locking the wavelength of the external cavity. To perform various monitoring and control functions, the controller may include circuitry for monitoring various parameters associated with operation of the laser, such as temperature indicating signals and/or signals from light detectors such as photodiodes.
    Type: Application
    Filed: January 30, 2003
    Publication date: July 24, 2003
    Applicant: Intel Corporation
    Inventors: George D. Pontis, Douglas A. Sprock, Robert Carney
  • Patent number: 6587286
    Abstract: The present invention comprises of a circular prism having beveled periphery and center faces cooperating with multiple other prisms to form a light capacitor. The present invention allows a user to collect and hold the light in a storage-type device for use in a concentrated way when desired.
    Type: Grant
    Filed: August 27, 1999
    Date of Patent: July 1, 2003
    Inventor: James A. Townsend
  • Publication number: 20030112843
    Abstract: A multi-frequency light source is disclosed. In one disclosed aspect, the light source may comprise a gain region defined by a first and second mirror. The gain region may have corresponding resonant modes. An external cavity defined by a third mirror and said second mirror is also provided, with the external cavity having a plurality of resonant modes. The second mirror may be terminated with a layer of high reflectivity. In a further aspect, the second mirror may be terminated with an antiphase layer.
    Type: Application
    Filed: July 3, 2002
    Publication date: June 19, 2003
    Applicant: Siros Technology, Inc.
    Inventors: Robert L. Thornton, John E. Epler
  • Publication number: 20030108079
    Abstract: A fiber-grating semiconductor laser with tunability is provided, which varies a output wavelength easily. The fiber-grating semiconductor laser with tunability is the hybrid integrated module on a substrate. It consists of a semiconductor laser as a gain medium and a Bragg-grating-written fiber held in a wavelength-tuning unit. (deletion) The wavelength-tuning unit can apply compression or elongation in the fiber grating for wavelength tunability.
    Type: Application
    Filed: March 29, 2002
    Publication date: June 12, 2003
    Inventors: Hyun-Woo Song, Je Ha Kim
  • Publication number: 20030103544
    Abstract: A semiconductor laser device comprises an optical fiber having an optical fiber grating formed therein, a semiconductor laser having an active layer with a single quantum well, for emitting laser light, and a coupling optical system for coupling the laser light emitted out of the semiconductor laser into the optical fiber. The coupling optical system can include a narrow-band filter for adjusting an incident angle of the laser light emitted out of the semiconductor laser. The optical fiber grating can have a reflection bandwidth wider than or substantially equal to a 3 dB bandwidth of the gain of the semiconductor laser or a spectrum full width at half maximum of the laser light of the semiconductor laser.
    Type: Application
    Filed: February 13, 2002
    Publication date: June 5, 2003
    Inventors: Kiyohide Sakai, Yuuhiko Hamada, Takeshi Fujita, Yasuaki Yoshida, Kimio Shigihara, Tatsuo Hatta
  • Publication number: 20030091088
    Abstract: A laser apparatus capable of suppressing an influence of return light with respect to an optical output without causing an increase of a number of parts, an enlargement of the entire apparatus, or an increase of a power consumption, including a semiconductor laser having an optical resonator provided with a pair of opposing reflection mirrors, in which a resonator length is set to Lin, constituted so as to obtain a constant optical output from the optical resonator under constant drive conditions, and set so that reflectivities Rf and Rr of the reflection mirrors absorb a change of an output light intensity due to a change of the phase of the return light.
    Type: Application
    Filed: November 16, 1998
    Publication date: May 15, 2003
    Inventors: MASAKAZU UKITA, MASATO DOI, KAZUO HONDA
  • Publication number: 20030086468
    Abstract: An external cavity semiconductor laser comprises a grating fiber and a semiconductor optical amplification element. The grating fiber has a Bragg grating and an optical waveguide. The Bragg grating has a frequency fFG and exhibits a maximum reflectivity thereat. The Bragg grating is optically coupled to the optical waveguide. In the external cavity semiconductor laser.
