Using Optical Phase Conjugation Patents (Class 398/150)
  • Patent number: 10985900
    Abstract: Managing clock-data recovery for a modulated signal from a communication channel comprises: receiving the modulated signal and providing one or more analog signals, providing one or more digital input streams from samples of the analog signals, and processing the digital input streams to provide decoded digital data. The processing comprises: determining the decoded digital data based on information modulated over a plurality of frequency elements associated with the modulated signal, based at least in part on transforms of the digital input streams; a clock signal based on clock recovery from the digital input streams; and determining a clock phase error estimate associated with the determined clock signal based at least in part on a sum that includes different weights multiplied by different respective summands corresponding to different sets of frequency elements.
    Type: Grant
    Filed: March 3, 2020
    Date of Patent: April 20, 2021
    Assignee: Ciena Corporation
    Inventors: Ahmad Abdo, Shahab Oveis Gharan, James Harley, Sadok Aouini, Timothy James Creasy, Naim Ben-Hamida
  • Patent number: 10536153
    Abstract: There is provided a signal generator and associated method for generating a source signal. The signal generator includes a frequency generator for providing an oscillating signal, a phase comparator, a first phase modulator, a second phase modulator and a phase shifter. The phase comparator is adapted to compare a phase signal with a feedback signal and to generate an error signal to control the phase of the oscillating signal. The first and second phase modulators are adapted to provide a first phase control word and a second phase control word respectively. The phase shifter is adapted to modulate the oscillating signal based on the second phase control word to generate the source signal. The source signal comprises the feedback signal.
    Type: Grant
    Filed: June 28, 2019
    Date of Patent: January 14, 2020
    Assignee: Dialog Semiconductor B.V.
    Inventor: Duan Zhao
  • Patent number: 9099835
    Abstract: Fiber optic amplification in a spectrum of infrared electromagnetic radiation is achieved by creating a chalcogenide photonic crystal fiber (PCF) structure having a radially varying pitch. A chalcogenide PCF system can be tuned during fabrication of the chalcogenide PCF structure, by controlling, the size of the core, the size of the cladding, and the hole size to pitch ratio of the chalcogenide PCF structure and tuned during exercising of the chalcogenide PCF system with pump laser and signal waves, by changing the wavelength of either the pump laser wave or the signal wave, maximization of nonlinear conversion of the chalcogenide PCF, efficient parametric conversion with low peak power pulses of continuous wave laser sources, and minimization of power penalties and minimization of the need for amplification and regeneration of pulse transmissions over the length of the fiber, based on a dispersion factor.
    Type: Grant
    Filed: July 19, 2009
    Date of Patent: August 4, 2015
    Assignee: The United States of America, as represented by the Secretary of the Navy
    Inventors: Leslie Brandon Shaw, Ishwar Dayal Aggarwal, Jasbinder Singh Sanghera, Daniel Joseph Gibson, Frederic Hau Kung
  • Patent number: 8971718
    Abstract: A clock and data recovery (CDR) circuit, a method of recovering a clock and data from a received raw data stream and a BI-PON optical network transceiver (ONT) receiver front-end incorporating the CDR circuit. In one embodiment, the CDR circuit includes: (1) a line rate CDR circuit having a voltage controlled oscillator, the line rate CDR circuit configured to recover a raw data stream at a receiving line rate, (2) a fixed-rate down-sampler coupled to the line rate CDR circuit and configured to down-sample the raw data stream based on a fixed-rate and (3) a variable-rate down-sampler coupled to the fixed-rate down-sampler and configured further to down-sample the raw data sample based on a variable-rate.
    Type: Grant
    Filed: June 1, 2012
    Date of Patent: March 3, 2015
    Assignee: Alcatel Lucent
    Inventors: Hungkei Chow, Dusan Suvakovic, Christophe Van Praet, Guy Torfs, Xin Yin, Zhisheng Li
  • Patent number: 8897650
    Abstract: A sending/receiving system includes first and second sending/receiving apparatuses. The first sending/receiving apparatus includes a first sending section that sends link establishment information via first transmission channels. The second sending/receiving apparatus includes a second sending section, link establishing sections, and a controller. The second sending section sends link establishment information to the first sending/receiving apparatus via a second transmission channel. Each of the link establishing sections is provided for a corresponding one of the first transmission channels and establishes a link in the corresponding first transmission channel on the basis of the link establishment information.
    Type: Grant
    Filed: August 20, 2012
    Date of Patent: November 25, 2014
    Assignee: Fuji Xerox Co., Ltd.
