Including Postcompensation Patents (Class 398/208)
  • Patent number: 8861981
    Abstract: Embodiments of the present invention disclose an optical signal compensation device, where, a nonlinear compensation module in the optical signal compensation device adopts a new nonlinear compensation algorithm to perform nonlinear compensation on an optical signal, and during the process of performing the nonlinear compensation, it is no longer required to look up a table. Technical solutions provided in the embodiments of the present invention can effectively increase the processing speed of the nonlinear compensation, thereby reducing the overall processing delay of an optical signal compensation system.
    Type: Grant
    Filed: March 18, 2013
    Date of Patent: October 14, 2014
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Ling Liu, Liangchuan Li
  • Patent number: 8855503
    Abstract: Optical receiver 300 uses two optical delay detectors 223 (set such that the delay times T are equal to symbol time and the phase differences are zero and 90 degrees) to receive an optical multilevel signal 215 and the output signals are A/D converted, thereafter subjected to retiming processes, and then subjected to a differential phase detection, thereby detecting a differential phase at a symbol center time point. In the receiver, the detected differential phase is integrated for each symbol and thereafter combined with an amplitude component obtained from a separately disposed optical intensity receiver, thereby reproducing an optical electric field. Thereafter, a wavelength dispersion compensation circuit (231) of a time period T is used to compensate for the wavelength dispersion of the transmission path. Moreover, an electric or optical Nyquist filter may be inserted to perform a band limitation, thereby enhancing the wavelength dispersion compensation effect.
    Type: Grant
    Filed: July 9, 2010
    Date of Patent: October 7, 2014
    Assignee: Hitachi, Ltd.
    Inventor: Nobuhiko Kikuchi
  • Patent number: 8855504
    Abstract: An optical receiver has an adaptive optical compensator and/or an adaptive electrical equalizer for compensating signal distortion in a received optical signal. In order to achieve a very fast adaptation of the receiver to the actual signal distortion, which is important for example for bursts mode optical signals in a packet-switched optical transmission network, at least one predetermined trainings sequence is provided in the optical signal, which is known at the receiver and thus enables fast adaptation of the compensator and/or equalizer to the actual signal distortion.
    Type: Grant
    Filed: June 23, 2004
    Date of Patent: October 7, 2014
    Assignee: Alcatel Lucent
    Inventor: Henning Bülow
  • Patent number: 8849131
    Abstract: Polarization scattering compensation device and method are disclosed. In the device, a time sequence alignment unit aligns time sequences of signals in the first and second polarization state transmitted simultaneously; a polarization scattering estimation unit estimates a scattering coefficient of a scattering by the signal in the first polarization state on the signal in the second polarization state, and a scattering coefficient of a scattering by the signal in the second polarization state on the signal in the first polarization state; and a polarization scattering removal unit removes the scattering by the signal in the first polarization state on the signal in the second polarization state, and the scattering by the signal in the second polarization state on the signal in the first polarization state, in accordance with the scattering coefficients.
    Type: Grant
    Filed: April 27, 2012
    Date of Patent: September 30, 2014
    Assignee: Fujitsu Limited
    Inventors: Lei Li, Zhenning Tao, Shoichiro Oda
  • Publication number: 20140286650
    Abstract: An optical receiver includes: a frontend circuit configured to generate a baseband signal representing a received optical signal by using local oscillator light; a frequency offset estimator configured to estimate a frequency offset of the baseband signal; a frequency offset corrector configured to correct the frequency offset of the baseband signal according to an estimation result by the frequency offset estimator; a phase recovery configured to recover a modulated phase from the baseband signal for which the frequency offset is corrected; a data recovery configured to recover transmission data according to the modulated phase recovered by the phase recovery; and a controller configured to control an operation of the frequency offset estimator according to a phase error of the baseband signal for which the frequency offset is corrected.
    Type: Application
    Filed: February 21, 2014
    Publication date: September 25, 2014
    Applicant: FUJITSU LIMITED
    Inventor: Hiroshi Ogiwara
  • Publication number: 20140286651
    Abstract: An optical receiver for coherent optical communication, includes: a splitting element that splits a signal light into two optical axes; optical hybrids each of which is coupled with the two split optical axes; a skew adjustment element that is arranged on one of the optical axes, and adjusts a difference between optical path lengths of the two optical axes between the splitting element and the optical hybrids; a carrier; an adhesive that is filled between the skew adjustment element and the carrier; and a void that is located at an end portion of an optical axis direction of the skew adjustment element in a region where the skew adjustment element and the carrier are opposed to each other, the void being not filled up with the adhesive.
