Patents by Inventor David F. Welch

Application number: 20040033004
Abstract: A photonic integrated circuits (PICs), also referred to as opto-electronic integrated circuits (OEICs), and more particularly to a PIC in the form of an optical receiver PIC or RxPIC for use in an optical transport networks. Also, an optical transmitter PIC (TxPIC) is also disclosed in conjunction with an RxPIC in an optical transport network. The chip is cast from an InP wafer and is made from Group III-V elemental materials in the InGaAsP/InP regime with fabrication accomplished through selective metalorganic vapor phase epitaxy (MOVPE) or also known as metalorganic chemical vapor deposition (MOCVD). Integrated on the chip, starting at the input end which is coupled to receive multiplexed optical data signals from an optical transport network is an optical amplifier, an optical demultiplexer, and a plurality of on-chip photodiodes (PDs) each to receive a demultiplexed data signal from the AWG DEMUX for optical-to-electrical signal conversion.
Type: Application
Filed: October 8, 2002
Issued: February 19, 2004
Inventors: David F. Welch, Radhakrishnan L. Nagarajan, Fred A. Kish, Mark J. Missey, Vincent G. Dominic, Atul Mathur, Frank H. Peters, Charles H. Joyner, Richard P. Schneider, Ting-Kuang Chiang
Patent number: 6603595
Abstract: An optical amplifier with a flattened wideband response is obtained by coupling counter-propagating pumping energy into an optical waveguide to cause Raman amplification in the optical waveguide, and by reflecting an amplified signal received from the optical waveguide into an output waveguide using a reflector having a spectral characteristic that is complementary to the spectral gain characteristic of the Raman amplification.
Type: Grant
Filed: June 26, 2002
Issued: August 5, 2003
Assignee: JDS Uniphase Corporation
Inventors: David F. Welch, Robert J. Lang, Edward C. Vail, Mehrdad Ziari
Patent number: 6580552
Abstract: An optical amplifier includes a plurality of optical paths each carrying an optical signal and each including active optical fiber. A shared pump laser is coupled to the plurality of optical paths and provides pump power to the plurality of optical paths to individually amplify the optical signals. The plurality of optical paths includes input and output optical isolators and a coupler for coupling the pump power to the optical path. The active optical fiber is doped with an implant selected from the group of rare earth metals, erbium, ytterbium, and both ytterbium and erbium. A variable attenuator can be connected between the pump laser and the coupler of at least one of the plurality of optical paths or adjacent to the output isolator of one of the optical paths. Another optical amplifier serially couples optical signals to the optical path on a common gain media.
Type: Grant
Filed: August 27, 2001
Issued: June 17, 2003
Assignee: JDS Uniphase Corporation
Inventor: David F. Welch
Application number: 20030099018
Abstract: A digital optical network (DON) is a new approach to low-cost, more compact optical transmitter modules and optical receiver modules for deployment in optical transport networks (OTNs). One important aspect of a digital optical network is the incorporation in these modules of transmitter photonic integrated circuit (TxPIC) chips and receiver photonic integrated circuit (TxPIC) chips in lieu of discrete modulated sources and detector sources with discrete multiplexers or demultiplexers.
Type: Application
Filed: October 8, 2002
Issued: May 29, 2003
Inventors: Jagdeep Singh, Drew D. Perkins, David F. Welch, Mark Yin, Fred A. Kish, Stephen G. Grubb, Robert B. Taylor, Vincent G. Dominic, Matthew L. Mitchell
Application number: 20030095737
Abstract: A photonic integrated circuit (PIC) chip comprising an array of modulated sources, each providing a modulated signal output at a channel wavelength different from the channel wavelength of other modulated sources and a wavelength selective combiner having an input optically coupled to received all the signal outputs from the modulated sources and provide a combined output signal on an output waveguide from the chip. The modulated sources, combiner and output waveguide are all integrated on the same chip.
