Reducing Distortion Or Dispersion Patents (Class 398/159)
  • Patent number: 10225043
    Abstract: [Object] To provide a new and improved information processing apparatus, information processing method, and program, capable of improving technology related to FEC for achieving a low delay transfer. [Solution] Provided is an information processing apparatus including: an acquisition unit which acquires a transfer bit rate; and a selection unit which selects an encoding system of forward error correction based on a comparison result between the transfer bit rate acquired by the acquisition unit and a threshold.
    Type: Grant
    Filed: May 23, 2014
    Date of Patent: March 5, 2019
    Assignee: SONY CORPORATION
    Inventor: Vijitha Ranatunga
  • Patent number: 10116390
    Abstract: Aspects of a method and system for feedback during optical communications are provided. In one embodiment, a system for optical communications comprises a predistortion module, a feedback subsystem, a transmit optical subsystem, and an external modulator. The predistortion module is operable to receive an input digital signal and modify the input digital signal to produce a digital predistorted signal. The transmit optical subsystem is operable to generate an optical signal from the digital predistorted signal. The modification of the input digital signal is dynamically controlled by the feedback subsystem according to one or more characteristics of the optical signal as determined by the feedback subsystem. The amplitude of the external modulator output is also dynamically controlled by the feedback subsystem.
    Type: Grant
    Filed: June 17, 2016
    Date of Patent: October 30, 2018
    Assignee: Maxlinear, Inc.
    Inventors: Curtis Ling, Anand Anandakumar, Ioannis Spyropoulos
  • Patent number: 10050710
    Abstract: Aspects of a method and system for feedback during optical communications are provided. In one embodiment, a system for optical communications comprises a digital-to-analog converter (DAC), a driver, and a transmit optical subsystem. The DAC is operable to receive a digital code of a plurality of digital codes and output an analog current signal having an analog current level of a plurality of analog current levels. The driver is operable to condition the analog current signal output from the digital-to-analog converter. The transmit optical subsystem is operable to generate an optical signal from the conditioned analog current signal. A digital modification of an input digital signal is dynamically controlled by a feedback path according to one or more characteristics of the optical signal. The one or more characteristics comprise a nonlinearity that may be temperature dependent.
    Type: Grant
    Filed: May 25, 2016
    Date of Patent: August 14, 2018
    Assignee: Maxlinear, Inc.
    Inventors: Anand Anandakumar, Ioannis Spyropoulos, Curtis Ling
  • Patent number: 10020886
    Abstract: The present invention relates in general to communication systems, and more specifically towards methods, systems, and devices that help improve transmission rates and spectral efficiency of intensity modulated (IM) or power modulated channels utilizing multi-level pulse amplitude modulation PAM-M. In an embodiment, the present invention used an iterative algorithm to open the eyes of an eye diagram in a relatively short number of steps. The algorithm, which may not require previous characterization of the channel, utilizes pseudo-random sequences, such as PSBS15 or PRQS10, and adaptive non-linear equalizers to optimize the pre-distortion taps.
    Type: Grant
    Filed: October 17, 2016
    Date of Patent: July 10, 2018
    Assignee: Panduit Corp.
    Inventors: Jose M. Castro, Richard J. Pimpinella, Brett Lane, Bulent Kose, Yu Huang
  • Patent number: 9853764
    Abstract: A method and an apparatus for self-calibration of an ONU receiver in a multi-wavelength PON system, said method including the initial physical layer scan of the receiver tuning range, distributed estimation of the down-stream wavelength channel drift with respect to the nominal standard-based wavelengths, and reporting the estimated downstream wavelength channel drift in the downstream Channel_Map message.
    Type: Grant
    Filed: March 24, 2014
    Date of Patent: December 26, 2017
    Assignees: ZTE Corporation, ZTE (USA) Inc.
    Inventors: Denis Andreyevich Khotimsky, DeZhi Zhang, ChangLei Li
  • Patent number: 9825708
    Abstract: A compensation apparatus and method for inter-channel nonlinear damage are disclosed where the apparatus includes: an iteration parameter determining unit configured to determine an iteration step of cross-phase modulation damage compensation performed in each channel in a multichannel optical fiber transmission link; an estimating unit configured to divide an optical fiber transmission link in each iteration step of each channel into one or more optical fiber segments, and perform cross-phase modulation damage estimation at a position in each optical fiber segment where the nonlinear damage is maximal; and a first compensating unit configured to perform cross-phase modulation damage compensation according to the result of the cross-phase modulation damage estimation.
    Type: Grant
    Filed: October 14, 2014
    Date of Patent: November 21, 2017
    Assignee: FUJITSU LIMITED
    Inventors: Yangyang Fan, Liang Dou, Zhenning Tao
  • Patent number: 9654314
    Abstract: A system for optimizing signal quality in an optical communication system is provided including a transmitter for converting digital signals to optical signals, the transmitter including a transmitter digital signal processing chip including a pre-distortion logic and a transmitter look-up table (LUT). A receiver is operatively coupled to the transmitter for receiving and converting the optical signals from the transmitter to digital signals. The receiver includes a receiver digital signal processing chip including a correction logic and a receiver look-up table (LUT). The transmitter LUT is constructed by scaling the receiver LUT by a weight factor and is iteratively updated based on a weighted sum of the receiver LUT.