    Type: Application
    Filed: March 20, 2014
    Publication date: September 25, 2014
    Applicant: Sumitomo Electric Industries, Ltd.
    Inventor: Masaru TAKECHI
  • Patent number: 8842992
    Abstract: A communications device includes a transmitter device having an optical source configured to generate an optical carrier signal, a first E/O modulator coupled to the optical source and configured to modulate the optical carrier signal with an input signal having a first frequency, and a second E/O modulator coupled to the optical source and configured to modulate the optical carrier signal with a reference signal. The communications device includes an optical waveguide coupled to the transmitter device, and a receiver device coupled to the optical waveguide and including an O/E converter coupled to the optical waveguide and configured to generate an output signal comprising a replica of the input signal at a second frequency based upon the reference signal.
    Type: Grant
    Filed: March 7, 2012
    Date of Patent: September 23, 2014
    Assignee: Harris Corporation
    Inventors: Charles Middleton, Richard DeSalvo, Peter S. Scheuter
  • Publication number: 20140270809
    Abstract: A coherent optical receiver according to an exemplary aspect of the invention includes a coherent optical receiving part performing coherent detection by inputting and mixing local oscillation light and main signal light received through a transmission line with a signal applied at a transmitting side, outputting the signal applied to the main signal light as an electric signal, and regenerating and outputting an original signal on the basis of the electric signal; and a local oscillation optical frequency control part receiving channel information on a transmission line adjacent to the main signal light, and outputting the local oscillation light after changing a frequency of the local oscillation light depending on the presence or absence of adjacent channel signal light of other signal light in an adjacent channel.
    Type: Application
    Filed: March 18, 2013
    Publication date: September 18, 2014
    Inventor: Makoto SHIBUTANI
  • Publication number: 20140270810
    Abstract: Provided is a frequency error estimating apparatus used for a coherent optical receiver, which determines an amplitude of a baseband digital electrical signal converted from a received light signal modulated with a phase and amplitude shift keying, determines, with respect to each determined amplitude, a modulated phase component of the baseband digital electrical signal based on phase noise estimation values and frequency error estimation values of N previous symbols (N is a positive integer), and calculates a frequency error based on an inter-symbol phase difference of a signal obtained by cancelling the modulated phase component from the baseband digital electrical signal.
    Type: Application
    Filed: January 30, 2014
    Publication date: September 18, 2014
    Applicant: FUJITSU LIMITED
    Inventor: Hisao Nakashima
  • 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: 8837957
    Abstract: An apparatus comprising a frequency-domain equalizer that has been iteratively generated to compensate for filtering effects of a wavelength selective switch, wherein the FDEQ is configured to process in a frequency domain digital samples of a polarization multiplexed phase-shift-keying signal that has been transported over an optical channel.
    Type: Grant
    Filed: January 12, 2012
    Date of Patent: September 16, 2014
    Assignee: Futurewei Technologies, Inc.
    Inventors: Zhuhong Zhang, Yanming Li, Chuandong Li, Fei Zhu
  • Publication number: 20140255042
    Abstract: An optical receiver is disclosed having a dielectric non-conductive substrate. A ground plane is positioned on the dielectric non-conductive substrate. An optical signal converting photodiode is also positioned on the dielectric non-conductive substrate, and has an optical signal receiver and an electrical signal output. An electrical signal amplifier is provided having an input connected to the electrical signal output of the optical signal converting photodiode. A first opening is positioned in the ground plane and surrounds the optical signal converting photodiode. The first opening has a resonance frequency higher than a fundamental frequency such that crosstalk is reducible at the input of the electrical signal amplifier.
    Type: Application
    Filed: March 7, 2014
    Publication date: September 11, 2014
    Applicant: TYCO ELECTRONICS SVENSKA HOLDINGS AB
    Inventors: Andrei Kaikkonen, Lennart Per Olof Lundqvist, Lars-Goete Svensson, Peter Lindberg
  • Patent number: 8824898
    Abstract: For providing circuit arrangement and method for transmitting signals from a data source to a data sink, the signals being TMDS encoded, the driver circuit is supplied by a connection interface, connected upstream, assigned to data source, with supply voltage, electrical TMDS encoded signals are electro-optically converted by an LED connected downstream of the driver circuit and coupled into an optical fiber as light supplied with TMDS encoded signals, the direct current portion supplied from TMDS transmitter to connection interface, to data source, is converted by driver circuit to a modulated signal current for controlling LED.
