Using Delay Patents (Class 398/161)
  • Patent number: 10447408
    Abstract: A communication system comprising n transmitters and a receiver, where n is an integer of at least 2, each of said n transmitters comprising a light source and an encoder such that each transmitter is adapted to output an encoded pulse of light, said receiver comprising a first element, the system further comprising a timing circuit, the timing circuit being configured to synchronize the encoded pulses output by the transmitters such that interference between a light pulse sent from the first transmitter and a light pulse from the second transmitter, interfere at the first element, each transmitter further comprising a suppressing element adapted to stop light exiting one of the transmitters such that the system is switchable between a first operation mode where two transmitters output encoded pulses and where both pulses interfere at the interference element and a second mode of operation where just one transmitter transmits light pulses to said receiver, the suppressing element being controlled to stop ligh
    Type: Grant
    Filed: January 18, 2017
    Date of Patent: October 15, 2019
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Marco Lucamarini, Bernd Matthias Frohlich, James Dynes, Zhiliang Yuan, Andrew James Shields
  • Patent number: 10234706
    Abstract: Photonic devices for generating linearly frequency modulated arbitrary microwave signals comprise a laser, and assembly for forming the emitted signal and a photoreceiver the passband of which is in the domain of the microwave frequencies. The forming assembly comprises: a first beam splitter; a first optical channel including a frequency-shifting loop comprising a beam splitter, a first optical amplifier, an optical isolator, a first spectral optical filter and an acousto-optical frequency shifter; a second optical channel including an electro-optical frequency shifter; a second beam splitter; a second optical amplifier; and a second optical filter; the acousto-optical frequency shift, the electro-optical frequency shift and the amplification gain of the first optical amplifier being adjustable.
    Type: Grant
    Filed: October 20, 2016
    Date of Patent: March 19, 2019
    Assignees: CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE, UNIVERSITE GRENOBLE ALPES, INSTITUT NATIONAL DE LA RECHERCHE SCIENTIFIQUE
    Inventors: Hugues Guillet De Chatellus, José Azana
  • Patent number: 10054806
    Abstract: Systems and methods therefor relating generally to electro-absorption modulation are disclosed. In a system thereof, a waveguide is for propagating an optical signal. A segmented electro-absorption modulator (“SEAM”) includes: a segmented anode having at least two anode segments spaced apart from one another alongside a first side of the waveguide; and a segmented cathode having at least two cathode segments spaced apart from one another alongside a second side of the waveguide corresponding to the at least two anode segments.
    Type: Grant
    Filed: November 8, 2016
    Date of Patent: August 21, 2018
    Assignee: XILINX, INC.
    Inventors: Sen Lin, Kun-Yung Chang, Austin H. Lesea
  • Patent number: 10050722
    Abstract: A signal generator includes an optical pulse source to provide a plurality of optical pulses; a photosensitive element configured to receive optical pulses and to produce an electrical signal from optical pulses 6, electrical signal 10 including a spectrum that includes a plurality of discrete frequencies that occur at a repetition rate corresponding to that of the optical pulses or a harmonic thereof; a frequency selector to receive the electrical signal from the photosensitive element, to select dynamically the harmonic from the electrical signal and to communicate the dynamically selected harmonic; a direct digital synthesizer (DDS) to receive the harmonic of the electrical signal from the frequency selector and to produce a first output; and a frequency converter to receive the harmonic from the frequency selector and the first output from the DDS, wherein the frequency converter shifts a frequency of the harmonic by an amount substantially equal to a frequency of the first output from the DDS to produce
    Type: Grant
    Filed: September 30, 2015
    Date of Patent: August 14, 2018
    Assignee: The United States of America, as Represented by the Secretary of Commerce
    Inventors: Franklyn J. Quinlan, Scott Diddams, Tara Fortier, Antoine Rolland
  • Patent number: 9983069
    Abstract: A measuring apparatus includes a light source unit configured to generate probe light, a bifurcating unit configured to cause Brillouin backscattered light occurring from the probe light to bifurcate into first light, which propagates through a first optical path, and second light, which propagates through a second optical path, a delay unit configured to delay one of the first light and the second light, an optical multiplexer configured to multiplex the first light and the second light to generate multiplexed light, and a coherent detector configured to perform homodyne detection of the multiplexed light and to output a difference frequency obtained as a result of the detection as a phase-difference signal.
    Type: Grant
    Filed: January 14, 2016
    Date of Patent: May 29, 2018
    Assignee: Oki Electric Industry Co., Ltd.
    Inventor: Kengo Koizumi
  • Patent number: 9225424
    Abstract: In a PON system in which plural kinds of modulation schemes coexist, when uplink burst signals from respective ONUs are received, the receiving efficiency degrades as the number of the times of switching of the modulation scheme increases. In an optical access (PON) system supporting plural kinds of modulation schemes, an OLT allocates bandwidths for uplink signals, i.e., transmission timings each including a transmission start time and a transmission duration, to ONUs, respectively, such that the bandwidths allocated to plural ONUs for the same modulation scheme are as successive as possible. Based on the transmission timings allocated to the respective ONUs, the OLT switches the modulation scheme of a modulation-scheme variable burst-mode optical transmitter/receiver by control of a modulation scheme controller.