    Type: Grant
    Filed: September 3, 2015
    Date of Patent: May 16, 2017
    Assignee: NEC Corporation
    Inventors: Fatih Yaman, Shaoliang Zhang, Yue-Kai Huang
  • Patent number: 9596035
    Abstract: A method of data symbol recovery. An optical signal is modulated by a transmitter using a modulation scheme comprising a symbol constellation having a predetermined asymmetry and detected at a receiver. Phase error estimates corresponding to data symbol estimates detected from the received optical signal are calculated. A phase rotation is calculated based on the phase error estimates, using a filter function, and the phase rotation applied to at least one data symbol estimate to generate a corresponding rotated symbol estimate. The phase error estimates model the asymmetry of the symbol constellation, such that the computed phase rotation can compensate phase noise that is greater than one decision region of the symbol constellation.
    Type: Grant
    Filed: November 29, 2012
    Date of Patent: March 14, 2017
    Assignee: Ciena Corporation
    Inventors: Shahab Oveis Gharan, Kim B. Roberts, Mahmoud Taherzadehboroujeni, Amir Khandani, Akbar Ghasemi
  • Patent number: 9584074
    Abstract: An optical receiver includes closed-loop composite second order (CSO) distortion correction logic. An optical communication system includes a transmitter comprising open-loop composite second order (CSO) distortion correction logic, and a receiver comprising closed-loop composite second order (CSO) distortion correction logic.
    Type: Grant
    Filed: February 13, 2009
    Date of Patent: February 28, 2017
    Assignee: ARRIS Enterprises, Inc.
    Inventors: Joseph F. Chiappetta, Marcel F. Schemmann
  • Patent number: 9553672
    Abstract: In an example, the present invention includes an integrated system on chip device. The device is configured on a single silicon substrate member. The device has a data input/output interface provided on the substrate member. The device has an input/output block provided on the substrate member and coupled to the data input/output interface. The device has a signal processing block provided on the substrate member and coupled to the input/output block. The device has a driver module provided on the substrate member and coupled to the signal processing block. In an example, the device has a driver interface provided on the substrate member and coupled to the driver module and configured to be coupled to a silicon photonics device. The device also has an interface configured to communicate between the silicon photonics device and the control block.
    Type: Grant
    Filed: September 16, 2016
    Date of Patent: January 24, 2017
    Assignee: INPHI CORPORATION
    Inventor: Radhakrishnan L. Nagarajan
  • Patent number: 9553677
    Abstract: Various technologies for continuous-variable quantum key distribution without transmitting a transmitter's local oscillator are described herein. A receiver on an optical transmission channel uses an oscillator signal generated by a light source at the receiver's location to perform interferometric detection on received signals. An optical reference pulse is sent by the transmitter on the transmission channel and the receiver computes a phase offset of the transmission based on quadrature measurements of the reference pulse. The receiver can then compensate for the phase offset between the transmitter's reference and the receiver's reference when measuring quadratures of received data pulses.
    Type: Grant
    Filed: November 17, 2015
    Date of Patent: January 24, 2017
    Assignee: Sandia Corporation
    Inventors: Daniel B. S. Soh, Mohan Sarovar, Ryan Camacho
  • Patent number: 9507082
    Abstract: Optical fibers Fp, Fn, included in a light transmission path, are two-mode optical fibers for propagating an LP01 mode component and an LP11 mode component contained in signal light, and a gradient d??/d? of a mode dispersion ?? with respect to a wavelength ? in a wavelength band of 1530 nm to 1625 nm is |0.5| ps/km/nm or less. Symbols of mode dispersions ?? of the optical fibers Fp, Fn are opposite to each other. The light transmission path can satisfactorily compensate the mode dispersion in a wide wavelength band.
    Type: Grant
    Filed: February 5, 2014
    Date of Patent: November 29, 2016
    Assignee: FUJIKURA LTD.
    Inventors: Ryo Maruyama, Nobuo Kuwaki, Shoichiro Matsuo
  • Patent number: 9479281
    Abstract: In an example, the present invention includes an integrated system on chip device. The device is configured on a single silicon substrate member. The device has a data input/output interface provided on the substrate member. The device has an input/output block provided on the substrate member and coupled to the data input/output interface. The device has a signal processing block provided on the substrate member and coupled to the input/output block. The device has a driver module provided on the substrate member and coupled to the signal processing block. In an example, the device has a driver interface provided on the substrate member and coupled to the driver module and configured to be coupled to a silicon photonics device. The device also has an interface configured to communicate between the silicon photonics device and the control block.