    Type: Application
    Filed: August 9, 2002
    Publication date: May 8, 2003
    Inventors: Takashi Kato, Jun-ichi Hashimoto, Naoyuki Yamabayashi
  • Publication number: 20030053511
    Abstract: A multiple reflectivity band reflector (MRBR) includes a stack of dielectric layers, arranged so that the reflector has a reflectivity profile comprising a plurality of reflectivity bands, e.g. at least first and second wavelength bands with reflectivity above a lasing threshold reflectivity, separated by a third wavelength band between the first and second wavelength bands having reflectivity below the lasing threshold reflectivity. A laser having at least a first mirror and an MRBR as the second mirror has a laser cavity, at least a portion of which is defined by the first mirror and the MRBR. An active region located within the laser cavity contains a material that is capable of stimulated emission at one or more wavelengths in the first and second wavelength bands. The gain spectrum of the laser is adjusted to select one of the first and second wavelength bands, thereby providing for lasing at a wavelength within the selected wavelength band. The laser may be, e.g.
    Type: Application
    Filed: July 18, 2002
    Publication date: March 20, 2003
    Applicant: APPLIED OPTOELECTRONICS, INC.
    Inventors: James N. Baillargeon, Wen-Yen Hwang, Klaus Alexander Anselm, Chih-Hsiang Lin
  • Patent number: 6526073
    Abstract: A laser system includes a travelling-wave active laser-resonator arranged for generating laser-radiation having a first wavelength and arranged such that the first-wavelength radiation circulates in only one direction therein. An optically-nonlinear element is positioned in the travelling-wave laser-resonator such that the first-wavelength radiation circulates therethrough. Radiation having a second-wavelength is injected into the optically-nonlinear crystal such that the first-wavelength radiation and second-wavelength radiation mix therein, thereby generating radiation having the sum-frequency of the first and second-wavelength radiations. The sum-frequency radiation from the optically-nonlinear element is delivered from the laser system as output-radiation. In one example, the travelling-wave resonator has a YVO4 gain medium generating radiation having a wavelength of about 1064 nm. The optically-nonlinear crystal is a CLBO crystal.
    Type: Grant
    Filed: December 30, 1999
    Date of Patent: February 25, 2003
    Assignee: Coherent, Inc.
    Inventors: Luis A. Spinelli, Briggs Atherton
  • Publication number: 20030035459
    Abstract: A semiconductor laser includes first and second laser cavities. The first and second cavities share a common optical gain medium and lase at different wavelengths.
    Type: Application
    Filed: August 14, 2001
    Publication date: February 20, 2003
    Inventors: William Larry Wilson, Jin Z. Zhang
  • Patent number: 6515305
    Abstract: A vertical cavity surface emitting laser, includes a substrate, a lower mirror stacked adjacent the substrate, an active region operably coupled to the lower mirror stack, and an upper mirror operably coupled to the active region, opposite the lower mirror. The lower mirror, active region, and upper mirror are arranged in a vertical stack to form a laser. A plurality of spaced apart regions of increased refractive index which extend in a vertical direction at least partially through the vertical stack to promote single mode confinement in the stack.
    Type: Grant
    Filed: September 17, 2001
    Date of Patent: February 4, 2003
    Assignee: Regents of the University of Minnesota
    Inventor: Anand Gopinath
  • Publication number: 20030016721
    Abstract: An apparatus has first and second light sources, a plurality of filters, and an optical switch. The light sources output a light beam having a spectrum determined by a gain band thereof. The plurality of filters each have a reflection band included in the gain band. The optical switch selectively couples the filters to the light source. The first and second light sources provide pumping light to a single transmission line. The first and second filters are configured so as to not reflect signal light to be amplified.
    Type: Application
    Filed: August 8, 2002
    Publication date: January 23, 2003
    Applicant: Fujitsu Limited
    Inventors: Norihisa Naganuma, Norifumi Shukunami
  • Publication number: 20030016709
    Abstract: A fixed wavelength, external cavity semiconductor laser comprises a semiconductor laser gain medium and an intra-cavity filter having a filter function specifying a frequency of operation of the laser. This distinguishes it from distributed feedback Bragg reflector systems in which the wavelength of operation is dictated by the semiconductor Bragg grating, drive current, and temperature. A cavity length modulation system is further provided that modulates an optical length of the cavity to change the spectral locations of longitudinal modes of the cavity relative to the filter function. One important advantage of the present invention is that it can be deployed without a thermoelectric (TE) cooler. Specifically, the intra-cavity filter material in combination with the cavity length controller, allow a mode of cavity to be located at the filter function.