    Type: Grant
    Filed: October 29, 2013
    Date of Patent: December 29, 2015
    Assignee: Hitachi, Ltd.
    Inventors: Toshiyuki Odaka, Jun Sugawa, Hidehiro Toyoda
  • Patent number: 9225418
    Abstract: The invention relates to a device for measuring the profile of a single pulse or a pulse with a very low repetition rate, comprising replication means (100,105,120,125,130) for generating a series of replica pulses of an initial optical pulse (I), with a recurrence period (?); means (100b,150) for extracting said replica pulses; optical sampling means (160,161) for sampling the extracted replica pulses (Ri) to output optical samples (Ei) from the extracted replica pulses (Ri) with a sampling period (Te), the deviation between the sampling period and the recurrence period being chosen to be not equal to zero and very much less than the recurrence period; detection means (180) for obtaining an electrical signal from optical samples (Ei) output by said optical sampling means (160,161); said replication means comprising parametric amplification means (120,140,141,142) for amplifying said replica pulses.
    Type: Grant
    Filed: November 14, 2006
    Date of Patent: December 29, 2015
    Assignee: COMMISSARIAT A L'ENERGIE ATOMIQUE
    Inventors: Alain Jolly, Arnaud Mussot
  • Patent number: 9031421
    Abstract: Provided is a method of measuring signal transmission time difference of a measuring device. The measuring device according to embodiments, by measuring a skew on two optical paths through signal delays of sufficient sizes for skew measurement on the optical paths, even a skew having a minute size can be measured within a measurable range.
    Type: Grant
    Filed: July 3, 2013
    Date of Patent: May 12, 2015
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Joong-Seon Choe, Chun Ju Youn, Jong-Hoi Kim, Duk Jun Kim, Yong-Hwan Kwon, Kwang-Seong Choi, Eun Soo Nam
  • Patent number: 9020341
    Abstract: An optical transmission system includes at least a first optical link to transmit a first data signal as a part of a multi-lane signal and a second optical link to transmit a second data signal as another part of the multi-lane signal; on the transmission side, a reference clock is constantly applied to the first data signal of the first optical link, and a delay clock is applied to the second data signal responsive to a control signal on the second optical link; on the receiving side, the phase of a first clock signal detected from the first data signal received on the first optical link and the phase of a second clock signal detected from the second data signal received on the second optical link are compared, and the control signal is detected from the comparison result.
    Type: Grant
    Filed: January 4, 2013
    Date of Patent: April 28, 2015
    Assignee: Fujitsu Limited
    Inventor: Tsuyoshi Yamamoto
  • Patent number: 9002209
    Abstract: Disclosed are a forward discrete/inverse-discrete Fourier transform device and method for optical orthogonal frequency division multiplexing (OFDM) communication and a transmitting and receiving apparatus. The forward inverse-discrete Fourier transform device includes N 1:N splitters for splitting subcarrier signals received from N inputs corresponding to the number of optical frequencies of subcarriers, a phase shift delay array module for shifting phases of the split signals from the 1:N splitters, N N:1 power couplers for coupling signals output from the phase shift delay array module, a time delay array module for performing time delay on optical OFDM symbols from the N:1 power couplers, and an N:1 power coupler for coupling signals output from the time delay array module.
    Type: Grant
    Filed: March 6, 2012
    Date of Patent: April 7, 2015
    Assignee: ICU Research and Industrial Cooperation Group
    Inventors: June Koo Rhee, Kyu Sang Lee, Chan T. D. Thai
  • Publication number: 20150071653
    Abstract: An optical communication system, a transmitter, a receiver, and methods of operating the same are provided. In particular, a transmitter is disclosed as being configured to encode optical signals in accordance with a multi-level coding scheme. The receiver is configured to provide skew correction to the optical signals received from the transmitter by dividing a received signal into separate level-specific components and sampling each of the components with distinct sampling blocks.
    Type: Application
    Filed: September 6, 2013
    Publication date: March 12, 2015
    Applicant: Avago Technologies General IP (Singapore) Pte.Ltd.
    Inventors: Mike Allen Robinson, David W. Dolfi
  • Patent number: 8976445
    Abstract: Methods, systems and devices implement optical tapped delay lines. In one aspect, a device includes an optical tapped delay (TDL) including a wavelength conversion element, and a dispersive element, coupled with the wavelength conversion element, to impose a relative delay to an optical signal. The optical TDL can include a nonlinear element to combine signals in a phase coherent manner. The wavelength conversion element can include an optical nonlinear device such as a periodically poled lithium niobate (PPLN) or a highly nonlinear fiber (HNLF) with a high nonlinear coefficient and a low dispersion slope to effect four-wave mixing (FWM). The dispersive element can have a low dispersion slope, and the delays effected by the optical TDL can be tunable.