    Type: Grant
    Filed: May 19, 2016
    Date of Patent: October 25, 2016
    Assignee: INPHI CORPORATION
    Inventor: Radhakrishnan L. Nagarajan
  • Patent number: 9377579
    Abstract: A method of assessing the power penalty at a given bit error rate of a multimode fiber including measuring a set of elementary fiber responses corresponding to different offset launches of light over the core radius into the multimode fiber, generating a global fiber response by applying, to the set of elementary fiber responses, a set of weighting coefficients and delays depending on the different offset launches of the elementary fiber responses, and computing a parameter representative of a fiber power penalty from the global fiber response, wherein the set of weighting coefficients includes several subsets of weighting coefficients time delayed relative to one another, wherein at least one relative time delay is not set to zero, and wherein weighting coefficients of each subset depend on the different offset launches of the elementary fiber responses.
    Type: Grant
    Filed: October 16, 2012
    Date of Patent: June 28, 2016
    Assignee: DRAKA COMTEQ B.V.
    Inventors: Denis Molin, Pierre Sillard, Marianne Bigot-Astruc
  • Patent number: 9374173
    Abstract: In an example, the present invention includes an integrated system on chip device. The device is configured on a single silicon substrate member. The device has a data input/output interface provided on the substrate member. The device has an input/output block provided on the substrate member and coupled to the data input/output interface. The device has a signal processing block provided on the substrate member and coupled to the input/output block. The device has a driver module provided on the substrate member and coupled to the signal processing block. In an example, the device has a driver interface provided on the substrate member and coupled to the driver module and configured to be coupled to a silicon photonics device. The device also has an interface configured to communicate between the silicon photonics device and the control block.
    Type: Grant
    Filed: July 31, 2015
    Date of Patent: June 21, 2016
    Assignee: INPHI CORPORATION
    Inventor: Radhakrishnan L. Nagarajan
  • Patent number: 9363032
    Abstract: The present document relates to optical communication systems. In particular, the present document relates to high efficiency wavelength division multiplexing (WDM) optical communication systems. An optical transmitter (210) adapted to transmit an optical signal on an optical wavelength division multiplexed, referred to as WDM, transmission channel (111) to a corresponding optical receiver (230) is described.
    Type: Grant
    Filed: March 21, 2013
    Date of Patent: June 7, 2016
    Assignee: Alcatel Lucent
    Inventors: Jeremie Renaudier, Oriol Bertran-Pardo
  • Patent number: 9306700
    Abstract: Disclosed are a method and device for transmitting optical signals. The method comprises: if there is Raman crosstalk between a first optical network system and a coexistence system, an upstream wavelength band of the first optical network system is set outside a range with an upstream wavelength band of the coexistence system being a center and with an impact intensity of the Raman crosstalk being a radius, and a downstream wavelength band of the first optical network system is set outside a range with the downstream wavelength band of the coexistence system being a center and with the impact intensity of the Raman crosstalk being a radius; and optical signals are transmitted by using the upstream wavelength band of the first optical network system and the downstream wavelength band of the first optical network system. The disclosure can avoid interference and improve signal quality.
    Type: Grant
    Filed: June 29, 2012
    Date of Patent: April 5, 2016
    Assignee: ZTE CORPORATION
    Inventors: Songlin Zhu, Dan Geng, Zian He, Weiliang Zhang, Yongjia Yin, Yong Guo, Xingang Huang, Dezhi Zhang
  • Patent number: 9300401
    Abstract: The present invention provides an updating apparatus and method for an equalizer coefficient, receiver and optical communication system. The updating method comprises: receiving an optical signal transmitted by a transmitter in an optical communication system, the optical signal comprising transmission data and a constant modulus signal for updating a coefficient of an equalization filter; performing coherent detection and analog-to-digital conversion on the optical signal, so as to obtain a digital electric signal; and updating the coefficient of the equalization filter at a symbol corresponding to the constant modulus signal in the digital electric signal. With the embodiments of the present invention, not only the coefficients of the equalizer may be optimized, but also being adapted to signals in various modulation formats, and the complexity of the channel equalization may be lowered as well.
    Type: Grant
    Filed: September 13, 2013
    Date of Patent: March 29, 2016
    Assignee: FUJITSU LIMITED
    Inventors: Liang Dou, Zhenning Tao
  • Patent number: 9059806
    Abstract: An optical communication system, a transmission apparatus and a reception apparatus, and a transmission method and a reception method are provided. The transmission apparatus transmits an optical signal, and comprises: at least one encoder for encoding at least one data signal, respectively; at least one first modulator for performing first modulation on the at least one encoded data signal, respectively, and generating at least one first modulated signal; at least one second modulator for performing second modulation, which is DFT-spread-OFDM modulation, on the at least one first modulated signal, respectively, and generating at least one second modulated signal; and an up-converter for up-converting the at least one second modulated signal into the optical signal to be transmitted. Thus, a PAPR of the optical OFDM transmission signal is decreased, a signal distortion caused by non-linearity of optical devices is reduced, and a reception quality of the signal is improved.