    Type: Application
    Filed: July 19, 2001
    Publication date: January 23, 2003
    Applicant: AXSUN Technologies, Inc.
    Inventor: Dale C. Flanders
  • Patent number: 6507597
    Abstract: Multiwavelength laser source transmitting a luminous flux including as many amplifier wave-guides as potential transmission wavelengths, a collimation optic system for collimating the beams transmitted by the wave-guides, a network and a retroreflector making up the network, a dispersive retroreflecting device that defines with each wave-guide, an external resonating cavity, whereas each wave-guide has an inner face and an outer face with respect to its associated cavity. A Fabry-Perot interferometer with reduced fine adjustment is placed in the cavity between the collimation optic system and the network, whereby the interferometer is tilted with respect to the axis of the cavity and forms a little selective filter, whose variation law of the wavelength transmitted in relation to the angle of incidence is identical with that of the dispersive retroreflecting device.
    Type: Grant
    Filed: December 3, 1999
    Date of Patent: January 14, 2003
    Assignee: Photonetics
    Inventors: Philippe Graindorge, Philippe Martin, Bernard Laloux, Hervé Lefevre
  • Patent number: 6507595
    Abstract: A vertical-cavity surface-emitting laser device (VCSEL) comprises a plurality of VCSEL elements arranged on a common substrate, each VCSEL element comprising first mirror means and second mirror means, each having a predefined reflectivity at a predetermined wavelength, for forming an optical resonator for said wavelength, and a laser active region disposed between said first and second mirror means. In addition, the VCSEL device comprises a grid layer having a plurality of openings corresponding to the respective VCSEL elements and a contact layer having a predetermined thickness, said contact layer being interposed between each of said first mirror means and said grid layer, wherein an optical thickness of said contact layer and a reflectivity and an absorption of said grid layer is selected so as to provide an effective reflectivity of each of said first mirror means depending on said grid layer and being different for areas covered by the grid and areas corresponding to said grid openings.
    Type: Grant
    Filed: November 17, 2000
    Date of Patent: January 14, 2003
    Assignee: Avalon Photonics
    Inventors: Elyahou Kapon, Fabrice Monti di Sopra, Marcel Brunner
  • Patent number: 6442186
    Abstract: A stable multi-fold telescopic resonator is applied to a slab laser to provide a high power laser beam of a high optical quality. The current invention could be applied to both waveguide and free-space slab lasers with either gas or solid-state active media. A reduced sensitivity to misalignment is achieved through the use of two short-radii concave folding mirrors forming a nearly-confocal or confocal optical resonator. In order to obtain a nearly-symmetrical output beam profile from the large thickness slab lasing medium, the resonator includes a slit diaphragm(s), positioned between the slab and resonator mirrors and aimed to eliminate higher order laser modes in the direction transverse to the plane of the slab. Furthermore, a three mirror multi-fold telescopic resonator is provided by substituting one of the resonator mirrors with a surface of one of the folding mirrors.
    Type: Grant
    Filed: September 17, 1999
    Date of Patent: August 27, 2002
    Inventor: Peter Vitruk
  • Patent number: 6411640
    Abstract: A distributed feedback semiconductor laser of the present invention includes a waveguide with an active layer and a diffraction grating, and a first phase shift region formed in the waveguide. The waveguide extends along a cavity-axial direction and is defined such that propagation of light in two different polarization modes is permitted in the waveguide. The first phase shift region extends along the cavity-axial direction and has a polarization dependency that an effective refractive index for propagation light of the first phase shift region differs from an effective refractive index for propagation light of a region of the waveguide other than the first phase shift region such that a phase shift of a quarter wavelength of the propagation light is created for one of the two polarization modes and a phase shift of a half wavelength of the propagation light is created for the other of the two polarization modes in the first phase shift region.