    Type: Grant
    Filed: March 4, 2013
    Date of Patent: March 10, 2015
    Assignee: University of Southern California
    Inventors: Alan E. Willner, Mohammad R. Chitgarha, Salman Khaleghi, Omer F. Yilmaz
  • Patent number: 8958704
    Abstract: The invention relates to a method of generating a feedback signal for adjusting a polarization mode dispersion compensator (PMDC, 21) in a transmission system with alternate-polarization. A first signal (37) is determined by measuring a spectral component of the radio frequency modulation of an optical signal (33) at a particular radio frequency. Preferably, the radio frequency essentially corresponds to half the symbol rate of the optical signal (33). Also a second signal (35) is determined by coupling the optical signal (33) into a delay line interferometer (DLI, 50) having a delay essentially corresponding to the symbol period or an odd multiple of the symbol period between its arms (51, 54). Downstream of the DLI (50), the signal is optical-to-electrically converted. Downstream of the optical-to-electrical conversion, an intensity measurement is performed. The first (37) and second (35) signals are then combined to generate the feedback signal (28).
    Type: Grant
    Filed: November 7, 2008
    Date of Patent: February 17, 2015
    Assignee: Alcatel Lucent
    Inventors: Axel Klekamp, Henning Bülow
  • Patent number: 8891979
    Abstract: A photon detection system including a photon detector configured to detect single photons, a signal divider to divide the output signal of the photon detector into a first part and a second part, wherein the first part is substantially identical to the second part, a delay mechanism to delay the second part with respect to the first part, and a combiner to combine the first and delayed second parts of the signal such that the delayed second part is used to cancel periodic variations in the first part of the output signal.
    Type: Grant
    Filed: February 29, 2008
    Date of Patent: November 18, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Zhiliang Yuan, Andrew James Shields
  • 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: 8837956
    Abstract: A receiver or spectrum determiner includes stages, Fourier transforms, phase delays and a summer. The stages are coupled are in pipelined fashion along a signal path. Each of the stages has a respective output for providing at least one respective demodulated signal for the stage. The Fourier transforms are for receiving the respective demodulated signal and providing a respective Fourier transform. The phase delays each have a delay associated with the respective stage. Each phase delay is for receiving the respective Fourier transform and providing a respective phase delayed transform in accordance with the respective stage. The summer is for summing the respective phase delayed Fourier transform from each phase delay. The receiver can be an electronic intelligence (ELINT) receiver.
    Type: Grant
    Filed: June 28, 2012
    Date of Patent: September 16, 2014
    Assignee: Rockwell Collins, Inc.
    Inventors: Raymond Zanoni, Mark A. Willi, Roger A. Dana
  • Patent number: 8818201
    Abstract: This concerns a protected long-reach PON having a plurality of terminals connected to a distribution network that is fed by both a main and back up feed, each feed including a head end and a repeater. The back up head end had access to a ranging table with data previously obtained by the main head end, thereby speeding up the switch over in the event of a fault with the main feed. In one embodiment, the repeater has a virtual ONU therein, allowing the back up repeater to be ranged by the back up head end, thereby yet further speeding up the ranging procedure. The main and back up repeaters are sufficiently equidistant from the distribution network to allow the back up head to perform normal scheduling without performing a ranging operation on each of the terminals, even if the different terminals transmit at slightly different wavelengths. This is achieved using the ranging information obtained with regard to the back up repeater.
    Type: Grant
    Filed: October 23, 2008
    Date of Patent: August 26, 2014
    Assignee: British Telecommunications plc
    Inventor: Peter Healey
  • Patent number: 8805200
    Abstract: An optical transmission system includes a polarization multiplexing optical transmitter for transmitting an optical signal, where an X-polarized signal and a Y-polarized signal each having a having predetermined frame structure are polarization-multiplexed, to an optical fiber transmission path, and a polarization multiplexing receiver for receiving the optical signal that has propagated through the optical transmission path. The polarization multiplexing optical transmitter delays a frame assignment signal (FAS) in the Y-polarized signal, by a predetermined delay time ?, relative to FAS in the X-polarized signal.
    Type: Grant
    Filed: March 2, 2011
    Date of Patent: August 12, 2014
    Assignee: Fujitsu Telecom Networks Limited
    Inventor: Shota Mori
  • 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: 8786821
    Abstract: A polarization controller includes a first polarization controller, a demultiplexer, a second polarization controller, and a multiplexer. The first polarization controller controls the state of polarization of input light such that a part of the wavelength components of the input light is in a first state of polarization. The demultiplexer demultiplexes the light output from the first polarization controller into a plurality of wavelength components. The second polarization controller controls the plurality of wavelength components in a second state of polarization by using liquid crystal modulation devices. The multiplexer multiplexes the plurality of wavelength components output from the second polarization controller.
