Patents by Inventor Pak Shing Cho
Pak Shing Cho has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8300229Abstract: This invention relates generally to the systems and methods for standoff trace chemicals detection such as explosives residue and others, and particularly to optical devices and the methods of their use based on sensing of gases and residue materials. This sensing includes detection and measurement of optical absorption spectra and relative concentration of the chemical followed by the chemical identification based on these spectral data. The sensing is based on photothermal interferometry method improved by implementation of coherent optical detection. The coherent optical detection is performed by an integrated polarization-diversity coherent receiver with an electro-optic phase modulator for a local oscillator optical beam. The implementation of pulsed probe sensing and local oscillator optical beams in the coherent detection improves the device with better eye safety performance.Type: GrantFiled: December 11, 2009Date of Patent: October 30, 2012Assignee: CeLight, Inc.Inventors: Pak Shing Cho, Geoffrey Harston
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Publication number: 20120014470Abstract: The method and system are disclosed for automatic feedback control of integrated optical quadrature modulator for generation of optical quaternary phase-shift-keyed signal in coherent optical communications. The method comprises the steps of detecting at least a part of an output optical signal from the QPSK modulator, extracting of a particular portion of the output signal in frequency domain, and processing the signal in frequency domain to optimize the transmission of an optical link. The system and method of optical communications in fiber or free space are disclosed that implement the quadrature data modulator with automatic feedback control.Type: ApplicationFiled: September 23, 2011Publication date: January 19, 2012Inventors: Pak Shing Cho, Jacob Khurgin, Isaac Shpantzer
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Publication number: 20120002211Abstract: This invention relates generally to the systems and methods for standoff trace chemicals detection such as explosives residue and others, and particularly to optical devices and the methods of their use based on sensing of gases and residue materials. This sensing includes detection and measurement of optical absorption spectra and relative concentration of the chemical followed by the chemical identification based on these spectral data. The sensing is based on photothermal interferometry method improved by implementation of coherent optical detection. The coherent optical detection is performed by an integrated polarization-diversity coherent receiver with an electro-optic phase modulator for a local oscillator optical beam. The implementation of pulsed probe sensing and local oscillator optical beams in the coherent detection improves the device with better eye safety performance.Type: ApplicationFiled: December 11, 2009Publication date: January 5, 2012Inventors: Pak Shing Cho, Geoffrey Harston
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Patent number: 8050351Abstract: The method and system are disclosed for automatic feedback control of integrated optical quadrature modulator for generation of optical quaternary phase-shift-keyed signal in coherent optical communications. The method comprises the steps of detecting at least a part of an output optical signal from the QPSK modulator, extracting of a particular portion of the output signal in frequency domain, and processing the signal in frequency domain to optimize the transmission of an optical link. The system and method of optical communications in fiber or free space are disclosed that implement the quadrature data modulator with automatic feedback control.Type: GrantFiled: February 27, 2007Date of Patent: November 1, 2011Assignee: CeLight, Inc.Inventors: Pak Shing Cho, Jacob Khurgin, Isaac Shpantzer
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Patent number: 8009294Abstract: A photo-thermal, interferometric spectroscopy system is disclosed that provides information about a chemical, such as explosives and the like, at a remote location. It may be used for solid residue detection on a surface. The system includes a novel light detector system with a matrix of optical elements focusing portions of a received light beam on input waveguides of an optical combiner. The combiner adjusts the phases of the received beam portions and combines them together to maximize the intensity of an output beam. The output beam is detected by a detector, and information about at least one of, absorption spectrum and concentration of the chemical is recovered. In the preferred embodiment the detector is a coherent detector based on 90-degrees optical hybrid.Type: GrantFiled: January 29, 2009Date of Patent: August 30, 2011Assignee: CeLight, Inc.Inventors: Isaac Shpantzer, Jacob Khurgin, Arkady Kaplan, Pak Shing Cho, Yaakov Achiam
