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: 7512338Abstract: One embodiment of the invention relates to producing optical pulses for use on a transmission link. A light source is configured to produce an optical signal. A pulse generator is coupled to the light source. The pulse generator is configured to receive, for a first channel, the optical signal and a clock signal. The pulse generator is also configured to modify the optical signal based on the clock signal to produce an optical pulse having a predetermined pulse shape. The clock signal is associated with the predetermined pulse shape. The predetermined pulse shape being based on a transmission characteristic of the transmission link.Type: GrantFiled: August 11, 2006Date of Patent: March 31, 2009Assignee: CeLight, Inc.Inventors: Isaac Shpantzer, Israel Smilanski, Jacob B. Khurgin, Vladimir Grigoryan, Pak Shing Cho, Nadejda Reingand, Guy Levy-Yurista, Guoliang Li
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Patent number: 7483600Abstract: The present invention provides an integrated device and a method of its fabrication and use. Two parts of the device each having an electronic circuit are aligned adjacent to each other with an accuracy of at least 1 micron. An alignment system includes two parts: a first part integrated with the first electronic circuit of the integrated device on the first substrate and a second part integrated with the second electronic circuit of the integrated device on the second substrate. The second part of alignment system includes at least one photodiode. The maximal value of the photodiode current indicates the best alignment of two parts of the integrated device. In one embodiment the integrated device is a coherent optical detector for high speed optical communications and chemical sensing. In another embodiment the integrated optical device is a coherent optical detector operating in two polarization states of light.Type: GrantFiled: February 7, 2007Date of Patent: January 27, 2009Assignee: CeLight, Inc.Inventors: Yaakov Achiam, Isaac Shpantzer, Arthur Greenblatt, Geoffrey Harston, Arkady Kaplan, Pak Shing Cho
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Publication number: 20080175600Abstract: One embodiment of the invention relates to producing optical pulses for use on a transmission link. A light source is configured to produce an optical signal. A pulse generator is coupled to the light source. The pulse generator is configured to receive, for a first channel, the optical signal and a clock signal. The pulse generator is also configured to modify the optical signal based on the clock signal to produce an optical pulse having a predetermined pulse shape. The clock signal is associated with the predetermined pulse shape.Type: ApplicationFiled: August 11, 2006Publication date: July 24, 2008Inventors: Isaac Shpantzer, Israel Smilanski, Jacob B. Khurgin, Vladimir Grigoryan, Pak Shing Cho, Nadejda Reingand, Guy Levy-Yurista, Guoliang Li
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Patent number: 7397979Abstract: 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: December 14, 2006Date of Patent: July 8, 2008Assignee: CeLight, Inc.Inventors: Isaac Shpantzer, Arkady Kaplan, Aviv Salamon, Yaakov Achiam, Jacob B. Khurgin, Michael Tseytlin, Pak Shing Cho, Arthur Greenblatt, Christopher Kerr, Geoffrey Harston
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Patent number: 7391969Abstract: One embodiment of the invention relates to producing optical pulses for use on a transmission link. A light source is configured to produce an optical signal. A pulse generator is coupled to the light source. The pulse generator is configured to receive, for a first channel, the optical signal and a clock signal. The pulse generator is also configured to modify the optical signal based on the clock signal to produce an optical pulse having a predetermined pulse shape. The clock signal is associated with the predetermined pulse shape. The predetermined pulse shape being based on a transmission characteristic of the transmission link.Type: GrantFiled: December 27, 2006Date of Patent: June 24, 2008Assignee: CeLight, Inc.Inventors: Isaac Shpantzer, Israel Smilanski, Jacob B. Khurgin, Vladimir Grigoryan, Pak Shing Cho, Nadejda Reingand, Guy Levy-Yurista, Guoliang Li
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Patent number: 7327913Abstract: 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: September 22, 2003Date of Patent: February 5, 2008Assignee: Celight, Inc.Inventors: Isaac Shpantzer, Arkady Kaplan, Aviv Salamon, Yaakov Achiam, Jacob B. Khurgin, Michael Tseytlin, Pak Shing Cho, Arthur Greenblatt, Christopher Kerr, Geoffrey Harston
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Patent number: 7315697Abstract: A multiple wavelength light source generates an output signal having a comb of accurately spaced apart frequencies with variable free spectral range in the C-band of optical fiber communication. The light source employs an electro-optical modulator (EOM) driven by a signal generator which modulates with EOM with multiple modulation frequencies to widen the output spectrum of signal. The EOM has a crystal provided with a waveguide. The waveguide may be doped with a rare-earth metal to impart gain properties to equalize the intensities of the comb. In one preferred embodiment, Er, Yt or other doping elements provide the gain property to waveguides. The crystal is also provided with periodically poled structure, and this may be engineered so as to form domains of unequal widths to improve the efficiency of modulation. The output signal from the light source may be split and presented to a bank of filters to create a multiple signals, each signal having one of the spaced apart frequencies.Type: GrantFiled: June 18, 2002Date of Patent: January 1, 2008Assignee: CeLight, Inc.Inventors: Israel Smilanski, Isaac Shpantzer, Jacob B. Khurgin, Nadejda Reingand, Pak Shing Cho, Yaakov Achiam