    Type: Grant
    Filed: May 14, 2010
    Date of Patent: July 22, 2014
    Assignee: Fujitsu Limited
    Inventor: Takashi Shiraishi
  • Patent number: 8774262
    Abstract: Methods, apparatuses, and systems are presented for performing adaptive equalization involving receiving a signal originating from a channel associated with inter-symbol interference, filtering the signal using a filter having a plurality of adjustable tap weights to produce a filtered signal, and adaptively updating each of the plurality of adjustable tap weights to a new value to reduce effects of inter-symbol interference, wherein each of the plurality of adjustable tap weights is adaptively updated to take into account a constraint relating to a measure of error in the filtered signal and a constraint relating to group delay associated with the filter. Each of the plurality of adjustable tap weights may be adaptively updated to drive group delay associated with the filter toward a target group delay.
    Type: Grant
    Filed: March 25, 2011
    Date of Patent: July 8, 2014
    Assignee: Vitesse Semiconductor Corporation
    Inventors: Sudeep Bhoja, John S. Wang, Hai Tao
  • Patent number: 8718482
    Abstract: One or more devices of a network having asymmetric delay are configured to participate in time synchronization protocol sessions in which a client device synchronizes its local clock to a master device. In one example, a system includes an optical line terminal configured to receive a time synchronization protocol packet from a grandmaster clock and an optical network unit (ONU) configured to calculate a residence time of the time synchronization protocol packet, encode the residence time into the packet, and to forward the packet to a client device. Moreover, the system may participate in a plurality of time synchronization protocol sessions with a plurality of client devices, such that the client devices become synchronized in frequency and phase.
    Type: Grant
    Filed: November 9, 2010
    Date of Patent: May 6, 2014
    Assignee: Calix, Inc.
    Inventors: Harold A. Roberts, Christopher T. Bernard, Jason W. Dove, Berkay Baykal
  • Patent number: 8718474
    Abstract: Methods and devices for compensating for chromatic dispersion are shown that include receiving an input data signal, applying a filter to the data signal, and outputting a CD compensated signal. Applying the filter includes convolving known filter coefficients with a plurality of delayed versions of the data signal using addition and at least one inverse sign operation or using lookup tables and combining outputs to produce a CD compensated signal.
    Type: Grant
    Filed: October 6, 2011
    Date of Patent: May 6, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Dayou Qian, Junqiang Hu, Ting Wang, Yoshiaki Aono, Tsutomu Tajima
  • Patent number: 8712252
    Abstract: To efficiently apply jitter to an optical signal using a simple configuration, provided is an optical signal output apparatus that outputs an optical pulse pattern signal including jitter, the optical signal generating apparatus comprising a light source section that outputs an optical signal having an optical frequency corresponding to a frequency control signal; an optical modulation section that modulates the optical signal output by the light source section, according to a designated pulse pattern; and an optical jitter generating section that delays an optical signal passed by the optical modulation section according to the optical frequency, to apply jitter to the optical signal.
    Type: Grant
    Filed: October 18, 2011
    Date of Patent: April 29, 2014
    Assignee: Advantest Corporation
    Inventors: Shin Masuda, Kazunori Shiota
  • Patent number: 8712248
    Abstract: An apparatus for simulating radio frequency (RF) signal propagation characteristics in a wireless communication network is disclosed. The apparatus includes a first RF terminal and a second RF terminal. A first optical modulator is in electrical communication with the first RF terminal. An optical delay line is in optical communication with the first optical modulator. A first optical demodulator is in optical communication with the optical delay line and in electrical communication with the first RF terminal. A second optical demodulator is in optical communication with the optical delay line and in electrical communication with the second RF terminal. A second optical modulator is in electrical communication with the second RF terminal and in optical communication with the optical delay line.
    Type: Grant
    Filed: March 12, 2013
    Date of Patent: April 29, 2014
    Assignee: Eastern Optx, Inc.
    Inventors: Joseph Mazzochette, Edward J. MacMullen, Jerome Lomurno
  • Patent number: 8670675
    Abstract: A distortion compensation circuit including a configurable delay may be used with one or more non-linear elements, such as a laser, to compensate for distortion generated by the non-linear element(s), for example, in broadband RF applications. Embodiments of the distortion compensation circuit may include a primary signal path with a configurable delay segment and a secondary signal path including at least one distortion generator. The configurable delay segment may be selectively configured to provide different delay settings to accommodate different RF loading conditions such that the delayed RF signal on the primary signal path is aligned with the distortion products generated on the secondary signal path when combined to form an RF signal with distortion compensation.
    Type: Grant
    Filed: December 22, 2010
    Date of Patent: March 11, 2014
    Assignee: Applied Optoelectronics, Inc.
    Inventors: Jun Zheng, Yi Wang
  • Patent number: 8655184
    Abstract: The present invention relates to a higher-order dispersion compensation device (210), the device being adapted to cooperate with a pair of optical components (P1, P2), e.g. a pair of prisms, being arranged to compensate first-order dispersion by separating different wavelengths spatially. The compensation device (210) has the form of a phase plate, wherein the phase change for each wavelength is adjusted by designing the height (h) at the corresponding position (x) of the plate so as to substantially compensate for higher-order dispersion. The invention is advantageous for obtaining a higher-order dispersion compensation device which is relatively simple to construct and use making it a quite cost-effective device. The invention also relates to a corresponding optical system and method for compensating dispersion where this is important, e.g. in a multiple-photon imaging system.