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Patent number: 8009295Abstract: This invention relates generally to the systems and methods for chemicals detection such as explosives and others, and more particularly to optical devices and the methods of their use based on sensing of gases and residue materials. This sensing includes detection of optical spectrum and relative concentration of the chemical followed by the chemical identification based on these data. The sensing is based on photothermal interferometry method modified by implementation of coherent optical detection using a balanced receiver, where the incoming optical signal is mixed with a local oscillator beam. An additional phase shift is embedded in the local oscillator beam for adaptively negating the background noise in the incoming optical signal thus improving the system performance.Type: GrantFiled: February 24, 2010Date of Patent: August 30, 2011Assignee: CeLight, Inc.Inventor: Pak Shing Cho
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Patent number: 7995925Abstract: An optical beam combiner is provided, which allows efficient collection of light for various applications: non-line of sight and free space optical communications, remote sensing, optical imaging and others. A multitude of transverse scattered optical beam portions is captured by the multi-aperture array positioned perpendicular to the beam projection direction. These beam portions are combined first into a single optical waveguide with minimal loss of power. This is achieved by modulating the beam portions phase and coupling ratio of couplers in the optical beam combiner tuned to maximize the final output power. The data is recovered from the received optical beam using coherent detection.Type: GrantFiled: February 13, 2009Date of Patent: August 9, 2011Assignee: CeLight, Inc.Inventors: Pak Shing Cho, Isaac Shpantzer, Jacob Khurgin
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Patent number: 7974543Abstract: A device for phase distortion compensation across an optical beam is provided. The device is a part of an optical receiver, which can be used in free space optical communications, remote sensing, optical imaging and others. 2M inputs of the combiner interfere with each other via a system of tunable coupled waveguides. The phases in interleaved waveguides of the combiner are adjusted to maximize the resulting output signal. The combiner may be used for coherent communication in combination with a balanced 90° hybrid. Integrated solutions for the proposed device are provided.Type: GrantFiled: December 9, 2008Date of Patent: July 5, 2011Assignee: CeLight, Inc.Inventors: Jacob Khurgin, Isaac Shpantzer, Arkady Kaplan, Pak Shing Cho
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Patent number: 7961997Abstract: An optical beam combiner is provided, which allows efficient collection of light for various applications: non-line of sight and free space optical communications, remote sensing, optical imaging and others. A multitude of optical beam portions is captured by a space diversity receiver that includes an optical beam combiner, which has a tree-like topology with interconnected waveguides, electro-optic phase shifters, and directional couplers. For each of the beam portions the phase of the phase shifter and the coupling ratio of coupler in the optical beam combiner are tuned sequentially to maximize the final output power in the final optical waveguide. A portion of the final output beam is used for the power detection and forming a feedback signal for the phases and coupling ratios adjustment. The data or information is recovered from the received final optical beam using coherent detection.Type: GrantFiled: February 20, 2009Date of Patent: June 14, 2011Assignee: CeLight, Inc.Inventors: Pak Shing Cho, Jacob Khurgin, Isaac Shpantzer
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Patent number: 7949262Abstract: An optical beam combiner is provided, which allows efficient collection of light for various applications: non-line of sight and free-space optical communications, remote sensing, optical imaging and others. A multitude of transverse scattered optical beam portions is captured by the multi-aperture array positioned perpendicular to the beam projection direction. These beam portions are combined first into a single optical waveguide with modulating the beam portions phase and coupling ratio of directional couplers in the optical beam combiner tuned to maximize the final output power. A portion of the output beam is used for the power detection and forming a feedback signal for the phases and coupling ratios adjustment. The data is recovered from the received optical beam using coherent detection.Type: GrantFiled: February 25, 2009Date of Patent: May 24, 2011Assignee: CeLight, Inc.Inventors: Pak Shing Cho, Jacob Khurgin, Isaac Shpantzer