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Patent number: 7277178Abstract: A photo-thermal, interferometric spectroscopy system is disclosed that provides information about a chemical at a remote location. A first light source assembly is included that emits a first beam. The first beam has one or more wavelengths that interact with the chemical and change a refractive index of the chemical. A second light source produces a second beam. The second beam interacts with the chemical resulting in a third beam with a phase change that corresponds with the change of the refractive index of the chemical. A detector system is positioned remote from the chemical to receive at least a portion of the third beam. The detector system provides information on a phase change in the third beam relative to the second beam that is indicative of at least one of, absorption spectrum and concentration of the chemical.Type: GrantFiled: January 13, 2005Date of Patent: October 2, 2007Assignee: Celight, Inc.Inventors: Isaac Shpantzer, Jacob B. Khurgin, Pak Shing Cho, Yaakov Achiam
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Patent number: 7272271Abstract: An optical device includes, a first Mach-Zehnder modulator that produces a first output, and a second Mach-Zehnder modulator which produces a second output. A splitter couples the first and second Mach-Zehnder modulators. A combiner combines the first and second outputs. A phase shifter is coupled to the first and second Mach-Zehnder modulators. The first Mach-Zehnder modulator, second Mach-Zehnder modulator, splitter, combiner and the phase shifter are each formed as part of a single chip made of electro-optical material. Such two similar optical device integrated together with polarization combiner provide a two-polarization performance.Type: GrantFiled: July 2, 2003Date of Patent: September 18, 2007Assignee: Celight, Inc.Inventors: Arkady Kaplan, Yaakov Achiam, Arthur Greenblatt, Isaac Shpantzer, Pak Shing Cho, Michael Tseytlin, Aviv Salamon
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Patent number: 7266307Abstract: One embodiment of the invention relates to producing optical pulses for use on a transmission link. A light source is configured to produce an optical signal. A pulse generator is coupled to the light source. The pulse generator is configured to receive, for a first channel, the optical signal and a clock signal. The pulse generator is also configured to modify the optical signal based on the clock signal to produce an optical pulse having a predetermined pulse shape. The clock signal is associated with the predetermined pulse shape.Type: GrantFiled: August 9, 2002Date of Patent: September 4, 2007Inventors: Isaac Shpantzer, Israel Smilanski, Jacob B. Khurgin, Vladimir Grigoryan, Pak Shing Cho, Nadejda Reingand, Guy Levy-Yurista, Guoliang Li
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Patent number: 7242481Abstract: An optical system provides information about tangential vibration components of a surface at remote location. The optical system includes a light source assembly that emits first and second beams, each having one or more wavelengths and one or two polarizations. The first and second beams are directed to the interrogated surface. A detector system is positioned to detect a third beam formed by at least a portion of the first and second beams being reflected from the interrogated surface. The first, second and third beams having incident and reflection angles relative to the interrogated surface that do not lay in a same plane. The detector system positioned remotely from the interrogated surface, and providing information on a phase change in the third beam relative to the first and second beam. The phase change is indicative of at least one surface vibration vector component of the interrogated surface. The detector system is a 90 degree optical hybrid balanced detector with four photodiodes.Type: GrantFiled: February 9, 2005Date of Patent: July 10, 2007Assignee: Celight, Inc.Inventors: Isaac Shpantzer, Aviv Salamon, Pak Shing Cho
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Publication number: 20070133918Abstract: 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: February 27, 2007Publication date: June 14, 2007Inventors: Pak Shing Cho, Jacob Khurgin, Isaac Shpantzer
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Patent number: 7224906Abstract: The present invention relates to a method for transmitting data. An optical pulse stream comprising a plurality of return-to-zero optical pulses is prepared by modulating a phase of light output by an optical source to thereby encode data from a data source. The light of the optical pulse stream has a wavelength. The optical pulse stream is transmitted along an optical fiber of an optical network. Optical pulse streams of the invention enhance transmission performance at least in part by reducing noise at the receiver caused by fiber non-linearities.Type: GrantFiled: February 28, 2002Date of Patent: May 29, 2007Assignee: CeLight, Inc.Inventors: Pak Shing Cho, Nadejda Reingand, Vladimir Grigoryan, Alper Demir, Aviv Salamon, Isaac Shpantzer