    Type: Grant
    Filed: May 20, 2009
    Date of Patent: February 18, 2014
    Assignee: Koninklijke Philips N.V.
    Inventors: Gert Het Hooft, Bernardus Hendrikus Wilhelmus Hendriks, Mischa Megens
  • Patent number: 8625996
    Abstract: An optical transmitter is provided for transmitting a wavelength multiplexed signal comprising an intensity modulation optical signal and a phase modulation optical signal through a transmission line. The optical transmitter includes a bit time difference given signal generator for generating at least two optical signals having a bit time difference therebetween, from the wavelength multiplexed signal. The optical transmitter further includes a wavelength multiplexed signal output unit to which at least two optical signals are input from the bit time difference given signal generator, and which generates and outputs a wavelength multiplexed signal in which the bit time difference was given between the phase modulation optical signal and the phase modulation optical signal.
    Type: Grant
    Filed: November 14, 2007
    Date of Patent: January 7, 2014
    Assignee: Fujitsu Limited
    Inventors: Toshiki Tanaka, Hisao Nakashima, Takeshi Hoshida, Toru Katagiri, Hiroki Ooi, Akira Miura
  • Patent number: 8588257
    Abstract: One embodiment of the present invention provides a system that accommodates different clock frequencies in an Ethernet passive optical network (EPON). The system receives a signal from an optical line terminal (OLT) at an optical network unit (ONU) and derives an OLT clock. The system also maintains a local clock. The system further receives from the OLT an assignment for an upstream transmission window, during which the ONU can transmit an upstream data burst to the OLT based on the local clock. The system adjusts the number of bits of the data burst without affecting the payload data carried in the data burst, thereby allowing the data burst to fit properly within the upstream transmission window and compensating for frequency differences between the local clock and the OLT clock. The system transmits the data burst based on the local clock in the upstream transmission window.
    Type: Grant
    Filed: March 28, 2011
    Date of Patent: November 19, 2013
    Assignee: Broadcom Corporation
    Inventors: Edward W. Boyd, Ryan E. Hirth, Hung Nguyen
  • Patent number: 8582983
    Abstract: A method and system for generating multi-subcarriers is disclosed. Re-circulating frequency shifters—based on the frequency shifting in two cascading phase modulators—are used to generate 112 subcarriers with stable architecture since there is no direct current bias in phase modulators.
    Type: Grant
    Filed: March 2, 2012
    Date of Patent: November 12, 2013
    Assignees: ZTE Corporation, ZTE (USA) Inc.
    Inventor: Jianjun Yu
  • Patent number: 8571412
    Abstract: An apparatus for simulating radio frequency (RF) signal propagation characteristics in a wireless communication network is disclosed. The apparatus includes a first RF terminal and a second RF terminal. A first optical modulator is in electrical communication with the first RF terminal. An optical delay line is in optical communication with the first optical modulator. A first optical demodulator is in optical communication with the optical delay line and in electrical communication with the first RF terminal. A second optical demodulator is in optical communication with the optical delay line and in electrical communication with the second RF terminal. A second optical modulator is in electrical communication with the second RF terminal and in optical communication with the optical delay line.
    Type: Grant
    Filed: November 6, 2012
    Date of Patent: October 29, 2013
    Assignee: Eastern Optx, Inc.
    Inventors: Joseph Mazzochette, Edward J. MacMullen, Jerome Lomurno
  • Patent number: 8548338
    Abstract: The present application describes methods and systems for use in a communications network. More specifically, a method of deploying an optical demodulator arrangement having at least one interferometer in a network that transmits an optical signal is provided. The optical signal may include one or more on-off-keyed signals and one or more DMPSK signals. In some embodiments, the DMPSK signal is a DQPSK signal. The network may include one or more of fiber spans carrying the signals. The interferometer may have a first optical path and a second optical path and a time delay is formed between the first and second optical paths. The method may involve determining a cross-talk penalty that results from cross-phase modulation between the channels, and determining a time delay value for the interferometer. The time delay value may be determined based at least in part on determined the cross-talk penalty.
    Type: Grant
    Filed: October 18, 2010
    Date of Patent: October 1, 2013
    Assignee: Oclaro Technology Limited
    Inventors: Nicholas John Doran, Donald Scott Govan, Brian Garrett
  • Patent number: 8526829
    Abstract: A PPM transmitter includes an optical clock generator for generating equally-spaced optical pulses with a sampling period T; an encoder for transforming an incoming waveform U(t) into a linear combination V(t) of U(t) and a delayed output V(t?kT) according to a rule V(t)=U(t)+aV(t?kT), where k is a positive integer, V(t) is voltage generated by the encoder and a is a coefficient; and an optical delay generator for delaying optical pulses generated by the optical clock generator in proportion to the voltage V(t), such that ?tn=bV(t), where b is another coefficient and where ?tn is the amount of delay imposed by the optical delay generator. The PPM transmitter functions with a PPM receiver for communicating data without the need to transmit or otherwise provide a clock signal. The PPM receiver decodes an original series of the delayed optical pulses Q(t) and a second series Q(t?ckT) delayed by ckT where c is a coefficient.