    Type: Grant
    Filed: June 5, 2012
    Date of Patent: June 16, 2015
    Assignee: WUHAN RESEARCH INSTITUTE OF POSTS AND TELECOMMUNICATIONS
    Inventors: Qi Yang, Zhu Yang, Shaohua Yu
  • Patent number: 9037002
    Abstract: A pre-emphasis control method includes calculating an average value of transmission characteristics based on transmission characteristics of a plurality of light beams received by a receiver, and determining that, among signals of the plurality of light beams, a wavelength with a deviation from the average value is a wavelength at which control is to be performed, determining that the wavelength at which control is to be performed and a wavelength adjacent thereto are a group of wavelengths at which control is to be performed, obtaining an average of transmission characteristics of the group of wavelengths at which control is to be performed, and based on a difference between averaged transmission characteristics and respective transmission characteristics of the group of wavelengths at which control is to be performed, changing a light intensity output from each transmitter that transmits a group of wavelengths at which control is to be performed.
    Type: Grant
    Filed: November 10, 2011
    Date of Patent: May 19, 2015
    Assignee: FUJITSU LIMITED
    Inventors: Jyunji Tanaka, Shinichi Kaneko, Takeo Osaka
  • Patent number: 9036998
    Abstract: An undersea long-haul transmission system includes an optical fiber transmission span and a coherent detection and digital signal processing module for providing dispersion compensation. The transmission span includes at least one fiber pair comprising substantially equal lengths of a positive-dispersion first fiber and a negative-dispersion second fiber that are configured to provide a signal output at transmission distances greater than 10,000 km, in which the combined accumulated dispersion across the operating bandwidth does not exceed the dispersion-compensating capacity of the coherent detection and digital signal processing module. Further described is a fiber for use in an undersea long-haul transmission span. At a transmission wavelength of 1550 nm, the fiber has a dispersion coefficient in the range of ?16 to ?25 ps/nm·km, and a dispersion slope in the range of 0.04 to 0.02 ps/nm2·km.
    Type: Grant
    Filed: August 16, 2013
    Date of Patent: May 19, 2015
    Assignee: OFS FITEL, LLC
    Inventor: Ole A Levring
  • Patent number: 9031415
    Abstract: An Ethernet adapter system may include a transmitter to insert a payload type identifier sequence in a generic frame procedure header to indicate that a network is a converged enhanced Ethernet network. The transmitter may insert idle sequences in a stream of data frames transmitted along a link. The system may include a receiver to recognize a condition and to force a loss of synchronization condition on the link that will be converted by the receiver into a loss of light condition. The receiver may scan the transmitted stream of data frames for invalid data frames and introduce a code into the stream of data frames whenever an invalid data frame is detected.
    Type: Grant
    Filed: December 8, 2012
    Date of Patent: May 12, 2015
    Assignee: International Business Machines Corporation
    Inventors: Casimer M. DeCusatis, Thomas A. Gregg, Rajaram B. Krishnamurthy
  • Patent number: 9025962
    Abstract: A system for transmitting an optical signal between a host and a device according to a SATA protocol. The system comprises a transmitting-side converter for generating a logic one voltage value responsive to a data one value from an information source, for generating a logic zero voltage value responsive to a data zero value from the information source, for generating an idle state logic voltage value, wherein the idle state logic voltage value is (logic one voltage value+logic zero voltage value)/2, the transmitting-side converter comprising only linear functions to preserve the idle state logic voltage value, and an electrical-to-optical converter for converting the logic one, logic zero and the idle state logic voltage values to an optical signal further comprising respective logic one, logic zero and idle state optical values and for supplying the optical signal to an optical communications medium.
    Type: Grant
    Filed: January 28, 2013
    Date of Patent: May 5, 2015
    Inventor: James V Wernlund
  • Patent number: 9025965
    Abstract: Disclosed are a phase locked loop (PLL) of a digital scheme and a method thereof. More specifically, disclosed are a digital phase locked loop having a time-to-digital converter (TDC), a digital loop filter (DLF), and a digitally controlled oscillator (DCO), and that is designed to have a constant jitter characteristic at all times even though an operating condition of a circuit varies according to a process, voltage, temperature (PVT) change, and a method thereof.
    Type: Grant
    Filed: December 22, 2011
    Date of Patent: May 5, 2015
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Seung Woo Lee, Kwang Chun Choi, Woo Young Choi, Bhum Cheol Lee
  • Patent number: 9025651
    Abstract: Methods, systems, and devices are described for equalizing data from an optical signal. Samples are filtered with at least one filter to compensate for polarization mode dispersion in an optical path. The filtered samples may be used to determine errors based on a difference between a radius of a recovered symbol and a target radius. A parameter may be assigned to one or more of the errors and properties of the at least one filter may be updated based on the assigned parameters. The parameter may be assigned from a small set of parameters based on at least one threshold value. Outputs generated from the filtered samples may also be assigned a parameter from a different set of parameters. The parameter assigned to the output may be used to update the particular set of taps of the at least one filter from which the output was generated.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: May 5, 2015
    Assignee: ViaSat, Inc.