    Inventor: Hirokazu Tsubota
  • Patent number: 8879920
    Abstract: The present wavelength multiplexed optical system includes a multimode optical fiber that transmits wavelength multiplexed optical signals and a plurality of multimode modal dispersion compensation optical fibers. Each modal dispersion compensation optical fiber can transmit one of the multiplex wavelengths, and each modal dispersion compensation optical fiber has an optimized index profile such that the modal dispersion for the transmitted wavelength is approximately inversely equal to the modal dispersion induced in the multimode optical fiber. The wavelength multiplexed optical system facilitates an increased bitrate without reducing bandwidth.
    Type: Grant
    Filed: June 23, 2009
    Date of Patent: November 4, 2014
    Assignee: Draka Comteq, B.V.
    Inventors: Yves Lumineau, Denis Molin, Asghar Gholami
  • Patent number: 8849126
    Abstract: Exemplary embodiments include a method and systems for impairment compensation in a communication system. The systems can include an electronic phase conjugation system that receives an incoming optical signal from a first section of a fiber optic link, converts the incoming optical signal to an in-phase electric signal and a quadrature electrical signal, and generates a phase conjugated outgoing optical signal from the in-phase and quadrature electrical signals. The phase conjugated outgoing optical signal compensates for impairment of the fiber in the communication system.
    Type: Grant
    Filed: January 10, 2011
    Date of Patent: September 30, 2014
    Assignee: AT&T Intellectual Property I, L.P.
    Inventors: Xiang Zhou, Guifang Li, Eduardo F. Mateo
  • Patent number: 8818206
    Abstract: The present disclosure provides electrical domain suppression of linear crosstalk in optical communication systems using single-carrier implementations. This electrical domain suppression applies spectral shaping in the electronic radio frequency (RF) domain. Advantageously, spectral shaping in the electronic RF domain transfers system complexity from the bulk optical domain into the highly integrated CMOS (or equivalent) domain. The spectral shaping can include electronic circuitry including an electrical filtering block and a signal linearization block prior to optical modulation. The electrical filtering block suppresses coherent interference terms and can include an RF-domain low pass filter. The signal linearization block linearizes modulator response to compensate spectral regrowth due to nonlinear mixing in the modulator.
    Type: Grant
    Filed: June 24, 2009
    Date of Patent: August 26, 2014
    Assignee: Ciena Corporation
    Inventor: Michael Y. Frankel
  • Patent number: 8818193
    Abstract: An embodiment of the invention includes a tunable optical dispersion compensator (TODC) comprising a first beam displacer on an optical path, wherein the first beam displacer separates an optical signal into a first beam and a second beam, and one or more polarizing beam splitters on the optical path, wherein the one or more polarizing beam splitters keep the first beam and the second beam on the optical path. The TODC also comprises one or more etalons on the optical path, wherein the one or more etalons are tunable to introduce a group delay in the first beam and the second beam, and a reflecting mirror on the optical path, wherein the reflecting mirror returns the optical signal back along the optical path. The TODC further comprises a second beam displacer, wherein the second beam displacer combines the first beam and the second beam into an output optical signal.
    Type: Grant
    Filed: September 29, 2009
    Date of Patent: August 26, 2014
    Assignee: Finisar Corporation
    Inventors: Fan Chen, Yongkang Hu, Zhenli Wen, Dongshen Han, Fahua Lan, Kevin Dapeng Zhang
  • Patent number: 8798477
    Abstract: The present invention relates to chromatic dispersion monitor and method, chromatic dispersion compensator. The chromatic dispersion monitor is used for estimating a chromatic dispersion in accordance with a chromatic dispersion correlation amount sequence, comprising: a phase differential unit, for obtaining a phase difference sequence by performing a phase differential calculation in accordance with the chromatic dispersion correlation amount sequence; a phase difference differential unit, for obtaining a phase difference differential sequence by performing a phase difference differential operation; and a chromatic dispersion estimating unit, for estimating the chromatic dispersion in accordance with the phase difference differential sequence obtained by the phase difference differential unit.
    Type: Grant
    Filed: November 20, 2009
    Date of Patent: August 5, 2014
    Assignee: Fujitsu Limited
    Inventors: Ling Liu, Zhenning Tao, Takahito Tanimura
  • Patent number: 8542997
    Abstract: The invention relates to a passive optical network comprising an optical exchange linked by at least one optical fiber to at least one line termination device of said network, able to transmit a downlink optical signal phase-modulated in NRZ-DPSK format and to receive an uplink optical signal. According to the invention, said line termination device comprises means of converting the transmitted downlink optical signal phase-modulated in NRZ-DPSK format into an optical data signal amplitude-modulated in duobinary modulation format and means of generating an uplink optical signal phase-modulated in NRZ-DPSK format from the downlink optical signal phase-modulated in NRZ-DPSK format. The optical exchange is able to convert the uplink optical signal phase-modulated in NRZ-DPSK format into an optical data signal amplitude-modulated in duobinary modulation format.