    Type: Grant
    Filed: April 8, 2011
    Date of Patent: September 2, 2014
    Assignee: SILICON LINE GmbH
    Inventors: Martin Groepl, Holger Hoeltke
  • Patent number: 8818209
    Abstract: A frequency decimation block for processing an analog input signal including a high-bandwidth data signal to generate a parallel set of parallel output signals, in which each output signal represents a respective portion of the high-bandwidth data signal. A preamplifier is provided for amplifying the input signal. A frequency domain divider divides the amplified input signal to generate a set of frequency band signals including a low frequency band signal, a mid-frequency band signal, and a high frequency band signal. Each frequency band signal is supplied to at least one signal path. A respective non-linear processor is connected in each of M signal paths processes the input signal using a respective branch signal to yield a corresponding composite signal. A respective Low-Pass Filter (LPF) is connected in each signal path, for low-pass filtering at least the composite signals to generate corresponding ones of the parallel output signals.
    Type: Grant
    Filed: June 19, 2012
    Date of Patent: August 26, 2014
    Assignee: Ciena Corporation
    Inventors: William Martin Snelgrove, Kim B. Roberts, Bertram Leesti, Shahab Oveis Gharan, Mahmoud Taherzadehboroujeni
  • Publication number: 20140233966
    Abstract: Systems, devices and techniques for processing received QPSK modulated optical signals include sampling the received signal at twice the baud rate, thereby producing samples that are then processed as 9-QAM symbols using a decision directed least squares optimization method. Data bits are then recovered from the resulting symbol estimates. The received optical signal may also include dual polarized signals for increased bandwidth capacity.
    Type: Application
    Filed: December 22, 2013
    Publication date: August 21, 2014
    Applicant: ZTE (USA) INC.
    Inventors: Jianjun Yu, Bo Huang
  • Patent number: 8811829
    Abstract: A photon detection system including a photon detector configured to detect single photons, the photon detector being gated such that it produces a periodic output signal and the gating signal having a frequency of at least 50 MHz. The system further includes a combiner for combining the signal from one period with signals from other periods such that periodic variations in the output signal of the detector are suppressed.
    Type: Grant
    Filed: March 15, 2012
    Date of Patent: August 19, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Zhiliang Yuan, Andrew James Shields
  • Patent number: 8805208
    Abstract: A system and method for polarization de-multiplexing in a coherent optical receiver. De-multiplexing is achieved using a modified constant modulus algorithm (CMA) wherein filter coefficients are determined as a function of a coupling coefficient to avoid convergence of the CMA outputs.
    Type: Grant
    Filed: February 3, 2012
    Date of Patent: August 12, 2014
    Assignee: Tyco Electronics Subsea Communications LLC
    Inventors: Hongbin Zhang, Oleg Sinkin
  • Patent number: 8805198
    Abstract: An optical transmission and reception system in which a plurality of tributary signals are converted into multilevel modulated light for transmission and reception. An apparatus for transmitting multilevel modulated light includes: FECs which perform error correction processing including addition of a tributary identifier; and a GEAR BOX which performs rate conversion on the processed signals.
    Type: Grant
    Filed: April 13, 2009
    Date of Patent: August 12, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventor: Takashi Mizuochi
  • Patent number: 8805209
    Abstract: In one embodiment, a method for performing nonlinearity compensation on a dispersion-managed optical signal that was transmitted over an optical communication link, the method including virtually dividing the communication link into a plurality of steps, performing lumped dispersion compensation on a received optical signal to obtain a waveform upon which digital backward propagation (DBP) can be performed, performing DBP by performing dispersion compensation and nonlinearity compensation for each step, and generating an estimate of the transmitted signal based upon the performed DBP.
    Type: Grant
    Filed: February 24, 2012
    Date of Patent: August 12, 2014
    Inventors: Guifang Li, Likai Zhu
  • Publication number: 20140219666
    Abstract: A receiver and a multi-symbol-differential-detection (MSDD) module, the MSDD may include an input node for receiving an input signal having a noisy phase; a summation and rotation unit; and an output unit; wherein the output unit is arranged to output an output signal and a normalized output signal; wherein the output signal represents the input signal but has a reconstructed phase; wherein the summation and rotation unit is arranged to receive the input signal and the output signal and to provide a reference signal that reflects a weighted sum of phase rotated and delayed previously received input signals; wherein the output unit comprises a phase difference calculator, a slicer, a delay unit and a normalizer; wherein the phase difference calculator is arranged to generate a difference signal indicative of a phase difference between the reference signal and the input signal; wherein the slicer and the delay unit are arranged to generate the output signal by slicing the difference signal to provide a sliced s
    Type: Application
    Filed: March 1, 2012
    Publication date: August 7, 2014
    Applicant: Technion Research and Development Foundation LTD.