Type: Application
Filed: October 8, 2002
Issued: May 22, 2003
Inventors: David F. Welch, Vincent G. Dominic, Fred A. Kish, Mark J. Missey, Radhakrishnan L. Nagarajan, Atul Mathur, Frank H. Peters, Robert B. Taylor, Matthew L. Mitchell, Alan C. Nilsson, Stephen G. Grubb, Richard P. Schneider, Charles H. Joyner, Jonas Webjorn, Drew D. Perkins
Application number: 20030095736
Abstract: A monolithic transmitter photonic integrated circuit (TxPIC) chip comprises an array of modulated sources formed on the PIC chip and having different operating wavelengths according to a standardized wavelength grid and providing signal outputs of different wavelengths. Pluralities of wavelength tuning elements are integrated on the chip, one associated with each of the modulated sources. An optical combiner is formed on the PIC chip and the signal outputs of the modulated sources are optically coupled to one or more inputs of the optical combiner and provided as a combined channel signal output from the combiner. The wavelength tuning elements provide for tuning the operating wavelength of the respective modulated sources to be approximate or to be chirped to the standardized wavelength grid. The wavelength tuning elements are temperature changing elements, current and voltage changing elements or bandgap changing elements.
Type: Application
Filed: October 8, 2002
Issued: May 22, 2003
Inventors: Fred A. Kish, Charles H. Joyner, David F. Welch, Jonas Webjorn, Robert B. Taylor, Alan C. Nilsson
Application number: 20030081878
Abstract: A monolithic photonic integrated circuit (PIC) chip comprises an array of modulated sources providing a plurality of channel signals of different wavelengths and an optical combiner coupled to receive the channel signals and produce a combined output of the channel signals. The arrays of modulated sources are formed as ridge waveguides to enhance the output power from the respective modulated sources so that the average output power from the sources is approximately 2 to 4 times higher than in the case of comparable arrays of modulated sources formed as buried waveguides.
Type: Application
Filed: October 8, 2002
Issued: May 1, 2003
Inventors: Charles H. Joyner, Fred A. Kish, Frank H. Peters, Atul Mathur, David F. Welch, Andrew G. Dentai, Damien Lambert, Richard P. Schneider, Mark J. Missey
Application number: 20030076577
Abstract: A lossless optical link in an optical transmission system comprises an optical fiber that is configured to produce Raman gain and provide for Raman distributed gain, via one or more pump sources, along the fiber so that, as an end result, the gain experienced by one or more propagating signals in the fiber link is made fairly uniform along the link or at least a portion of the optical link, such as not vary, for example, no more than five dB along the length of the optical fiber. The several embodiments disclosed provide for different optical pump/component architectures to achieve this end result.
Type: Application
Filed: December 22, 2000
Issued: April 24, 2003
Inventors: Vincent G. Dominic, David F. Welch, Robert G. Waarts, Stuart MacCormack, Mehrdad Ziari, Robert J. Lang, Donald R. Scifres
Application number: 20030039027
Abstract: An optical amplifier includes a plurality of optical paths each carrying an optical signal and each including active optical fiber. A shared pump laser is coupled to the plurality of optical paths and provides pump power to the plurality of optical paths to individually amplify the optical signals. The plurality of optical paths includes input and output optical isolators and a coupler for coupling the pump power to the optical path. The active optical fiber is doped with an implant selected from the group of rare earth metals, erbium, ytterbium, and both ytterbium and erbium. A variable attenuator can be connected between the pump laser and the coupler of at least one of the plurality of optical paths or adjacent to the output isolator of one of the optical paths. Another optical amplifier serially couples optical signals to the optical path on a common gain media.
Type: Application
Filed: August 27, 2001
Issued: February 27, 2003
Inventor: David F. Welch
Patent number: 6489985
Abstract: A laser marking system includes a high power fiber laser with a double clad fiber having a doped core surrounded by an inner pump cladding and providing an optical output for marking; a high power laser diode source for pumping the double clad fiber laser via an input into the inner pump cladding; an optical scanner coupled to receive the marking output from the double clad fiber laser to scan the output over a surface of an article to be marked by sweeping the marking output in one, two or three dimensions to form strokes, the completion of which comprises indicia to be marked on the article surface; and a controller to control the operation of the scanner synchronized with the modulation of the laser diode pump source to initiate the marking output and sweep and modulate the marking optical output in one, two or three dimensions to form strokes comprising the indicia.