    Type: Grant
    Filed: April 15, 1999
    Date of Patent: June 25, 2002
    Assignee: Canon Kabushiki Kaisha
    Inventor: Koichiro Nakanishi
  • Patent number: 6404947
    Abstract: A demultiplexer according to the present invention includes a photonic crystalline layer, which is formed on the principal surface of a semiconductor substrate and transmits an incoming light beam with a predetermined wavelength. A wavelength at an edge of a photonic band of the photonic crystalline layer changes in a direction parallel to the principal surface of the substrate.
    Type: Grant
    Filed: November 15, 2000
    Date of Patent: June 11, 2002
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Kenichi Matsuda
  • Patent number: 6404798
    Abstract: A laser source with an optical resonator includes a laser gain medium with a low reflective first facet emitting a laser beam within the optical resonator. A wavelength dependent mirror receives the laser beam and reflects back a wavelength separated laser beam. A beam splitter divides the wavelength separated laser beam into a feedback beam directed toward the laser gain medium and a first output beam to be coupled out of the optical resonator. As a first improvement, the laser gain medium includes a second facet which is partly reflective, so that the second facet emits a second output beam of the laser source. As a second improvement, the laser source further includes a mirror arranged in a way that a beam diffracted by the wavelength dependent mirror is reflected back and again diffracted by the wavelength dependent mirror, so that the twice diffracted beam provides the wavelength separated laser beam.
    Type: Grant
    Filed: December 8, 1998
    Date of Patent: June 11, 2002
    Assignee: Agilent Technologies, Inc.
    Inventors: Edgar Leckel, Emmerich Mueller, Clemens Rueck
  • Patent number: 6389044
    Abstract: A multi-wavelength laser (10) includes an optical loop (20) having a single optical cavity that supports a plurality of longitudinal modes, wherein the optical loop has a common gain medium (25) to supply the necessary optical gain to provide for a plurality of lasing longitudinal modes at a plurality of lasing wavelengths. A wavelength selector (30) is insertable into the optical loop within the optical path for selecting at least one lasing longitudinal mode (35) from the plurality of longitudinal modes. Although not exclusively, the multi-wavelength laser (10) is usable for WDM interferometric sensing (240).
    Type: Grant
    Filed: May 31, 2000
    Date of Patent: May 14, 2002
    Assignee: Corning Incorporated
    Inventor: James A. Smith
  • Patent number: 6365427
    Abstract: The present invention relates to a semiconductor laser device and a method for fabrication thereof, wherein the semiconductor laser device exhibits an improved mode selectivity.
    Type: Grant
    Filed: February 9, 2000
    Date of Patent: April 2, 2002
    Assignee: Avalon Photonics Ltd.
    Inventors: Hans Peter Gauggel, Karl Heinz Gulden
  • Patent number: 6356575
    Abstract: A dual cavity multifunction laser comprising a diode-pumped, contact cooled, slab laser head that supports two different length unstable resonators. The laser produces short (<8 ns), low energy 1 &mgr;m pulses or long (>15 ns), higher energy 1 &mgr;m pulses from the same laser system at different repetition rates, if desired. The output from each resonator can be separately optimized for different operating modes such as target designation and target profiling. The unstable resonators use independently optimized super Gaussian output couplers to generate high quality beams for each of the high and low pulse energy modes. The resonators also share a common bounce path to minimize intracavity losses and thermally induced birefringence for both resonators.
    Type: Grant
    Filed: July 6, 1999
    Date of Patent: March 12, 2002
    Assignee: Raytheon Company
    Inventor: Joseph M. Fukumoto
  • Patent number: 6327281
    Abstract: According to the invention, a method and apparatus for generating an Nth harmonic frequency beam (N>2) is provided. A laser fundamental resonator cavity generates a preselected fundamental beam. The laser cavity comprises two fundamental beam reflective mirrors, which define the laser cavity, and a lasing medium. A 2nd or 3rd harmonic cavity is at least partially separate from and the fundamental cavity and at least partially overlaps the fundamental cavity. The harmonic cavity is formed between 2nd or 3rd harmonic beam reflective surfaces and contains a 2nd or 3rd harmonic generator, preferably a harmonic nonlinear crystal. The beam from the fundamental cavity is directed into the harmonic cavity to incident on the harmonic nonlinear crystal for converting at least a portion of the fundamental beam to a harmonic beam.