    Type: Grant
    Filed: June 18, 2008
    Date of Patent: September 24, 2013
    Assignee: France Telecom
    Inventors: Erwan Pincemin, Naveena Genay
  • Patent number: 8457500
    Abstract: An all-optical modulation format converter for converting optical data signals modulated in an on-off-keying (OOK) format to a phase-shift-keying (PSK) format. The OOK-to-PSK converter can be coupled to a delay-line interferometer to provide an all-optical wavelength converter for differential PSK (DPSK). The OOK-to-PSK converter can also be used in all-optical implementations of various functions, including, for example, exclusive-OR (XOR/NXOR) and OR logic, shift registers, and pseudo-random binary sequence (PRBS) generators. Several variants of all-optical devices are described.
    Type: Grant
    Filed: August 23, 2010
    Date of Patent: June 4, 2013
    Assignee: Alcatel Lucent
    Inventor: Inuk Kang
  • Patent number: 8396372
    Abstract: An apparatus includes a non-solitonic all-optical communication path having serially connected first and second segments. The first segment end-couples to a lumped optical transmitter. The second segment end-couples to a lumped optical receiver. Each segment has a series of spans of transmission optical fibers. The all-optical communication path has an optical phase conjugator that optically end-couples the first segment to the second segment. The optical phase conjugator is positioned away from the path's midpoint.
    Type: Grant
    Filed: September 2, 2004
    Date of Patent: March 12, 2013
    Assignee: Alcatel Lucent
    Inventors: Aref Chowdhury, Rene′-Jean Essiambre, Gregory Raybon
  • Patent number: 8385747
    Abstract: A signal equalizer for compensating impairments of an optical signal received through a link of a high speed optical communications network. At least one set of compensation vectors are computed for compensating at least two distinct types of impairments. A frequency domain processor is coupled to receive respective raw multi-bit in-phase (I) and quadrature (Q) sample streams of each received polarization of the optical signal. The frequency domain processor operates to digitally process the multi-bit sample streams, using the compensation vectors, to generate multi-bit estimates of symbols modulated onto each transmitted polarization of the optical signal. The frequency domain processor exhibits respective different responses to each one of the at least two distinct types of impairments.
    Type: Grant
    Filed: June 15, 2011
    Date of Patent: February 26, 2013
    Assignee: Ciena Corporation
    Inventors: Kim B. Roberts, Han Sun
  • Patent number: 8326160
    Abstract: A dispersion compensation device includes: an optical branching unit to branch an optical signal to be received; a first dispersion compensator to perform dispersion compensation on one part of the optical signal branched by the optical branching unit with a variable compensation amount; a second dispersion compensator to perform dispersion compensation on another part of the optical signal branched by the optical branching unit; a monitoring unit to monitor the communication quality of an output optical signal of the second dispersion compensator; and a controlling unit to determine the direction of variation in chromatic dispersion of the optical signal based on the direction of variation in communication quality monitored by the monitoring unit and control the compensation amount of the first dispersion compensator based on the result of the determination.
    Type: Grant
    Filed: November 22, 2010
    Date of Patent: December 4, 2012
    Assignee: Fujitsu Limited
    Inventors: Makoto Murakami, Toshihiro Ohtani
  • Patent number: 8280258
    Abstract: The present disclosure provides optical communication systems and methods that utilize, on top or in place of the conventional framework: (1) optical amplifiers that are provided with extended bandwidth coverage, such as Extended Band Erbium-Doped Fiber Amplifiers (EDFAs), combination of Raman amplifiers and EDFAs, Split-Band C+L EDFAs, etc.
    Type: Grant
    Filed: June 30, 2009
    Date of Patent: October 2, 2012
    Assignee: Ciena Corporation
    Inventor: Michael Y. Frankel
  • Patent number: 8244141
    Abstract: An apparatus for generating a dispersion compensation signal includes a splitting module for splitting a data signal to be transmitted into N channels of data signals; N pre-processing modules for adjusting in frequency domain the phases and amplitudes of the N channels of data signals and outputting N channels of pre-warped electrical signals; an optical carrier generating module for generating N channels of coherent optical carriers; N electro-optic modulators for modulating the N channels of coherent optical carriers based on the N channels of pre-warped electrical signals and generating N channels of pre-warped optical signals; an optical coupling module for coupling the N channels of pre-warped optical signals into a dispersion compensation optical signal. By pre-processing the data signals, the present disclosure may allow the use of existing devices to generate a dispersion compensation signal so that the bandwidth requirement set by prior art on the electrical device is reduced.