Type: Grant
Filed: September 21, 2000
Issued: December 3, 2002
Assignee: JDS Uniphase Corporation
Inventors: Mark A. Brodsky, David F. Welch, Yong Yim
Application number: 20020163713
Abstract: An optical amplifier with a flattened wideband response is obtained by coupling counter-propagating pumping energy into an optical waveguide to cause Raman amplification in the optical waveguide, and by reflecting an amplified signal received from the optical waveguide into an output waveguide using a reflector having a spectral characteristic that is complementary to the spectral gain characteristic of the Raman amplification.
Type: Application
Filed: June 26, 2002
Issued: November 7, 2002
Inventors: David F. Welch, Robert J. Lang, Edward C. Vail, Mehrdad Ziari
Patent number: 6433306
Abstract: A high power laser optical amplifier system for material processing comprises multiple stage fiber amplifiers with rejection of propagating ASE buildup in and between the amplifier stages as well as elimination of SBS noise providing output powers in the range of about 10 &mgr;J to about 100 &mgr;J or more. The system is driven with a time varying drive signal from a modulated semiconductor laser signal source to produce an optical output allowing modification of the material while controlling its thermal sensitivity by varying pulse shapes or pulse widths supplied at a desire repetition rate via modulation of a semiconductor laser signal source to the system to precisely control the applied power application of the beam relative to the thermal sensitivity of the material to be processed. The high power fiber amplifier system has particular utility in high power applications requiring process treatment of surfaces, such as polymeric, organic, ceramic and metal surfaces, e.g.
Type: Grant
Filed: June 2, 2000
Issued: August 13, 2002
Assignee: JDS Uniphase Corp.
Inventors: Stephen G. Grubb, David F. Welch, Raymond Zanoni
Patent number: 6433920
Abstract: An optical amplifier with a flattened wideband response is obtained by coupling counter-propagating pumping energy into an optical waveguide to cause Raman amplification in the optical waveguide, and by reflecting an amplified signal received from the optical waveguide into an output waveguide using a reflector having a spectral characteristic that is complementary to the spectral gain characteristic of the Raman amplification.
Type: Grant
Filed: September 18, 2000
Issued: August 13, 2002
Assignee: JDS Uniphase Corporation
Inventors: David F. Welch, Robert J. Lang, Edward C. Vail, Mehrdad Ziari
Patent number: 6411323
Abstract: Power scaling by multiplexing multiple fiber gain sources with different wave-lengths is useful in printing applications requiring higher optical powers to perform the printing function, such as through thermal inducement in thermal ablation, thermal fusion, thermal diffusion or thermal transfer. A marking system is disclosed using a plurality of laser sources operating at different wavelengths with their respective outputs coupled into a respective single mode fiber. At least one WDM combiner is coupled to receive and combine the laser source outputs into a single output. The combined power single output provides sufficient power intensity to induce thermal marking on a marking medium.
Type: Grant
Filed: December 7, 2000
Issued: June 25, 2002
Assignee: SDL, Inc.
Inventors: Robert G. Waarts, David F. Welch
Patent number: 6404542
Abstract: A pump source for rare earth and Raman amplifiers or for distributed amplification uses two or more light sources to generate two source beams that are combined by a beam combiner to form the output pump beam. In accordance with one embodiment, the light sources are a diode laser array having be two or more monolithic laser stripes providing dual output beams having substantially the same polarization, such as the TE mode. One of the polarized due outputs is rotated 90° and both beams are applied to a birefringent crystal that combines the beams for insertion into an optical fiber or into a rare earth doped fiber or into a fiber capable of Raman amplification via SRS. The power output of each polarization in the combined beam can be measured and used to drive a feedback circuit that controls the current provided to each diode in order to maintain the power in the two polarization components of the output beam equal.
Type: Grant
Filed: July 10, 2000
Issued: June 11, 2002
Assignee: SDL, Inc.
Inventors: Mehrdad Ziari, David F. Welch, Vincent G. Dominic, Bardia Pezeshki, Robert J. Lang
Patent number: 6356574
Abstract: A multistage optical amplifier pumping system with built-in redundant reliability for lightwave communication system provides plural levels of redundancy. A first level of redundancy deals with redundancy in the form of plural primary laser diode sources for pumping a single fiber laser pump source. A second level of redundancy deals with redundancy of a plurality of fiber laser pump sources for pumping a plurality of serially connected injection signal fiber amplifiers forming the multistage amplifier system. If one of fiber pump sources should fail, increased pumping power is available from the remaining fiber pump sources via their respectively connected amplifier stages. A third level of redundancy deals with redundancy in the employment of multiple single mode laser emitters on the same chip or bar sufficiently segmented and/or electrical isolated so as not to interfere with operation of or cause failure to adjacent or neighboring emitters on the same chip or bar.