    Type: Grant
    Filed: October 9, 1999
    Date of Patent: December 4, 2001
    Assignee: Photonics Industries International, Inc.
    Inventor: Yusong Yin
  • Patent number: 6324203
    Abstract: A light source for an exposure device associated with an optical lithographic system is disclosed. The light source includes a structural body having slots for receiving a plurality of laser elements. The laser elements are modular. Thus, they can be removed and installed separately, which facilitates ease of maintenance. The laser elements have a semiconductor laser that pumps a solid-state laser that is subjected to nonlinear optical crystals that convert the laser beam to smaller wavelength light to produce polarized UV laser light for use in optical lithography. The laser light from each laser element is linearly polarized. The laser elements are located in the structural body in different orientations so as to orient their respective directions of polarization different from each other so as to prevent dissimilar line widths of linear features of lithographically produced substrates that use laser light sources.
    Type: Grant
    Filed: June 12, 1998
    Date of Patent: November 27, 2001
    Assignee: Nikon Corporation
    Inventor: Soichi Owa
  • Patent number: 6324194
    Abstract: A laser system includes a travelling-wave active laser-resonator arranged for generating laser-radiation having a first wavelength and arranged such that the first-wavelength radiation circulates in only one direction therein. An optically-nonlinear element is positioned in the travelling-wave laser-resonator such that the first-wavelength radiation circulates therethrough. Radiation having a second-wavelength is injected into the optically-nonlinear crystal such that the first-wavelength radiation and second-wavelength radiation mix therein, thereby generating radiation having the sum-frequency of the first and second-wavelength radiations. The sum-frequency radiation from the optically-nonlinear element is delivered from the laser system as output-radiation. In one example, the travelling-wave resonator has a YVO4 gain medium generating radiation having a wavelength of about 1064 nm. The optically-nonlinear crystal is a CLBO crystal.
    Type: Grant
    Filed: December 30, 1999
    Date of Patent: November 27, 2001
    Assignee: Coherent, Inc.
    Inventors: Luis A. Spinelli, Briggs Atherton
  • Publication number: 20010036217
    Abstract: The present invention features a reconfigurable resonant cavity specifically for use with a slot radiator. A series of internal planes with frequency-selective materials disposed on their top surfaces, in conjunction with switchable shorting pins, is used to reconfigure the cavity's resonant frequency. PIN diodes, MEMS or other photonically or electrical activated switching devices may be used to selectively “activate” shorting pins. A single resonant cavity may be electrically reconfigured to operate at two, three, or even more different frequency bands.
    Type: Application
    Filed: March 15, 2001
    Publication date: November 1, 2001
    Inventors: David E. Kopf, Zane Lo
  • Patent number: 6295308
    Abstract: An optical transmitter providing the benefits of both filter-locked and wavelength-locked lasers is disclosed by modifying an external cavity (32) for the integration of an optical modulator (14). The external cavity (32) provides a round-trip path for light travel. A substrate (24) is connected to the external cavity (32) where at least one gain element (16) and the optical modulator (14) are integral with the substrate (24). A partial reflector (40) is also integral with the substrate (24) and couples the at least one gain element (16) with the optical modulator (14).
    Type: Grant
    Filed: August 31, 1999
    Date of Patent: September 25, 2001
    Assignee: Corning Incorporated
    Inventor: Chung-en Zah
  • Patent number: 6295304
    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. Multiple resonators may also be pumped by a single pump source by locating each in a different branch of a multiple branch directional coupler. If the resonators are constructed to couple their outputs away from the coupler, a plurality of different laser outputs each having a different wavelength and equal output powers is provided.
    Type: Grant
    Filed: February 15, 2000
    Date of Patent: September 25, 2001
    Assignee: SDL, Inc.
    Inventors: Thomas L. Koch, Stephen G. Grubb
  • Patent number: 6292505
    Abstract: In a laser apparatus, when no voltage is applied to optical modulator, a first linearly polarized component of a laser beam which passes through a polarization control mirror causes a laser oscillation in a first laser resonator and a laser beam is output from a second reflecting mirror. When a pulsed voltage is applied to the optical modulator, a second linearly polarized component of the laser beam reflected by the polarization control mirror passes through the optical modulation means and causes a Q-switched laser oscillation in a second laser resonator. In this case, the first linearly polarized component passes through the polarization control mirror and is output from the second reflecting mirror. This technique makes it possible to combine a Q-switched laser apparatus with a non-Q-switched laser apparatus without causing the power of the laser beam to exceed a maximum allowable limit that an electrooptical modulator can handle.