    Type: Grant
    Filed: September 22, 2009
    Date of Patent: August 14, 2012
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Wei Fu, Zhihui Tao, Yue Liu, Jia Jia
  • Patent number: 8078060
    Abstract: Femtosecond pump/probe experiments using short X-Ray and optical pulses require precise synchronization between 100 meter-10 km separated lasers in a various experiments. For stabilization in the hundred femtosecond range a CW laser is amplitude modulated at 1-10 GHz, the signal retroreflected from the far end, and the relative phase used to correct the transit time with various implementations. For the sub-10 fsec range the laser frequency itself is upshifted 55 MHz with an acousto-optical modulator, retroreflected, upshifted again and phase compared at the sending end to a 110 MHz reference. Initial experiments indicate less than 1 fsec timing jitter. To lock lasers in the sub-10 fs range two single-frequency lasers separated by several teraHertz will be lock to a master modelocked fiber laser, transmit the two frequencies over fiber, and lock two comb lines of a slave laser to these frequencies, thus synchronizing the two modelocked laser envelopes.
    Type: Grant
    Filed: April 4, 2007
    Date of Patent: December 13, 2011
    Assignee: The Regents of The University of California
    Inventors: Russell B. Wilcox, Ronald Holzwarth
  • Patent number: 8073336
    Abstract: Entanglement-based QKD systems and methods with active phase tracking and stabilization are disclosed wherein pairs of coherent photons at a first wavelength are generated. Second harmonic generation and spontaneous parametric downconversion are used to generate from the pairs of coherent photons entangled pairs of photons having the first wavelength. Relative phase delays of the entangled photons are tracked using reference optical signals. Classical detectors detect the reference signals while single-photon detectors and a control unit generate a phase-correction signal that maintains the relative phases of phase-delay loops via adjustable phase-delay elements.
    Type: Grant
    Filed: January 31, 2007
    Date of Patent: December 6, 2011
    Assignee: MagiQ Technologies, Inc.
    Inventor: Alexei Trifonov
  • Patent number: 8005368
    Abstract: A signal equalizer for compensating impairments of an optical signal received through a link of a high speed optical communications network. At least one set of compensation vectors are computed for compensating at least two distinct types of impairments. A frequency domain processor is coupled to receive respective raw multi-bit in-phase (I) and quadrature (Q) sample streams of each received polarization of the optical signal. The frequency domain processor operates to digitally process the multi-bit sample streams, using the compensation vectors, to generate multi-bit estimates of symbols modulated onto each transmitted polarization of the optical signal. The frequency domain processor exhibits respective different responses to each one of the at least two distinct types of impairments.
    Type: Grant
    Filed: December 5, 2007
    Date of Patent: August 23, 2011
    Assignee: Ciena Corporation
    Inventors: Kim Roberts, Han Sun
  • Patent number: 7983566
    Abstract: A method and system for improving the performance of a differential-phase modulated optical communication system is disclosed. The system comprises a demodulator having a tunable element to adjust the free-spectral range (FSR) thereof, and a tunable phase shifter to adjust a frequency of a signal passing therethrough.
    Type: Grant
    Filed: February 12, 2008
    Date of Patent: July 19, 2011
    Assignee: AT&T Intellectual Property II, LLP
    Inventors: Xiang Zhou, Guodong Zhang
  • Patent number: 7873272
    Abstract: An optical pulse monitor (OPM) that determines an optical phase profile for a pulse train by (i) modulating the optical phase of pulses in the pulse train using a periodic waveform and (ii) generating a derivative of a spectrum of the resulting modulated signal with respect to the waveform's amplitude. In one embodiment, an OPM has a phase modulator that modulates the optical phase of pulses in a received pulse train using a periodic waveform supplied by a configurable drive circuit. The drive circuit temporally aligns the waveform with the pulse train to serially produce each of four selected temporal alignments. An optical signal analyzer measures a spectrum of the modulated signal generated by the modulator for each of these four temporal alignments and provides the four measured spectra to a processor. The processor uses the measured spectra to determine two spectrum derivatives with respect to the waveform's amplitude.
    Type: Grant
    Filed: November 13, 2006
    Date of Patent: January 18, 2011
    Assignee: Alcatel-Lucent USA Inc.
    Inventor: Inuk Kang
  • Patent number: 7831005
    Abstract: In a circuit suppressing jitters without a synchronizing clock signal and an increase of a circuit scale, input data is regenerated by a data regeneration circuit in a broadband, a predetermined signal pattern which generates phase deviations exceeding a predetermined value is detected from the data regenerated by the data regeneration circuit by a pattern detection circuit, a reverse phase deviation signal having reverse phase deviations of phase deviations corresponding to the predetermined signal pattern is generated by a reverse phase deviation generating circuit, and an output signal of the data regeneration circuit is canceled by a phase deviation correcting circuit with the reverse phase deviation signal.