    Type: Grant
    Filed: August 25, 2010
    Date of Patent: September 3, 2013
    Assignee: HRL Laboratories, LLC
    Inventors: Daniel Yap, Irina Ionova
  • Patent number: 8521038
    Abstract: A robustly stabilized communication laser can output a multimode optical signal remaining aligned to a coordinate of a dense wavelength division multiplexing (“DWDM”) grid while responding to a fluctuating condition or random event, such as, without limitation, exposure to a temperature fluctuation, stray light, or contamination. Responsive to the fluctuating condition, energy can transfer among individual modes in a plurality of aligned longitudinal modes. Modes shifting towards a state of misalignment with the DWDM coordinate can attenuate, while modes shifting towards a state of alignment can gain energy. Fabrication processes and systems and light management, such as beam steering, epoxy scaffolds, spectral adjustments, mode matching, thermal expansion control, alignment technology, etc. can facilitate nano-scale control of device parameters and can support low-cost fabrication.
    Type: Grant
    Filed: May 6, 2011
    Date of Patent: August 27, 2013
    Assignee: Cirrex Systems, LLC
    Inventor: Michael L. Wach
  • Patent number: 8515288
    Abstract: An optical signal transmission control apparatus that controls transmission of optical signals transmitted via a plurality of redundant routes. The optical signal transmission control apparatus includes a delay difference adjusting unit that adjusts a transmission delay difference between the optical signals of each route by converting a wavelength of the optical signal and making the optical signal with a converted wavelength pass through a waveguide in which a transmission delay of the optical signal changes continuously depending on the wavelength, and a waveform degradation compensating unit that compensates degradation of a waveform of the optical signal, while maintaining the transmission delay difference adjusted by the delay difference adjusting unit.
    Type: Grant
    Filed: June 19, 2009
    Date of Patent: August 20, 2013
    Assignee: Fujitsu Limited
    Inventor: Futoshi Izumi
  • Patent number: 8515287
    Abstract: The optical transmission equipment includes: a demultiplexer for demultiplexing a transmitted wavelength-multiplexed optical signal to first and second optical signals; a first variable dispersion compensation unit; a second variable dispersion compensation unit; a first error detector; a second error detector; and a dispersion compensation control unit for controlling dispersion compensation amounts of the first and second variable dispersion compensation units based on the detection result of the first or second error detector. Upon detection of a signal error in the first optical signal, the first variable dispersion compensation unit is controlled to change from a first compensation amount to a third compensation amount, and the second variable dispersion compensation unit is controlled to change from a second compensation amount to a fourth compensation amount.
    Type: Grant
    Filed: June 10, 2008
    Date of Patent: August 20, 2013
    Assignee: Hitachi, Ltd.
    Inventors: Kenichi Ogawa, Kazuhiro Watanabe, Hiroyuki Nakano
  • Patent number: 8478135
    Abstract: An optical receiver includes a two-stage constant modulus algorithm (CMA) equalizer. The first stage is a modified version of a CMA equalizer and the second stage is a conventional CMA equalizer. The first stage may be made up of four sub-equalizers, of which only two of the sub-equalizers are independent, i.e., uncorrelated to each other. This first stage equalizer compensates for polarization-mode dispersion (PMD). The second stage equalizer is a conventional CMA equalizer made up of four sub-equalizers that are adjusted independently. This second stage equalizer may compensate for polarization-dependent loss (PDL). The receiver includes a first processor that determines PMD information based on a plurality of transfer function parameters of the modified CMA equalization of the first stage equalizer and the modified-equalized output and a second processor that determines PDL based on a plurality of transfer function parameters of the CMA equalization of the second stage equalizer.
    Type: Grant
    Filed: June 30, 2010
    Date of Patent: July 2, 2013
    Assignee: Alcatel Lucent
    Inventor: Chongjin Xie
  • Patent number: 8467677
    Abstract: A method for monitoring a passive optical network (1), PON, having a tree-like structure with a main line (3) and at least two branches (6.1 to 6.3), comprising: transmitting a wake-up signal (10) from the main line (3) to at least two monitoring units (DPM1 to DPM3) arranged in the at least two branches (6.1 to 6.3), in each of the monitoring units (DPM1 to DPM3), detecting the wake-up signal (10) and transmitting a response signal (A, B, C) back to the main line (3), each of the monitoring units (DPM1 to DPM3) generating a pre-defined time delay (?tA to ?tC) between the detection of the wake-up signal (10) and the start of the transmission of the response signal (A, B, C), and receiving the response signals (A, B, C) at the main line (3), the receiving times (R1 to R3) of the response signals (A, B, C) being different from each other, the difference between the receiving times (R1 to R3) being adjusted by the pre-defined time delays (?tA to ?tC) of the monitoring units (DPM1 to DPM3).