    Type: Grant
    Filed: April 5, 1999
    Date of Patent: September 18, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yushi Takenaka, Jun-ichi Nishimae, Yukio Satoh
  • Patent number: 6292504
    Abstract: Dual-cavity resonators that may be optimized for multiple functions (operating modes). The dual-cavity resonators provide a first set of operating modes that exhibits low repetition rates (5-20 Hz), high energy per pulse, and long, pulse-width, and a second set of operating modes that exhibits high repetition rates (100-2000 Hz), low energy per pulse, and short pulse-width.
    Type: Grant
    Filed: March 16, 1999
    Date of Patent: September 18, 2001
    Assignee: Raytheon Company
    Inventor: Maurice J. Halmos
  • Patent number: 6282214
    Abstract: In a wavelength multiplexing light source used in an optical wavelength division multiplexing (WDM) transmission system and the like, at least three semiconductor lasers of single longitudinal mode have oscillation frequencies outside of their pull-in range at a normal injection locking without a modulation side band, an output light of a first semiconductor laser is injected in one way into a second semiconductor laser having an oscillation frequency adjacent to that of the first o semiconductor laser through a first one-way optical injection means to generate a modulation side band. The output light of the second semiconductor laser is then injected in one way into a third semiconductor laser having an oscillation frequency adjacent to that of the second semiconductor laser through a second one-way optical injection means to generate the modulation side band for an injection locking.
    Type: Grant
    Filed: March 4, 1999
    Date of Patent: August 28, 2001
    Assignees: Fujitsu Limited, Nagoya University
    Inventors: Ryosuke Goto, Kazuo Yamane, Toshio Goto, Masakazu Mori
  • Patent number: 6226311
    Abstract: A laser module (1) comprises a Fabry-Perot cavity active element (2) with a facet (3) bearing an anti-reflection coating and an external cavity made by an optical fibre Bragg grating (5) with low reflectivity. This grating (5) presents a non-uniform profile of modulation of the refractive index, asymmetrical in the direction of the grating length, such as to give rise to a position of the equivalent mirror plane that is offset towards the end of the grating (5) that is closer to the active element (2).
    Type: Grant
    Filed: March 9, 1999
    Date of Patent: May 1, 2001
    Assignee: Agilent Technologies, Inc.
    Inventors: Marina Meliga, Roberto Paoletti, Marco Scofet, Luigi Tallone
  • Patent number: 6205161
    Abstract: The invention concerns a method of operating a laser diode (2) producing a beam (9) whose intensity is controlled by a control signal and which is directed along a first beam path (10) at the target surface (5), stray reflections from the target surface (50 which are unstable with respect to the diode (2) in time and/or space acting on the diode (2). An element (19, 28, 31, 37, 38) which is stable in time and with respect to the diode (2) in space is used to feed part of the light emitted by the diode back along a second beam path (11) to the active zone (42) of the diode (2) so that the diode (2) is kept in a state of coherence collapse.
    Type: Grant
    Filed: August 21, 1998
    Date of Patent: March 20, 2001
    Assignee: AGFA-Gevaert Aktiengesellschaft
    Inventor: Franz Kappeler
  • Patent number: 6188707
    Abstract: A laser diode bar mounting structure includes a dielectric substrate with an overlying conductor, and diode bar spaces through the conductor layer to support laser diode bars within them. The bar spaces are configured with parallel upper sidewalls and flared out or expanded bottoms to dissipate capillary action of solder under the diode bars.