    Type: Grant
    Filed: September 18, 2007
    Date of Patent: November 9, 2010
    Assignee: Fujitsu Limited
    Inventor: Naoki Kuwata
  • Patent number: 7796896
    Abstract: A secure optical communication scheme uses differential delay D in an unbalanced Mach-Zehender interferometer to provide two copies of the optical source signal at a remote phase modulator separated in time by D. As D is much bigger than the coherence time source, the two copies of the signal are effectively uncorrelated. Both signals are phase-modulated by the remote sender's data and returned to the unbalanced interferometer. The phase modulator will be converted into amplitude modulation by the action of the interferometer.
    Type: Grant
    Filed: September 29, 2004
    Date of Patent: September 14, 2010
    Assignee: British Telecommunications plc
    Inventors: Edmund S R Sikora, Peter Healey
  • Patent number: 7725037
    Abstract: A method and apparatus for switching at least one wavelength component of an optical signal beam from a first state to a second state. The phase characterizing the optical signal component is incremented by interaction with one or more escort beams in a non-linear medium thereby switching the state of the optical signal component on the basis of its incremented phase. Multiple escort beams may also be employed to switch different wavelength components of the signal. The method may be employed to achieve high speed, and substantially transparent, switching of phase, intensity or polarization of a signal.
    Type: Grant
    Filed: November 13, 2006
    Date of Patent: May 25, 2010
    Assignee: The Board of Trustees of the University of Illinois
    Inventors: Aaron Pace VanDevender, Paul G. Kwiat
  • Patent number: 7697802
    Abstract: This invention pertains to optical fiber transmission networks, and is particularly relevant to transmission of high volume of data and voice traffic among different locations. In particular, the improvement teaches improvements to an optical transport system to allow for efficient and flexible network evolution.
    Type: Grant
    Filed: June 6, 2008
    Date of Patent: April 13, 2010
    Inventor: Marvin R. Young
  • Patent number: 7660491
    Abstract: A cw-laser source transmits low-noise, narrow-linewidth optical power via an optical fiber to a bias-free electro-optic phase modulator at a remote site, where an antenna or an RF sensor is located. The RF electrical signal modulates the phase modulator at the remote site, converting an electrical signal into an optical signal. The phase-modulated optical signal is fed back via the optical fiber to an optical filter whose filter transfer characteristics can be tuned and reconfigured to cancel the intermodulation distortion terms, particularly the dominant 3rd order intermodulation, as well as the 2nd order. The filtered optical signal is converted to the RF signal at the photodetector. The optical filter is used to effectively “linearize” the signal at the receiver end, rather than at the modulator end.
    Type: Grant
    Filed: August 1, 2007
    Date of Patent: February 9, 2010
    Assignee: EOSpace, Inc.
    Inventor: Suwat Thaniyavarn
  • Patent number: 7590356
    Abstract: The present invention provides: (1) a compensator that compensates a wide range of amount of dispersion of light in a wide bandwidth band; and (2) a variable dispersion slope compensator applicable to the case where a transmission path suitable for a wavelength division multiplexing transmission system produces a wavelength dispersion slope.
    Type: Grant
    Filed: December 20, 2006
    Date of Patent: September 15, 2009
    Assignee: Hitachi Metals Ltd.
    Inventors: Toshiki Sugawara, Kazuhiko Hosomi, Satoshi Makio
  • Patent number: 7577328
    Abstract: An optical reflector, an optical multiplexer/demultiplexer device and an optical system which can allow more flexible arrangement of an optical filter thereof, and enhance performance of wavelength division multiplexing communication thereof are provided. An optical reflector according to the present invention comprises a first and second optical fiber 14, 16, each being connected to one side of an optical propagating region such as a rod lens 12 causing optical strength distributions depending on respective wavelengths of lights to be propagated in the optical propagating region; a mirror 18 disposed on the other side of the optical propagating region; and an optical filter 20 disposed between the first and second optical fibers 14, 16 and the mirror 18.
    Type: Grant
    Filed: May 15, 2007
    Date of Patent: August 18, 2009
    Assignee: Hitachi Chemical Company, Ltd.
    Inventors: Nobuo Miyadera, Rei Yamamoto
  • Patent number: 7558485
    Abstract: The desirable effects of an optical phase conjugator are accompanied by a frequency shift with reversal of the frequency order of channels in a multichannel optical communication system. Such effects are rectifiable by employing a sequence involving demultiplexing the multichannel signal, operating on the individual, demultiplexed channel with a corresponding optical phase conjugator or frequency shifter followed by multiplexing the signal. This sequence is combined with a complementary operation—optical phase conjugator to complement a frequency shifting sequence or frequency shifting to complement an optical phase conjugating sequence.
    Type: Grant
    Filed: May 20, 2003
    Date of Patent: July 7, 2009
    Assignee: Alcatel-Lucent USA Inc.