Type: Grant
Filed: January 29, 1999
Issued: March 12, 2002
Assignee: SDL, Inc.
Inventors: Richard R. Craig, Robert L G. Waarts, David F. Welch, John G. Endriz, Dirk J. Kuizenga, Steven Sanders
Patent number: 6347007
Abstract: A high power laser optical amplifier system for material processing comprises multiple stage fiber amplifiers with rejection of propagating ASE buildup in and between the amplifier stages as well as elimination of SBS noise providing output powers in the range of about 10 &mgr;J to about 100 &mgr;J or more. The system is driven with a time varying drive signal from a modulated semiconductor laser signal source to produce an optical output allowing modification of the material while controlling its thermal sensitivity by varying pulse shapes or pulse widths supplied at a desire repetition rate via modulation of a semiconductor laser signal source to the system to precisely control the applied power application of the beam relative to the thermal sensitivity of the material to be processed. The high power fiber amplifier system has particular utility in high power applications requiring process treatment of surfaces, such as polymeric, organic, ceramic and metal surfaces, e.g.
Type: Grant
Filed: June 2, 2000
Issued: February 12, 2002
Assignee: SDL, Inc.
Inventors: Stephen G. Grubb, David F. Welch, Raymond Zanoni
Patent number: 6345141
Abstract: A double-clad optical fiber has an inner cladding that has a torsional stress induced within it during manufacture. By rotating the fiber preform before curing of the inner cladding layer, a physical stress may be permanently imparted to the inner cladding that interacts with pump energy within the inner cladding layer to encourage mode mixing. As the cladding modes are disturbed by the stresses in the fiber, they are redirected so that the light in them intersects the core.
Type: Grant
Filed: December 5, 2000
Issued: February 5, 2002
Assignee: SDL, Inc.
Inventors: Stephen G. Grubb, David F. Welch
Patent number: 6342405
Abstract: Methods are disclosed for forming Group III-arsenide-nitride semiconductor materials. Group III elements are combined with group V elements, including at least nitrogen and arsenic, in concentrations chosen to lattice match commercially available crystalline substrates. Epitaxial growth of these III-V crystals results in direct bandgap materials, which can be used in applications such as light emitting diodes and lasers. Varying the concentrations of the elements in the III-V crystals varies the bandgaps, such that materials emitting light spanning the visible spectra, as well as mid-IR and near-UV emitters, can be created. Conversely, such material can be used to create devices that acquire light and convert the light to electricity, for applications such as full color photodetectors and solar energy collectors. The growth of the III-V crystals can be accomplished by growing thin layers of elements or compounds in sequences that result in the overall lattice match and bandgap desired.
Type: Grant
Filed: May 23, 2000
Issued: January 29, 2002
Assignee: JDS Uniphase Corporation
Inventors: Jo S. Major, David F. Welch, Donald R. Scifres
Patent number: 6335941
Abstract: A high power laser optical amplifier system for material processing comprises multiple stage fiber amplifiers with rejection of propagating ASE buildup in and between the amplifier stages as well as elimination of SBS noise providing output powers in the range of about 10 &mgr;J to about 100 &mgr;J or more. The system is driven with a time varying drive signal from a modulated semiconductor laser signal source to produce an optical output allowing modification of the material while controlling its thermal sensitivity by varying pulse shapes or pulse widths supplied at a desire repetition rate via modulation of a semiconductor laser signal source to the system to precisely control the applied power application of the beam relative to the thermal sensitivity of the material to be processed. The high power fiber amplifier system has particular utility in high power applications requiring process treatment of surfaces, such as polymeric, organic, ceramic and metal surfaces, e.g.
Type: Grant
Filed: May 15, 2000
Issued: January 1, 2002
Assignee: SDL, Inc.
Inventors: Stephen G. Grubb, David F. Welch, Raymond Zanoni