    Type: Grant
    Filed: December 15, 1998
    Date of Patent: February 13, 2001
    Inventors: Timothy L. Irwin, Judith B. Irwin
  • Patent number: 6154318
    Abstract: Negative Group-delay-dispersion mirror (NGDD-mirror) multilayer structures include a generally-orderly arrangement of layers or groups of layers in which the function of certain individual layers or groups of layers can be recognized and defined. The structures are broadly definable as a rear group of layers which are primarily responsible for providing a desired reflection level and reflection bandwidth together with a low and smoothly varying reflection phase-dispersion, and a front group of layers which are primarily responsible for producing high reflection phase-dispersion necessary for providing a desired NGDD level and bandwidth. The front group of layers relies on multiple resonant trapping mechanisms such as two or more effective resonant-cavities, employing one or more sub-quarter-wave layers to shape the phase-dispersion for providing a substantially-constant NGDD.
    Type: Grant
    Filed: November 16, 1999
    Date of Patent: November 28, 2000
    Assignee: Coherent, Inc.
    Inventors: R. Russel Austin, R. Ian Edmond
  • Patent number: 6144683
    Abstract: An infrared laser structure is stacked on top of a red laser structure with both having an inverted or p-side down orientation. The red/infrared stack laser structure is inverted and wafer fused to a blue laser structure to form a red/infrared/blue monolithic laser structure. The top semiconductor layer of the inverted red/infrared stack laser structure is a GaInP fusion bonding layer which will be wafer fused to the top semiconductor layer of the blue laser structure which is a GaN cladding/contact layer.
    Type: Grant
    Filed: January 7, 1998
    Date of Patent: November 7, 2000
    Assignee: Xerox Corporation
    Inventor: Philip D. Floyd
  • Patent number: 6141369
    Abstract: An intracavity frequency-doubled laser has a standing-wave resonator including a gain medium and an optically-nonlinear crystal. The optically-nonlinear crystal has a large walkoff-angle between the fundamental laser-beam and the frequency-doubled beam created by passage of the fundamental laser-beam through the crystal. The optically-nonlinear crystal is arranged such that the walkoff-angle provides for lateral, spatial separation of a fundamental and a corresponding frequency-doubled beam outside the crystal, and for separation of counterpropagating frequency-doubled beams from each other. The spatial separation of the counterpropagating frequency-doubled beams reduces amplitude fluctuation caused by interference between the beams. A physical stop is used to prevent one of the frequency-doubled beams from entering the gain medium. This prevents that beam from spuriously pumping the gain medium and thus serves to further reduce amplitude fluctuation.
    Type: Grant
    Filed: September 2, 1998
    Date of Patent: October 31, 2000
    Assignee: Coherent, Inc.
    Inventors: Wolf Seelert, Vasiliy Ostroumov
  • Patent number: 6130899
    Abstract: One facet of each of a set of N semiconductor laser chips is provided with an antireflection coating through which the chip emission is coupled, via a wavelength multiplexer, with a partially reflecting Bragg reflector providing an N-way wavelength multiplexed laser output for pumping an optical amplifier. The wavelength multiplexer may be constituted by a cascade arrangement of Mach-Zehnders.
    Type: Grant
    Filed: December 12, 1996
    Date of Patent: October 10, 2000
    Assignee: Nortel Networks Corporation
    Inventors: Richard Edward Epworth, Jonathan Paul King
  • Patent number: 6104740
    Abstract: An an infrared laser structure has an inverted or p-side down orientation. The infrared laser structure is inverted and wafer fused to a blue laser structure to form an infrared/blue monolithic laser structure. The top semiconductor layer of the inverted infrared stack laser structure is a GaInP fusion bonding layer which will be wafer fused to the top semiconductor layer of the blue laser structure which is a GaN cladding/contact layer.
    Type: Grant
    Filed: January 7, 1998
    Date of Patent: August 15, 2000
    Assignee: Xerox Corporation
    Inventor: Philip D. Floyd
  • Patent number: 6101205
    Abstract: A plate of metal is bonded to a plate of and electrical insulator and the metal is cut through into a plurality of parallel channels, or recesses, each of a dimension to receive a laser diode (bar). A laser diode is positioned in each of the channels and a solder preform, positioned on the top of the laser diode bars. Is heated to flow around each laser diode bar to secure it in place. A highly manufacturable laser diode assembly having a higher heat capacity results for bonding to a heat sink.