    Inventors: Aref Chowdhury, Rene′ -Jean Essiambre
  • Patent number: 7509054
    Abstract: Binary signals are converted at the transmission end into two optical signals which are combined into a polarization multiplex signal and are then transmitted. The transmitted polarization multiplex signal is divided at the receiving end into two polarized signal parts which are converted in a linear manner into orthogonal electrical components and are supplied to a multidimensional filter. Said multidimensional filter replaces a polarization controller, restores the signal values that correspond to the signals at the transmission end, and compensates signal distortions.
    Type: Grant
    Filed: August 13, 2003
    Date of Patent: March 24, 2009
    Assignee: Nokia Siemens Networks GmbH & Co KG
    Inventors: Stefano Calabro, Erich Gottwald, Nancy Hecker, Georg Sebald, Bernhard Spinnler
  • Patent number: 7379677
    Abstract: The wavelength converter comprises (1) an optical multiplexer for multiplexing an amplitude-modulated first light and reference light, which is continuous light having a wavelength different from the wavelength of the first light, (2) an optical fiber for propagating the multiplexed light therethrough to generate a third light by a non-linear optical phenomenon, and (3) an optical filter having a pass wavelength range set such that a pulse time width of the third light is 20% or more narrower than a pulse time width of the first light after the third light has passed through the optical filter, or (3?) an optical filter having a pass wavelength range set such that a cross point of an eye pattern of the third light is lower than a cross point of an eye pattern of the first light after the third light has passed through the optical filter.
    Type: Grant
    Filed: January 26, 2005
    Date of Patent: May 27, 2008
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Toshiaki Okuno
  • Patent number: 7324759
    Abstract: Method and apparatus for transmitting a light signal in an optical transmission system is described. In an example, an optical transmission link includes an input port and an output port. The optical transmission link is configured to propagate optical pulses from the input port to the output port. Information is encoded using phase relationships between adjacent ones of the optical pulses. A phase conjugator is disposed between the input port and the output port. The phase conjugator is positioned to reduce phase variance of the optical pulses at the output port.
    Type: Grant
    Filed: June 30, 2003
    Date of Patent: January 29, 2008
    Assignee: Lucent Technologies Inc.
    Inventors: Colin J. McKinstrie, Stojan Radic, Chongjin Xie
  • Patent number: 7310318
    Abstract: A optical communications network including at least one optical phase conjugator for compensating for non-linear effects. The optical communications network includes at least one dispersion compensation module before the optical phase conjugator and at least one dispersion compensation module after the optical phase conjugator. The dispersion compensation modules compensate for linear effects of the transmission path such as dispersion and dispersion slope. This allows the optical phase conjugator to be designed to compensate for non-linear effects such as self-phase modulation and cross-phase modulation. The separate compensation of linear and non-linear effects provides enhanced control of these effects.
    Type: Grant
    Filed: May 3, 2002
    Date of Patent: December 18, 2007
    Assignee: Ciena Corporation
    Inventors: Michael Y. Frankel, Harshad P. Sardesai
  • Patent number: 7302189
    Abstract: It is an object of the present invention to provide an optical component provided with a demultiplexing function capable of reducing an insertion loss and downsizing, and a wavelength dispersion compensator using such an optical component.
    Type: Grant
    Filed: March 2, 2004
    Date of Patent: November 27, 2007
    Assignee: Fujitsu Limited
    Inventor: Yuichi Kawahata
  • Patent number: 7206516
    Abstract: The invention pertains to optical fiber transmission systems, and is particularly relevant to transmission of large volumes of data over long distances at high rates. An improved apparatus and method for measuring dispersion in a fiber span is disclosed. In particular, the invention teaches a highly accurate technique for measuring the fiber dispersion at a single wavelength. Transmitter and receiver structure and data processing algorithms are disclosed. An improved apparatus and method for measuring dispersion in a fiber span. In particular, the invention teaches a highly accurate technique for measuring the fiber dispersion at a single wavelength. Transmitter and receiver structure and data processing algorithms are disclosed.
    Type: Grant
    Filed: April 30, 2003
    Date of Patent: April 17, 2007
    Assignee: Pivotal Decisions LLC
    Inventor: Michael H. Eiselt
  • Patent number: 7203423
    Abstract: Methods and systems for higher-order PMD compensation are implemented by developing an effective mathematical model and applying economical design techniques to the model. By assuming a constant precession rate for a narrow band of frequencies in an optical signal, a simplified model of a higher-order PMD compensator can be derived. The model can be used produce an economical compensator by making multiple uses of selected optical components.
    Type: Grant
    Filed: September 30, 2005
    Date of Patent: April 10, 2007
    Assignee: AT&T Corp.