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Publication number: 20100290054Abstract: This invention relates generally to the systems and methods for chemicals detection such as explosives and others, and more particularly to optical devices and the methods of their use based on sensing of gases and residue materials. This sensing includes detection of optical spectrum and relative concentration of the chemical followed by the chemical identification based on these data. The sensing is based on photothermal interferometry method modified by implementation of coherent optical detection using a balanced receiver, where the incoming optical signal is mixed with a local oscillator beam. An additional phase shift is embedded in the local oscillator beam for adaptively negating the background noise in the incoming optical signal thus improving the system performance.Type: ApplicationFiled: February 24, 2010Publication date: November 18, 2010Inventor: Pak Shing Cho
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Patent number: 7801395Abstract: An optical device is provided with first and second inputs. A first coupler coupled is coupled to the first input and produces at least a first and second output. A second coupler is coupled to the second input and produces at least a first and second output. A third coupler is coupled to the first output of the first coupler and to the first output of the second coupler. A fourth coupler is coupled to the second output of the first coupler and to the second output of the second coupler. First and second crossing waveguides are provided with an angle selected to minimize crosstalk and losses between the first and second cross waveguides. The first crossing waveguide connects one of the first or second outputs from the first coupler with an input of the fourth coupler. The second crossing waveguide connects one of the first or second outputs from the second coupler with an input of the third coupler. A first phase shifter is coupled to the first and second waveguides.Type: GrantFiled: November 12, 2007Date of Patent: September 21, 2010Assignee: CeLight, Inc.Inventors: Isaac Shpantzer, Aviv Salamon, Arkady Kaplan, Pak Shing Cho, Jacob Khurgin, Yaakov Achiam, Arthur Greenblatt, Geofrey Harston
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Patent number: 7715720Abstract: An optical device is provided with first and second inputs. A first coupler coupled is coupled to the first input and produces at least a first and second output. A second coupler is coupled to the second input and produces at least a first and second output. A third coupler is coupled to the first output of the first coupler and to the first output of the second coupler. A fourth coupler is coupled to the second output of the first coupler and to the second output of the second coupler. First and second crossing waveguides are provided with an angle selected to minimize crosstalk and losses between the first and second cross waveguides. The first crossing waveguide connects one of the first or second outputs from the first coupler with an input of the fourth coupler. The second crossing waveguide connects one of the first or second outputs from the second coupler with an input of the third coupler. A first phase shifter is coupled to the first and second waveguides.Type: GrantFiled: April 3, 2007Date of Patent: May 11, 2010Assignee: CeLight, Inc.Inventors: Isaac Shpantzer, Aviv Salamon, Pak Shing Cho
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Publication number: 20090269083Abstract: An optical beam combiner is provided, which allows efficient collection of light for various applications: non-line of sight and free-space optical communications, remote sensing, optical imaging and others. A multitude of transverse scattered optical beam portions is captured by the multi-aperture array positioned perpendicular to the beam projection direction. These beam portions are combined first into a single optical waveguide with modulating the beam portions phase and coupling ratio of directional couplers in the optical beam combiner tuned to maximize the final output power. A portion of the output beam is used for the power detection and forming a feedback signal for the phases and coupling ratios adjustment. The data is recovered from the received optical beam using coherent detection.Type: ApplicationFiled: February 25, 2009Publication date: October 29, 2009Inventors: Pak Shing Cho, Jacob Khurgin, Isaac Shpantzer
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Publication number: 20090236528Abstract: A photo-thermal, interferometric spectroscopy system is disclosed that provides information about a chemical, such as explosives and the like, at a remote location. It may be used for solid residue detection on a surface. The system includes a novel light detector system with a matrix of optical elements focusing portions of a received light beam on input waveguides of an optical combiner. The combiner adjusts the phases of the received beam portions and combines them together to maximize the intensity of an output beam. The output beam is detected by a detector, and information about at least one of, absorption spectrum and concentration of the chemical is recovered. In the preferred embodiment the detector is a coherent detector based on 90-degrees optical hybrid.Type: ApplicationFiled: January 29, 2009Publication date: September 24, 2009Inventors: Isaac Shpantzer, Jacob Khurgin, Arkady Kaplan, Pak Shing Cho, Yaakov Achiam