    Inventors: Sameep Dave, Fan Mo
  • Patent number: 9020365
    Abstract: Current optical networks are engineered to handle amplifier noise and chromatic dispersion. Polarization mode dispersion occurs in optical networks due splitting of the light energy of a pulse propagating in a fiber into two modes. Compensating for polarization mode dispersion is a difficult and expensive task and hence only few commercial systems have been deployed to deal with this issue. A polarization mode dispersion compensation module according to an example embodiment of the present invention compensates for polarization mode dispersion by determining a performance metric related to an error rate of an optical signal in at least one polarization mode in a filtered state. Based on the performance metric, a control vector is determined to control the optical signal in the at least one polarization mode in the filtered state. The control vector is then applied to a polarization effecting device to compensate for polarization mode dispersion.
    Type: Grant
    Filed: April 8, 2008
    Date of Patent: April 28, 2015
    Assignee: Tellabs Operations, Inc.
    Inventors: Richard C. Younce, Julia Y. Larikova
  • Patent number: 9014568
    Abstract: An optical access network with centralized digital optical line termination OLT including an optical line termination unit having a digital transmitter and a coherent receiver for downstream signal transmitting and upstream signal receiving, and at least one optical network unit ONU with transceiver functions for communicating with the OLT over an optical path, the ONU including intensity modulation and single photodiode detection, wherein the digital transmitter includes digital signal processing DSP, digital-to-analog conversion DAC and analog-to-digital conversion ADC functions that can be shared by all multiple ones of the ONU in the network, the DSP reducing or removing dispersion and non-linearity effects in the network and the coherent receiver enabling performance of the downstream stream signal transmitting to match that of the upstream signal receiving in the OLT.
    Type: Grant
    Filed: February 15, 2013
    Date of Patent: April 21, 2015
    Assignee: NEC Laboratories America, Inc.
    Inventors: Dayou Qian, Ting Wang
  • Publication number: 20150104190
    Abstract: A driving element which performs driving according to a level of a voltage signal to be transmitted optically, a modulation current driving circuit configured to supply a modulation current modulated by the driving element to a light source for optical communication configured to convert a current signal into light and to output the light, and a constant current supply circuit configured to supply a constant current to the light source for optical communication are included. Then, when the voltage signal is at a first level, the driving element is turned on and the modulation current driving circuit supplies the modulation current to the light source for optical communication. When the voltage signal is at a second level, the driving element is turned off and the modulation current driving circuit stops supplying the modulation current. The present technique can be applied, for example, to an optical transmission system.
    Type: Application
    Filed: September 11, 2014
    Publication date: April 16, 2015
    Inventors: Koki Uchino, Hideyuki Suzuki, Hiroshi Morita, Yoshifumi Miyajima, Masatsugu Sugano
  • Patent number: 9008514
    Abstract: Example embodiments of the present invention relate to An optical node comprising of at least two optical degrees; a plurality of directionless add/drop ports; and at least one wavelength equalizing array, wherein the at least one wavelength equalizing array is used to both select wavelengths for each degree, and to perform directionless steering for the add/drop ports.
    Type: Grant
    Filed: June 22, 2013
    Date of Patent: April 14, 2015
    Inventors: Mark E. Boduch, Kimon Papakos
  • Patent number: 9008518
    Abstract: A system includes an optical transmitter package comprising an optical transmitter to generate optical transmission signals based on electrical transmission signals. The system also includes an optical receiver package comprising an optical receiver to generate electrical reception signals based on optical reception signals. The system further includes a printed circuit board (PCB) on which the optical transmitter package and the optical receiver package are mounted. The PCB includes a heat generating circuit component. The optical transmitter package can be mounted to the PCB to subjected to less heat from the heat generating circuit component than the optical receiver package.
    Type: Grant
    Filed: January 30, 2013
    Date of Patent: April 14, 2015
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Michael Renne Ty Tan, Glenn C. Simon, Sagi Varghese Mathai
  • Publication number: 20150093119
    Abstract: System and method for equalizing a high bit rate optical communication channel in a symbol spaced adaptive Multiple-In-Multiple-Out (MIMO) system, where the optical communication channel carries a signal that is sampled at a symbol rate. Accordingly, Anti Aliasing Filtering (which introduces distortions in the form of Deterministic Inter Symbol Interference D-ISI) is applied in a MIMO channel, in order to reduce the aliasing effect associated with symbol rate sampling. The Polarization Mode Dispersions introduced in the optical communication channel are solely compensated by a MIMO Equalizer, which ignores the Deterministic ISI (D-ISI) distortion. Then the Deterministic ISI (D-ISI) distortion is solely compensated by an independent Deterministic Equalizer (DE).