    Inventors: Antonio Mecozzi, Jonathan A. Nagel, Mark Shtaif, Moshe Tur
  • Patent number: 7187868
    Abstract: A WDM system includes a transmission station, a receiving station, a first optical path and a second optical path. The first optical path includes a first section and a second section, the second section being capable of compensating at least partially the dispersion accumulated by a series of optical channels along the first section. The series of channels includes at least a first plurality of channels having an average dispersion of the same sign in the first optical path. The system also includes at least a first conversion device, capable of inverting the spectrum and modifying the wavelength of at least the first plurality of channels, to produce a second plurality of channels having an average chromatic dispersion of the same sign in the second optical path.
    Type: Grant
    Filed: July 29, 2002
    Date of Patent: March 6, 2007
    Assignee: Pirelli Cavi E Sistemi S.p.A.,
    Inventors: Fabrizio Carbone, Luciano Socci, Marco Romagnoli
  • Patent number: 7184665
    Abstract: A chromatic dispersion compensator in a single-pass and a double-pass version is disclosed. In a single-pass version, the compensator has a diffractive grating for spatially separating an input optical signal into spatially spaced frequency components and a MEMS array of separate phase shifters, each for imparting an independent phase shift to a channel containing a range of the spatially spaced frequency components. In a double-pass version, a retroreflector is disposed to effect a double pass of the light beam through the grating and the phase shifters. The arrangement is effecting in reducing chromatic dispersion of the optical signal.
    Type: Grant
    Filed: June 7, 2002
    Date of Patent: February 27, 2007
    Assignees: JDS Uniphase Inc., JDS Uniphase Corporation
    Inventors: Valentine N. Morozov, Sheldon McLaughlin, Thomas Ducellier
  • Patent number: 7184410
    Abstract: A method and system for using optical phase conjugation in an optical communications network including an add-drop multiplexer. The method includes determining a position for an optical phase conjugator such that channel quality for a channel in improved above a threshold. Transmission characteristics such as amplifier launch power or dispersion features may be adjusted to compliment the optical phase conjugation. An alternate method includes positioning the optical phase conjugator to improve a weighted average channel quality for the network.
    Type: Grant
    Filed: June 18, 2002
    Date of Patent: February 27, 2007
    Assignee: Ciena Corporation
    Inventors: Michael Y. Frankel, Harshad P. Sardesai
  • Patent number: 7184512
    Abstract: A clock generator is configured to generate, on the basis of an oscillation frequency clock of a voltage-controlled oscillator, a first signal having a phase the same as the oscillation frequency clock, a second signal having a phase delayed by a first phase amount to the first signal and a third signal having a phase delayed by a second phase amount to the first signal. A phase detection circuit is configured to provide a phase control on the basis of a phase difference between the third signal and an input signal. A frequency detection circuit is configured to sample the first and second signals synchronously with the input signal, thereby performing a frequency control for the voltage-controlled oscillator on the basis of the sampled signals.
    Type: Grant
    Filed: January 28, 2003
    Date of Patent: February 27, 2007
    Assignee: Sony Corporation
    Inventors: Toru Takeshita, Takashi Nishimura
  • Patent number: 7151898
    Abstract: A polarization mode dispersion (PMD) feedforward compensator compensates first and second order PMD. An optical signal is provided to a PMD detector that senses first and second order PMD in the optical signal and produces control signals for the PMD compensator. The PMD compensator comprises, in series, a first polarization controller, an adjustable delay, a second polarization controller, a first fixed delay, a third polarization controller and a second fixed delay.
    Type: Grant
    Filed: January 8, 2003
    Date of Patent: December 19, 2006
    Assignee: Massachusetts Institute of Technology
    Inventors: Poh-Boon Phua, Hermann A. Haud
  • Patent number: 6980744
    Abstract: Methods and systems for higher-order PMD compensation are implemented by developing an effective mathematical model and applying economical design techniques to the model. By assuming a constant precession rate for a narrow band of frequencies in an optical signal, a simplified model of a higher-order PMD compensator can be derived. The model can be used produce an economical compensator by making multiple uses of selected optical components.
    Type: Grant
    Filed: September 9, 2003
    Date of Patent: December 27, 2005
    Assignee: AT&T Corp.
    Inventors: Antonio Mecozzi, Jonathan A. Nagel, Mark Shtaif, Moshe Tur
  • Patent number: 6963675
    Abstract: The device according to the present invention relates to phase conjugate conversion and wavelength conversion. This device includes a polarization beam splitter and a polarization maintaining fiber (PMF). The polarization beam splitter has first, second, and third ports. The first port is supplied with signal light including first and second polarization components respectively having first and second polarization planes orthogonal to each other, and with pump light. The first and second ports are coupled by the first polarization plane, and the first and third ports are coupled by the second polarization plane. The PMF has first and second ends, and has a polarization mode to be maintained between the first and second ends. The first end is optically connected to the second port so that the first polarization plane is adapted to the polarization mode, and the second end is optically connected to the third port so that the second polarization plane is adapted to the polarization mode.