    Type: Grant
    Filed: March 31, 1998
    Date of Patent: August 8, 2000
    Assignee: Opto Power Corporation
    Inventors: Stewart Wayne Wilson, David Pace Caffey
  • Patent number: 6097742
    Abstract: External-cavity optically-pumped semiconductor lasers (OPS-lasers) including an OPS-structure having a mirror-structure surmounted by a surface-emitting, semiconductor multilayer (periodic) gain-structure are disclosed. The gain-structure is pumped by light from diode-lasers. The OPS-lasers can provide fundamental laser output-power of about two Watts (2.0 W) or greater. Intracavity frequency-converted arrangements of the OPS-lasers can provide harmonic laser output-power of about one-hundred milliwatts (100 mW) or greater, even at wavelengths in the ultraviolet region of the electromagnetic spectrum. These high output powers can be provided even in single axial-mode operation.
    Type: Grant
    Filed: March 5, 1999
    Date of Patent: August 1, 2000
    Assignee: Coherent, Inc.
    Inventors: Andrea Caprara, Juan L. Chilla, Luis A. Spinelli
  • Patent number: 6091439
    Abstract: A laser printer is provided printing with a high precision simply and at a high speed, and the laser printer uses a semiconductor laser which can vary the diameter of the emitted light while the light density is held constant. In the laser printer, laser rays emitted from a semiconductor laser are irradiated onto a photoconductor to vary its surface potential to produce a charge pattern particles adhere, and printing is performed by transferring the changed particles to a printing object. The semiconductor laser has a plurality of waveguide type resonators, the emitted beams of the resonators having a spatial superposition, and light emission is possible so that the emitted beams of the resonators having a spatial superposition with respect to each other among the resonators of the semiconductor laser are not substantially superimposed in time.
    Type: Grant
    Filed: November 7, 1997
    Date of Patent: July 18, 2000
    Assignees: Hitachi, Ltd., Hitachi Koki Co., Ltd.
    Inventors: Shinichi Nakatsuka, Susumu Saito, Akira Arimoto
  • Patent number: 6088379
    Abstract: An ultraviolet laser apparatus which generates laser light at 193 nm to 213 nm with high temporal and spatial coherence and relatively high power is disclosed. The UV laser apparatus provides a light source for an exposure device for optical lithography and an aberration measurement interferometer that measures lens wave front aberration. The laser apparatus disclosed herein comprises two lasers having laser resonators that are coincident along a portion of their respective optical paths. A nonlinear optical crystal is located along the shared optical path portion for sum frequency generation of the light of the respective lasers.
    Type: Grant
    Filed: June 9, 1998
    Date of Patent: July 11, 2000
    Assignee: Nikon Corporation
    Inventors: Soichi Owa, Tomoko Ohtsuki
  • Patent number: 6081544
    Abstract: The laser beam produced by the improved precision laser maintains an axial stability of less than 20 micro-radians in the presence of ambient temperature changes and shock and vibration of as much as 100 g's, achieving a new milestone in stability. In the new laser one end of the resonator (7) is hard mounted to the laser bench (13) and the other end of the resonator is mounted to that laser bench by a flexure (17). The flexure is designed to resiliently yield in the presence of thermally induced strain on the bench while retaining sufficient stiffness against foreseeable shock and vibration.
    Type: Grant
    Filed: April 8, 1998
    Date of Patent: June 27, 2000
    Assignee: TRW Inc.
    Inventors: James M. Zamel, Vicko N. Skokandic
  • Patent number: 6078606
    Abstract: A multi-color, multi-pulse laser operating at a number of wavelengths is provided with a like number of cavities to produce a like number of output pulses from a single pumping pulse. The spacing between the pulses is easily controlled by controlling the timing of Q-switches, each in a different cavity, so that information is imparted by the pulse spacing. In a two color embodiment, a beam splitting device is positioned along the longitudinal axis of the laser medium to produce two beams which are directed into different cavity resonators, each tuned to a different wavelength. Reflecting surfaces positioned at the end of each cavity redirect each beam back to the beam splitting device where the beams are spatially recombined and subsequently two pulses, one of one color and the other of the second color, are sequentially coupled out of the laser system.
    Type: Grant
    Filed: March 17, 1975
    Date of Patent: June 20, 2000
    Assignee: Lockheed Martin Corporation
    Inventors: Charles S. Naiman, Stuart D. Pompian