    Type: Application
    Filed: January 2, 2013
    Publication date: April 2, 2015
    Inventors: Albert Gorshtein, Dan Sadot
  • Patent number: 8995845
    Abstract: A multi-laser transmitter optical subassembly may include N number of lasers, where each laser is configured to generate an optical signal with a unique wavelength. The transmitter optical subassembly may further include a focusing lens and a filter assembly. The filter assembly may combine the optical signals into a combined signal that is received by the focusing lens. The filter assembly may include N?1 number of filters. Each of the filters may pass at least one of the optical signals and reflect at least one of the optical signals. The filters may be low pass filters, high pass filters, or a combination thereof.
    Type: Grant
    Filed: January 9, 2012
    Date of Patent: March 31, 2015
    Assignee: Finisar Corporation
    Inventors: Tengda Du, Bernd Huebner
  • Patent number: 8989588
    Abstract: An optical transceiver includes an optical IC coupled to a processor IC. For transmit, the optical IC can be understood as a transmitter IC including a laser device or array. For receive, the optical IC can be understood as a receiver IC including a photodetector/photodiode device or array. For a transmitter IC, the processor IC includes a driver for a laser of the transmitter IC. The driver includes an equalizer that applies high frequency gain to a signal transmitted with the laser device. For a receiver IC, the processor IC includes a front end circuit to interface with a photodetector of the receiver IC. The front end circuit includes an equalizer that applies high frequency gain to a signal received by the receiver IC. The driver can be configurable to receive a laser having either orientation: ground termination or supply termination.
    Type: Grant
    Filed: January 22, 2013
    Date of Patent: March 24, 2015
    Assignee: Intel Corporation
    Inventors: Gil Afriat, Lior Horwitz, Dror Lazar, Assaf Issachar, Alexander Pogrebinsky, Adee O. Ran, Ehud Shoor, Roi Bar, Rushdy A. Saba
  • Patent number: 8971719
    Abstract: An optical system may have an optical transmitter including a digital signal processor to receive a signal channel, add data corresponding to a pilot tone, generate a digital signal associated with the signal channel and including the pilot tone, and output the digital signal. The optical system may further have a digital-to-analog converter to convert the digital signal to an analog signal, a laser to provide an optical signal, and a modulator to receive the optical signal and the analog signal, and modulate the optical signal based on the analog signal to form a modulated optical signal. The modulated optical signal may include the pilot tone. The optical system may also have an optical receiver to receive the modulated optical signal, process the modulated optical signal to determine a phase associated with the pilot tone, and apply the phase to the modulated optical signal to recover the signal channel.
    Type: Grant
    Filed: December 21, 2012
    Date of Patent: March 3, 2015
    Assignee: Infinera Corporation
    Inventors: Pierre Herve Mertz, David J. Krause, Han Henry Sun
  • Patent number: 8971703
    Abstract: A wavelength dispersion amount estimation method, a wavelength dispersion compensation circuit, and a receiving device which rapidly estimate and set a wavelength dispersion amount to compensate with high accuracy at the receiving device which compensates waveform distortion at an optical fiber transmission path.
    Type: Grant
    Filed: February 1, 2012
    Date of Patent: March 3, 2015
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Etsushi Yamazaki, Takayuki Kobayashi, Masahito Tomizawa, Riichi Kudo, Koichi Ishihara, Tadao Nakagawa, Mitsuteru Ishikawa
  • 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: 8958702
    Abstract: In accordance with the present disclosure, disadvantages and problems associated with polarization dependent effects of a polarization multiplexed optical signal may be reduced through polarization scrambling. In accordance with an embodiment of the present disclosure a method for detecting polarization scrambling of a polarization multiplexed optical signal comprises receiving a polarization multiplexed optical signal associated with an optical network. The polarization multiplexed optical signal including a scrambled polarization orientation, the polarization orientation scrambled according to a scrambling frequency. The method further comprising receiving a polarization signal indicating the polarization scrambling of the received optical signal. The method additionally comprises descrambling the optical signal according to the polarization scrambling as indicated by the polarization signal.
    Type: Grant
    Filed: March 17, 2011
    Date of Patent: February 17, 2015
    Assignee: Fujitsu Limited
    Inventor: Futoshi Izumi
  • Patent number: 8942574
    Abstract: A light receiving device includes: a converter digitalizing an analog signal with a given sampling clock frequency, the analog signal being obtained through a photoelectric conversion of a received optical signal; a plurality of fixed distortion compensators compensating an output signal of the converter for waveform distortion with a fixed compensation amount that is different from each other; a plurality of phase shift detector circuits detecting a sampling phase shift from an output signal of the plurality of the fixed distortion compensators; a phase-adjusting-amount determiner determining a sampling phase adjusting amount with use of an output signal of the plurality of the phase shift detector circuits; and a phase adjusting circuit reducing a phase difference between the sampling clock frequency and the received optical signal based on a determination result of the phase-adjusting-amount determiner.