    Type: Grant
    Filed: August 21, 2003
    Date of Patent: November 8, 2005
    Assignee: Fujitsu Limited
    Inventor: Shigeki Watanabe
  • Patent number: 6915081
    Abstract: The invention provides a PLL circuit wherein, even if the duty ratio of an input signal varies, stabilized PLL operation is achieved. The PLL circuit includes a phase detection circuit and a frequency detection circuit. The frequency detection circuit includes a pair of D-type flip-flops for sampling first and second clock signals having different phases from each other in synchronism with an input signal at each rising or falling changing point of the input signal for each period, and a control logic circuit for logically operating the signals sampled by the D-type flip-flops and the signals sampled successively subsequently by the D-type flip-flops. The control logic circuit generates an UP pulse signal or a DOWN pulse signal based on a result of the arithmetic operation.
    Type: Grant
    Filed: October 17, 2001
    Date of Patent: July 5, 2005
    Assignee: Sony Corporation
    Inventors: Toru Takeshita, Takashi Nishimura
  • Publication number: 20040234274
    Abstract: The desirable effects of an optical phase conjugator are accompanied by a frequency shift with reversal of the frequency order of channels in a multichannel optical communication system. Such effects are rectifiable by employing a sequence involving demultiplexing the multichannel signal, operating on the individual, demultiplexed channel with a corresponding optical phase conjugator or frequency shifter followed by multiplexing the signal. This sequence is combined with a complementary operation—optical phase conjugator to complement a frequency shifting sequence or frequency shifting to complement an optical phase conjugating sequence.
    Type: Application
    Filed: May 20, 2003
    Publication date: November 25, 2004
    Inventors: Aref Chowdhury, Rene-Jean Essiambre
  • Publication number: 20040234275
    Abstract: The required penalty in the optical signal-to-noise ratio induced by nonlinear effects in an optical communication system is reduced by specific expedients. The communication system is operated and is adapted to be operated in a pseudo-linear regime. Further, an optical phase conjugator is employed with a suitable dispersion map. This combination yields a desirable improvement in the required penalty in the optical signal-to-noise ratio due to nonlinear effects.
    Type: Application
    Filed: May 20, 2003
    Publication date: November 25, 2004
    Inventors: Aref Chowdhury, Rene'-Jean Essiambre
  • Patent number: 6823138
    Abstract: An OPC generates a pump light having the wavelength &lgr;s with a power larger than a threshold for generating a nonlinear effect in an optical fiber for a main signal having the wavelengths &lgr;1 through &lgr;4 transmitted from an OS, and wavelength-multiplexes the generated light with the main signal. When the pump light induces a nonlinear effect, a signal light having the wavelengths &lgr;1′ through &lgr;4′ is generated symmetrically to a main signal having the wavelength &lgr;1 through &lgr;4 about the pump light on a wavelength axis. Thus, in a wavelength multiplexing system designed based on an eight-wave transmission, a signal light can function as a compensation light even when only four waves are used at the initialization of the system, thereby compensating for the characteristics of the system operations. Furthermore, the system is effective in cost because it simply requires an OPC for generating a pump light regardless of the number of compensation lights to be generated.
    Type: Grant
    Filed: October 8, 2002
    Date of Patent: November 23, 2004
    Assignee: Fujitsu Limited
    Inventor: Naohiro Shinoda
  • Patent number: 6823144
    Abstract: An optical transmission system is provided which uses optical single-sideband (SSB) modulation and incorporates at least one mid-span analog SSB regenerator arranged to produce a phase conjugation of the transmitted signal. The phase conjugation technique, referred to here as complementary sideband regeneration (CSR), is accomplished on the retransmitted optical signal in the electrical domain, and requires no nonlinear optical techniques.
    Type: Grant
    Filed: June 26, 2001
    Date of Patent: November 23, 2004
    Assignee: Lucent Technologies Inc.
    Inventor: Howard Roy Stuart
  • Patent number: 6792168
    Abstract: A device for compensating the polarization dispersion suffered by an optical signal when it is transmitted by an optical line includes a polarization controller. It generates a differential time delay between two orthogonal polarization modes and controls the polarization controller so that it converts the signal transmitted by the line into a compensated optical signal. If the quality of the compensated optical signal remains below a reference quality the device modifies the state of polarization of the optical signal. Applications include long distance optical transmission via standard fibers.
    Type: Grant
    Filed: July 30, 2002
    Date of Patent: September 14, 2004
    Assignee: Alcatel
    Inventors: Stéphanie Lanne, Jean-Pierre Hamaide, Denis Penninckx