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Patent number: 7167651Abstract: A system for optical communication forms a family of orthogonal optical codes modulated by a data stream. The orthogonal codes are formed by creating a stream of evenly spaced-apart pulses using a pulse spreader circuit and modulating the pulses in amplitude and/or phase to form a family of orthogonal optical code words, each representing a symbol. A spreader calibration circuit is used to ensure accurate timing and modulation. Each code word is further modulated by a predetermined number of data bits. The data modulation scheme splits a code word into H and V components, and further processes the components prior to modulation with data, followed by recombining with a polarization beam combiner. The data-modulated code word is then sent, along with others to receiver. The received signal is detected and demodulated with the help of a symbol synchronization unit which establishes the beginning and end of the code words.Type: GrantFiled: September 26, 2001Date of Patent: January 23, 2007Assignee: CeLight, Inc.Inventors: Isaac Shpantzer, Michael Tseytlin, Yaakov Achiam, Aviv Salamon, Israel Smilanski, Olga Ritterbush, Pak Shing Cho, Li Guoliang, Jacob Khurgin, Yehouda Meiman, Alper Demir, Peter Feldman, Peter Kinget, Nagendra Krishnapura, Jaijeet Roychowdhury, Joseph Schwarzwalder, Charles Sciabarra
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Method and system for optical time division multiplexed fiber communications with coherent detection
Patent number: 7110677Abstract: The present invention relates to a receiver for receiving a time division multiplexed (TDM) optical signal, which is formed of a plurality of interleaved optical pulse streams. Each optical pulse stream includes a plurality of optical pulses. The receiver includes a detector for detecting at least a first optical pulse stream of the optical signal and an optical hybrid for coherently mixing the first optical pulse stream with a reference pulse stream. The first optical pulse stream and the reference pulse stream impinge simultaneously upon the detector.Type: GrantFiled: September 26, 2001Date of Patent: September 19, 2006Assignee: CeLight, Inc.Inventors: Nadejda Reingand, Jacob Khurgin, Pak Shing Cho -
Publication number: 20040096143Abstract: 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: September 22, 2003Publication date: May 20, 2004Applicant: CeLight, Inc.Inventors: Isaac Shpantzer, Arkady Kaplan, Aviv Salamon, Yaakov Achiam, Jacob B. Khurgin, Michael Tseytlin, Pak Shing Cho, Arthur Greenblatt, Christopher Kerr, Geoffrey Harston
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Patent number: 6701049Abstract: All-optical timing extraction and optical clock recovery for high-speed return-to-zero binary optical data streams using the timing difference between clock and data counter-propagating optical pulses in a non-linear optical waveguide where the first pulse to arrive at the non-linear optical waveguide partially saturates the transmission properties of the waveguide resulting in a change of the transmission properties seen by the lagging pulse. A balanced photo-detector makes delay-dependent comparisons of the clock and data pulses' peak power and generates an error signal used in a phase-locked loop configuration to synchronize the clock to the data stream.Type: GrantFiled: March 21, 2003Date of Patent: March 2, 2004Assignee: The United States of America as represented by The National Security AgencyInventors: Ehab Awad, Julius Goldhar, Pak Shing Cho, Christopher Richardson, Norman Moulton
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Publication number: 20040028418Abstract: An optical device includes, a first Mach-Zehnder modulator that produces a first output, and a second Mach-Zehnder modulator which produces a second output. A splitter couples the first and second Mach-Zehnder modulators. A combiner combines the first and second outputs. A phase shifter is coupled to the first and second Mach-Zehnder modulators. The first Mach-Zehnder modulator, second Mach-Zehnder modulator, splitter, combiner and the phase shifter are each formed as part of a single chip made of electro-optical material. Such two similar optical device integrated together with polarization combiner provide a two-polarization performance.Type: ApplicationFiled: July 2, 2003Publication date: February 12, 2004Inventors: Arkady Kaplan, Yaakov Achiam, Arthur Greenblatt, Isaac Shpantzer, Pak Shing Cho, Michael Tseytlin, Aviv Salamon
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Patent number: 6671425Abstract: The present invention relates to an integrated light source having first and second optical waveguides defining a first optical coupling region for coupling light therebetween. At least one of the optical waveguides includes a gain medium configured to emit light upon irradiation. The light source also includes a first acoustic wave source to subject the first optical coupling region to acoustic waves having a longitudinal frequency &ohgr;AC1, whereby a frequency of light propagating along one of the first and second waveguides differs from a frequency of light propagating along the other waveguide by an amount by an amount &ohgr;AC1.Type: GrantFiled: June 18, 2002Date of Patent: December 30, 2003Assignee: CeLightInventors: Jacob B. Khurgin, Nadejda Reingand, Isaac Shpantzer, Israel Smilanski, Pak Shing Cho
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Publication number: 20030231817Abstract: The present invention relates to an integrated light source having first and second optical waveguides defining a first optical coupling region for coupling light therebetween. At least one of the optical waveguides includes a gain medium configured to emit light upon irradiation. The light source also includes a first acoustic wave source to subject the first optical coupling region to acoustic waves having a longitudinal frequency &ohgr;AC1, whereby a frequency of light propagating along one of the first and second waveguides differs from a frequency of light propagating along the other waveguide by an amount &ohgr;AC1.Type: ApplicationFiled: June 18, 2002Publication date: December 18, 2003Inventors: Jacob B. Khurgin, Nadejda Reingand, Isaac Shpantzer, Israel Smilanski, Pak Shing Cho