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Publication number: 20090220246Abstract: A device for phase distortion compensation across an optical beam is provided. The device is a part of an optical receiver, which can be used in free space optical communications, remote sensing, optical imaging and others. 2M inputs of the combiner interfere with each other via a system of tunable coupled waveguides. The phases in interleaved waveguides of the combiner are adjusted to maximize the resulting output signal. The combiner may be used for coherent communication in combination with a balanced 90° hybrid. Integrated solutions for the proposed device are provided.Type: ApplicationFiled: December 9, 2008Publication date: September 3, 2009Inventors: Jacob Khurgin, Isaac Shpantzer, Arkady Kaplan, Pak Shing Cho
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Publication number: 20090214224Abstract: A system for high fidelity analog RF photonic communications is disclosed wherein linear phase modulation and linear coherent demodulation is included. A single optical beam with a phase-modulated signal optical carrier combined with an orthogonally polarized reference unmodulated optical carrier is transmitted simultaneously. At the receiver, the polarization of the reference carrier is transform to match that of the signal followed by coherent detection. An in-phase and quadrature-phase component of the homodyne signal is generated where they are digitized and processed to recover the original RF signal.Type: ApplicationFiled: May 4, 2009Publication date: August 27, 2009Inventors: Pak Shing Cho, Yaakov Achiam
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Publication number: 20090185811Abstract: An optical beam combiner is provided, which allows efficient collection of light for various applications: non-line of sight and free space optical communications, remote sensing, optical imaging and others. A multitude of optical beam portions is captured by a space diversity receiver that includes an optical beam combiner, which has a tree-like topology with interconnected waveguides, electro-optic phase shifters, and directional couplers. For each of the beam portions the phase of the phase shifter and the coupling ratio of coupler in the optical beam combiner are tuned sequentially to maximize the final output power in the final optical waveguide. A portion of the final output beam is used for the power detection and forming a feedback signal for the phases and coupling ratios adjustment. The data or information is recovered from the received final optical beam using coherent detection.Type: ApplicationFiled: February 20, 2009Publication date: July 23, 2009Inventors: Pak Shing Cho, Jacob Khurgin, Isaac Shpantzer
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Publication number: 20090169221Abstract: An optical beam combiner is provided, which allows efficient collection of light for various applications: non-line of sight and free space optical communications, remote sensing, optical imaging and others. A multitude of transverse scattered optical beam portions is captured by the multi-aperture array positioned perpendicular to the beam projection direction. These beam portions are combined first into a single optical waveguide with minimal loss of power. This is achieved by modulating the beam portions phase and coupling ratio of couplers in the optical beam combiner tuned to maximize the final output power. The data is recovered from the received optical beam using coherent detection.Type: ApplicationFiled: February 13, 2009Publication date: July 2, 2009Inventors: Pak Shing Cho, Isaac Shpantzer, Jacob Khurgin
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Publication number: 20090142051Abstract: An optical device is provided with first and second inputs. A first coupler coupled is coupled to the first input and produces at least a first and second output. A second coupler is coupled to the second input and produces at least a first and second output. A third coupler is coupled to the first output of the first coupler and to the first output of the second coupler. A fourth coupler is coupled to the second output of the first coupler and to the second output of the second coupler. First and second crossing waveguides are provided with an angle selected to minimize crosstalk and losses between the first and second cross waveguides. The first crossing waveguide connects one of the first or second outputs from the first coupler with an input of the fourth coupler. The second crossing waveguide connects one of the first or second outputs from the second coupler with an input of the third coupler. A first phase shifter is coupled to the first and second waveguides.Type: ApplicationFiled: November 12, 2007Publication date: June 4, 2009Inventors: Isaac Shpantzer, Aviv Salamon, Arkady Kaplan, Pak Shing Cho, Jacob Khurgin, Yaakov Achiam, Arthur Greenblatt, Geofrey Harston