    Type: Grant
    Filed: November 25, 2013
    Date of Patent: January 27, 2015
    Assignee: Fujitsu Limited
    Inventors: Hisao Nakashima, Takeshi Hoshida
  • Patent number: 8934786
    Abstract: An apparatus comprises an optical transmitter that comprises a processor and at least one optical modulator. The processor is configured to generate electronic representations of at least two pre-dispersion-compensated phase-conjugated optical variants carrying a same modulated payload data for transmission. The at least one optical modulator is configured to modulate the electronic representations, wherein an amount of dispersion induced on the pre-dispersion-compensated phase-conjugated optical variants depends on an accumulated dispersion (AD) of a transmission link through which the pre-dispersion-compensated phase-conjugated optical variants are to be transmitted. The amount of dispersion induced on the phase-conjugated optical variants may be approximately ?AD/2, where AD is the accumulated dispersion of the transmission link.
    Type: Grant
    Filed: August 31, 2012
    Date of Patent: January 13, 2015
    Assignee: Alcatel Lucent
    Inventors: Xiang Liu, Peter J. Winzer, Andrew Roman Chraplyvy, Robert William Tkach
  • Patent number: 8934782
    Abstract: A polarization state of a transmission signal can be changed at a high speed based on a symbol-rate By switching a first switch, a second switch, and a third switch with time, one of an X-polarized wave_I-signal as a Y-polarized wave_I-signal, a signal caused by performing logical inversion for an X-polarized wave_I-signal, an X-polarized wave_Q-signal and a signal caused by logical inversion for an X-polarized wave_Q-signal is input to a second modulator. Further, by switching the first switch, the second switch and the third switch with time, the second modulator is input one of the X-polarized wave_I-signal as the Y-polarized wave_Q-signal, the X-polarized wave_I-signal, the signal caused by performing logical inversion for the X-polarized wave_I-signal, the X-polarized wave_Q-signal and the signal caused by performing logical inversion for the X-polarized wave_Q-signal. Thereby, a polarization state of a transmission signal can be changed at high speed based on a symbol-rate speed.
    Type: Grant
    Filed: February 3, 2011
    Date of Patent: January 13, 2015
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Tadao Nakagawa, Etsushi Yamazaki, Koichi Ishihara, Takayuki Kobayashi, Riichi Kudo, Yasushi Takatori, Munehiro Matsui, Yutaka Miyamoto, Akihide Sano, Eiji Yoshida, Masato Mizoguchi
  • Patent number: 8934783
    Abstract: An Ethernet adapter system may include a transmitter to insert a payload type identifier sequence in a generic frame procedure header to indicate that a network is a converged enhanced Ethernet network. The transmitter may insert idle sequences in a stream of data frames transmitted along a link. The system may include a receiver to recognize a condition and to force a loss of synchronization condition on the link that will be converted by the receiver into a loss of light condition. The receiver may scan the transmitted stream of data frames for invalid data frames and introduce a code into the stream of data frames whenever an invalid data frame is detected.
    Type: Grant
    Filed: February 17, 2011
    Date of Patent: January 13, 2015
    Assignee: International Business Machines Corporation
    Inventors: Casimer M. DeCusatis, Thomas A. Gregg, Rajaram B. Krishnamurthy
  • Patent number: 8934777
    Abstract: According to one embodiment of a method for interference suppression in radio-over-fiber communication systems, the method uses a mode selection module to continuously update real time information of at least two mobile stations and determine to enter a cross mode or a single mode. In the single mode, when a mobile station approaches a switching point, a single mode command is issued to control at least one first specific remote antenna unit (RAU). In the cross mode, when an immediate cross condition is a new cross condition, a new cross mode table is generated, and when the position of any one mobile station of the at least two mobile stations cross a threshold, a cross mode command is issued to control at least one second specific RAU according to a corresponding cross mode table.
    Type: Grant
    Filed: February 8, 2013
    Date of Patent: January 13, 2015
    Assignee: Industrial Technology Research Institute
    Inventors: Hsien-Wen Chang, Ming-Chien Tseng, Ming-Hung Cheng
  • Patent number: 8929747
    Abstract: A transmitter reduces or minimizes pulse narrowing. In one approach, an optical transmitter is designed to transmit data over an optical fiber at a specified data rate using on-off keying. The transmitter includes a pre-converter electrical channel and a limiting E/O converter. The pre-converter electrical channel produces a pre-converter signal that drives the limiting E/O converter. The pre-converter electrical channel is designed to reduce pulse narrowing in the pre-converter signal. In one implementation, the pre-converter electrical channel includes a pre-emphasis filter that is designed to minimize pulse width shrinkage.
    Type: Grant
    Filed: July 23, 2012
    Date of Patent: January 6, 2015
    Assignee: ClariPhy Communications, Inc.