    Type: Grant
    Filed: January 27, 2009
    Date of Patent: June 18, 2013
    Assignee: Alcaltel Lucent
    Inventors: Michael Straub, Harald Schmuck, Lothar Jentsch, Jörg Hehmann
  • Patent number: 8452187
    Abstract: An apparatus for simulating radio frequency (RF) signal propagation characteristics in a wireless communication network is disclosed. The apparatus includes a first RF terminal and a second RF terminal. A first optical modulator is in electrical communication with the first RF terminal. An optical delay line is in optical communication with the first optical modulator. A first optical demodulator is in optical communication with the optical delay line and in electrical communication with the first RF terminal. A second optical demodulator is in optical communication with the optical delay line and in electrical communication with the second RF terminal. A second optical modulator is in electrical communication with the second RF terminal and in optical communication with the optical delay line.
    Type: Grant
    Filed: December 2, 2010
    Date of Patent: May 28, 2013
    Assignee: Eastern Optx Inc.
    Inventors: Joseph Mazzochette, Edward J. MacMullen, Jerome Lomurno
  • Patent number: 8433204
    Abstract: A phase shift keyed demodulator includes first and second beam splitters, a first optical path, a second optical path, and a wavelength tuner. The first beam splitter splits an input signal into first and second output signals. The second beam splitter splits each first and second output signal into a transmitted signal and a reflected signal. The first optical path includes an optical path of each transmitted signal from a beam splitting surface to a reflector and back to the beam splitting surface. The second optical path includes an optical path of each reflected signal from the beam splitting surface to a mirror surface and back to the beam splitting surface. A path difference introduces a delay between the transmitted signal and the reflected signal. The wavelength tuner tunes the demodulator to a predetermined central wavelength and introduces a phase shift between first and second transmitted signals.
    Type: Grant
    Filed: December 23, 2010
    Date of Patent: April 30, 2013
    Assignee: Finisar Corporation
    Inventors: Huiping Li, Xiaolin Chen, Fan Chen, Fahua Lan, Dapeng Kevin Zhang
  • Patent number: 8358931
    Abstract: An optoelectronic timing system includes an optical timing compensation system in which optical pulses developed by a semiconductor laser are advanced or retarded based upon an expected arrival time. The pulses are directed into a number of time-quantifiable optical paths. Time quantification for a pulse is based upon the time required for a pulse to travel a particular length at the speed of light. Pulses are directed into an advancing path or a retarding path by optical switches which compare an expected arrival time of a new pulse to an expected arrival time based on a previous pulse. The optical compensation system is incorporated into a precision timing device in which multiple optical paths, having decreasing lengths in a defined pattern, are arranged in serial fashion so as to have each subsequent path of the series represent a travel time one order of magnitude different than a travel time of an adjacent path.
    Type: Grant
    Filed: October 22, 2003
    Date of Patent: January 22, 2013
    Inventor: James P. Siepmann
  • Publication number: 20130016982
    Abstract: An adjustable delayer for adjustably delaying an input signal based on a delay adjustment input information describing a desired delay includes a plurality of series-connected tunable delay circuits, wherein a first of the tunable delay circuits is configured to receive the input signal. The adjustable delayer also includes a closed-loop control circuit configured to provide a first delay tuning information to tune a combined delay of the plurality of tunable delay circuits to fulfill a predetermined condition. The adjustable delayer also includes a combiner to combine the first delay tuning information with a second delay tuning information, that is based on the delay adjustment input information, to obtain a combined delay tuning information. The adjustable delayer is configured to tune a delay of one or more of the tunable delay circuits based on the combined delay tuning information.
    Type: Application
    Filed: July 15, 2011
    Publication date: January 17, 2013
    Applicant: Intel Mobile Communications GmbH
    Inventor: Stephan Henzler
  • Patent number: 8346094
    Abstract: A light transmission system has a light transmission module having a light transmission path that transmits a data signal as an optical signal, wherein the light transmission module converts the optical signal transmitted through the light transmission path to an electrical signal and outputs the converted optical signal as a binarization signal, an electrical transmission path that outputs a clock signal as a binarization signal, a reception processing unit that performs a reception process on each of the data signal and the clock signal, and a first delay unit that delays a rise start time of the clock signal with respect to a rise start time of the data signal for the binarization signal. A delay amount of the clock signal by the first delay unit is a time less than or equal to a maximum value of a data dependency jitter (DDJ).