    Inventor: Thomas A. Lindsay
  • Publication number: 20140369694
    Abstract: Communication transmission system and method are disclosed based on introducing a large pre-dispersion of optical signal before launching the signal into an uncompensated communication system. The pre-dispersion has the same sign as dispersion of a transmission fibre. The aim of the method is to improve the transmission quality and simplify the digital signal mitigation of nonlinear impairments after the transmission. In the preferred embodiment, the optical system is a coherent communications system with any symbol rate, modulation format and/or carrier wavelength.
    Type: Application
    Filed: June 14, 2013
    Publication date: December 18, 2014
    Inventors: Sergei Turitsyn, Mariia Sorokina
  • Patent number: 8913901
    Abstract: A system and method for blind equalization of a QAM signal. Equalization is achieved using an algorithm characterized by cost function that is a function the Euclidian distance, e.g. the minimum Euclidian distance, between points of the constellation associated with the QAM signal, i.e. the distance between symbols.
    Type: Grant
    Filed: August 8, 2012
    Date of Patent: December 16, 2014
    Assignee: Tyco Electronics Subsea Communications LLC
    Inventors: Hongbin Zhang, Yu Sun, Alexei N. Pilipetskii
  • Patent number: 8909069
    Abstract: A method and system for a estimating a most likely location of a periodic SYNC burst within an optical signal received through an optical communications system. A cross-correlation is calculated between a multi-bit digital signal derived from the optical signal and a known symbol sequence of the SYNC burst. The cross-correlation is processed in at least one sub-block to identify a candidate sub-block in which the SYNC burst is most likely located. The candidate sub-block is then further analyzed to estimate a location of the SYCN burst.
    Type: Grant
    Filed: May 21, 2013
    Date of Patent: December 9, 2014
    Assignee: Ciena Corporation
    Inventor: Kim B. Roberts
  • Patent number: 8909060
    Abstract: An optical communication system in which optical transmitter 101 that modulates an electric signal to an optical signal and transmits the optical signal and optical receiver 108 that receives the optical signal are connected via transmission path 107, wherein, when a change in the dispersion amount of chromatic dispersion caused by the optical signal passing through transmission path 107 is nearly eliminated, optical transmitter 101 and optical receiver 108 decrease the absolute value of a receiver-side dispersion compensation amount while keeping the total value of a transmitter-side dispersion compensation amount for compensating for the dispersion amount by optical transmitter 101 and the receiver-side dispersion compensation amount for compensating for the dispersion amount by optical receiver 108 substantially constant.
    Type: Grant
    Filed: January 8, 2010
    Date of Patent: December 9, 2014
    Assignee: NEC Corporation
    Inventor: Kiyoshi Fukuchi
  • Patent number: 8909061
    Abstract: A method is provided for performing chromatic dispersion (CD) pre-compensation. The method generates an electronic signal at a transmitter, and uses a transmit CD compensation estimate to compute a CD pre-compensation filter. The transmit CD pre-compensation filter is used to process the electronic signal, generating a pre-compensated electronic signal. The pre-compensated electronic signal is converted into an optical signal and transmitted to an optical receiver via an optical channel. In one aspect, the transmitter generates a test electronic signal and the CD compensation estimate uses a first dispersion value to compute a first CD compensation filter. The transmitter accepts a residual dispersion estimate of the test optical signal from the first optical receiver CD compensation filter, generated from a (receiver-side) CD estimate, and then the transmit CD estimate can be modified in response to the combination of the first dispersion value and residual dispersion estimate.
    Type: Grant
    Filed: May 2, 2012
    Date of Patent: December 9, 2014
    Assignee: Applied Micro Circuits Corporation
    Inventor: Badri Varadarajan
  • Patent number: 8903249
    Abstract: A method and apparatus for suppressing pump-mode optical beat interference noise in a Raman amplified fiber link of an optical network, wherein a wavelength of a laser beam generated by a first pump laser and a wavelength of a laser beam generated by a second pump laser of a pair of polarization multiplexed pump lasers are detuned with respect to each other to suppress the optical beat interference, OBI, noise in the Raman amplified fiber link of said optical network.
    Type: Grant
    Filed: August 31, 2012
    Date of Patent: December 2, 2014
    Assignee: ADVA Optical Networking SE
    Inventor: Dogan Atlas
  • Patent number: 8897646
    Abstract: An optical add/drop multiplexer including one or more optical drop multiplexers connected in free space or fused by optical fiber pigtails, a wavelength blocker with an input port connected to an output port of the optical drop multiplexer through the fusion of the fiber pigtails, one or more optical add multiplexers connected in free space or fused by fiber pigtails, a digital signal processor, an analog-to-digital signal converter, a digital-to-analog converter, and a plurality of electronic control and feedback loops for tuning and scanning an optical wavelength.
    Type: Grant
    Filed: September 29, 2012
    Date of Patent: November 25, 2014
    Assignee: GP Photonics, Inc.
    Inventor: Peiliang Gao