    Type: Grant
    Filed: November 18, 2009
    Date of Patent: January 1, 2013
    Assignee: OMRON Corporation
    Inventors: Kentaro Hamana, Naru Yasuda, Hayami Hosokawa
  • Patent number: 8346099
    Abstract: The present invention converts each of the optical differential signals from DPSK demodulator from an optical signal into an electrical signal by using optical-electrical signal converters. Thereafter, each electrical signal is subjected to amplification adjustment at an appropriate amplification factor by variable amplifier, and an appropriate delay amount is added to each electrical signal by variable delay line, and thereafter data discrimination is performed by discriminator. Since two differential signals after DPSK demodulation are subjected to amplitude and delay adjustments, the need for optical parts is obviated enabling the use of electric circuits which can be integrated. Thus, the cost of the optical reception device will be reduced. Moreover, the since electric signals whose phases and amplitudes are equalized are inputted to discriminator, erroneous determination of data at discriminator will be reduced.
    Type: Grant
    Filed: November 29, 2007
    Date of Patent: January 1, 2013
    Assignee: NEC Corporation
    Inventors: Satomi Shioiri, Kiyoshi Fukuchi
  • Patent number: 8331779
    Abstract: An OADM in a wavelength division multiplexing transmission system includes a wavelength selection switch that selects a predetermined wavelength from a multiple optical signal obtained by multiplexing a phase modulated signal and an intensity modulated signal and outputs the selected wavelength signal to a predetermined output port. The wavelength selection switch has a different delay for each wavelength of the multiple optical signal. For example, the wavelength selection switch includes a mirror array. Optical paths from the surfaces of mirrors arranged on the mirror array to the diffraction grating are different in the case of adjacent mirrors.
    Type: Grant
    Filed: March 2, 2010
    Date of Patent: December 11, 2012
    Assignee: Fujitsu Limited
    Inventors: Hiroki Ooi, Akira Miura, Tsuyoshi Yamamoto, Naoki Hashimoto
  • Patent number: 8326146
    Abstract: The invention relates to a communications node (10) for routing an optical signal 5 comprising at least one data packet, the node (10) having an input optic fiber (12) and an output optic fiber (14) in communication with each other, the input optic fiber (12) in communication with an optical splitter (20) which is arranged to split an incoming optical signal into at least two substantially identical optical signals, the optical splitter (20) further arranged to pass one of the optical signals to an optical correlator (22) and the other of the optical signals to an input optical switch (24), the optical correlator (22) being arranged to compare an address of the packet with a reference address (40) and to generate a trigger if the reference address (40) matches the address of the packet, the input optical switch (24) being arranged to route the data packet to an optical to electrical converter (28) in response to the trigger.
    Type: Grant
    Filed: March 15, 2007
    Date of Patent: December 4, 2012
    Assignee: Telefonaktiebolaget L M Ericsson (publ)
    Inventor: Atilla Bader
  • Patent number: 8326153
    Abstract: A tunable dispersion compensator (TDC) is tuned from a first dispersion setpoint to a second dispersion setpoint while maintaining continuity of the dispersion. The dispersion tuning follows a pre-determined trajectory in the time domain, so that continuity of the optical dispersion across the channel optical bandwidth is maintained while minimizing all other TDC-induced optical impairments during a tuning period.
    Type: Grant
    Filed: April 9, 2010
    Date of Patent: December 4, 2012
    Assignee: Oclaro (North America), Inc.
    Inventors: Lan Sheng, Aaron Zilkie, Mark Summa, Timothy Kent Zahnley, Peter G. Wigley
  • 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: 8311415
    Abstract: A frequency up-conversion system includes an optical splitter, an optical modulator, an optical phase-shifter, and an optical coupler. In one embodiment of the present disclosure, the optical splitter is configured to split an optical wave into a first optical wave and a second optical wave, the optical modulator is configured to modulate the first optical wave to form a modulation wave, the optical phase-shifter is configured to shift the phase of the second optical wave by a predetermined phase to form a shifting wave, and the optical coupler is configured to couple the modulation wave and the shifting wave. In one embodiment of the present disclosure, the optical modulator and the optical phase-shifter are connected in a parallel manner.
    Type: Grant
    Filed: April 15, 2010
    Date of Patent: November 13, 2012
    Assignee: Industrial Technology Research Institute
    Inventors: Chun Ting Lin, Wen Jr Jiang, Jyehong Chen, Sien Chi, Dar Zu Hsu
  • Patent number: 8306434
    Abstract: A signal-transmitting system includes a digital-to-analog converter, an optical modulator, first and second electrodes, an optical phase shifter, and an optical coupler. The digital-to-analog converter converts digital data into an electrical analog signal. The optical modulator includes a first optical waveguide configured to transmit a first optical carrier, a second optical waveguide configured to transmit a second optical carrier, a first electrode positioned on the first optical waveguide, and a second electrode positioned on the second optical waveguide. The first and second electrical couplers are configured to couple respective electrical analog signals and electrical carriers to electrodes to generate modulation waves. The modulation waves are different in phase. The optical phase shifter is configured to shift the second modulation wave by a predetermined phase, and the optical coupler is configured to couple the first and second modulation waves to generate an optical output signal.
    Type: Grant
    Filed: April 15, 2010
    Date of Patent: November 6, 2012
    Assignee: Industrial Technology Research Institute
    Inventors: Chun Ting Lin, Wen Jr Jiang, Jyehong Chen, Sien Chi, Dar Zu Hsu