    Inventors: Igor Tselniker, Netta Sigron, Moshe Nazarathy
  • Patent number: 8798483
    Abstract: The present invention discloses an apparatus and method for adaptive dispersion compensation, the apparatus comprising: a coarse-grain tunable dispersion compensator, a receiver with electric adaptive dispersion compensator, and a control logic unit. In the method, firstly it is to perform optical dispersion compensation for the input optical signals; then to perform electric dispersion compensation for the optical signals for which the optical dispersion compensation is performed; it is to detect the performance parameters of the receiving of the optical signals for which the electric dispersion compensation has been performed, and based on the performance parameters, it is to perform optical dispersion compensation adjustment for said input optical signals. With an optical de-multiplexer further, said apparatus can perform adaptive dispersion compensation for the multi-channel system.
    Type: Grant
    Filed: December 20, 2005
    Date of Patent: August 5, 2014
    Assignee: ZTE Corporation
    Inventor: Huade Shu
  • Patent number: 8792789
    Abstract: A method is provided for performing chromatic dispersion (CD) compensation. A zero-forcing filter is calculated with a number of taps (n) required to nullify a chromatic dispersion frequency response of an optical channel. The number of taps in the zero-forcing filter is truncated to a number equal to (n?x), where x is an integer greater than 0. In one aspect, the chromatic dispersion frequency response of the optical channel is partitioned into a plurality of constituent chromatic dispersion responses, and a zero-forcing filter is calculated for each of the plurality of constituent chromatic dispersion responses. The number of taps in each of the plurality of zero-forcing filters is truncated, and the CD compensation filter is formed for each of the plurality of truncated tap zero-forcing filters. In another aspect, the tap values of the zero-forcing filter are quantized to a finite quantization set.
    Type: Grant
    Filed: March 7, 2012
    Date of Patent: July 29, 2014
    Assignee: Applied Micro Circuits Corporation
    Inventors: Badri Varadarajan, Daruish Dabiri, Subhash Roy
  • Patent number: 8792785
    Abstract: A circuit for monitoring an optical receiver or transceiver, architectures, circuits, and systems including the same, and a method for monitoring received optical power are disclosed. The receiver monitoring circuit comprises an avalanche photodiode (APD), a microprocessor, and first and second transresistance amplifiers. The microprocessor is configured to supply bias voltage to the APD. Photocurrent produced by the APD is supplied to the first and second transresistance amplifiers, and then the microprocessor captures optical power from the voltage signal of the first and second transresistance amplifiers.
    Type: Grant
    Filed: May 23, 2012
    Date of Patent: July 29, 2014
    Assignee: Source Photonics, Inc.
    Inventors: Xu Jiang, Xin Shuai, Bing Ju, Yi Yang
  • Patent number: 8787776
    Abstract: An optical receiver includes a photodetector for detecting incoming optical data signals and an amplifier for providing signal gain and current to voltage conversion. The detection signal generated by the photodetector may include a distortion component caused by an operating characteristic of the photodetector. A signal compensating circuit may reconstruct the received optical data signal by effectively canceling the distortion component. For this purpose, the signal compensating circuit may include a decision feedback equalizer implemented using at least one feedback filter matched to the operating characteristic of the photodetector causing the signal distortion so as to reproduce the distortion component for cancellation. Use of a control module may also configure the optical receiver in real time to account for other operating and environmental conditions of the optical receiver.
    Type: Grant
    Filed: June 3, 2011
    Date of Patent: July 22, 2014
    Assignee: The Governing Council of the University of Toronto
    Inventors: Anthony Chan Carusone, Tony Shuo-Chun Kao, Hemesh Yasotharan
  • Patent number: 8787769
    Abstract: In order to compensate for chromatic dispersion caused by optical fiber transmission in a communication system with coherent detection using optical signals, specific frequency band signals are used to enable estimation of a chromatic dispersion value.
    Type: Grant
    Filed: July 14, 2010
    Date of Patent: July 22, 2014
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Koichi Ishihara, Takayuki Kobayashi, Riichi Kudo, Yasushi Takatori, Munehiro Matsui, Masato Mizoguchi, Tadao Nakagawa, Etsushi Yamazaki, Akihide Sano, Yutaka Miyamoto, Eiji Yoshida, Shogo Yamanaka
  • 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: 8768173
    Abstract: An optical receiver includes: a first generator to generate, from an optical signal to which a reference signal is inserted, a first digital signal representing a signal component of a first partial band including the reference signal, using a first local oscillation light of a first frequency; a second generator to generate, from the optical signal, a second digital signal representing a signal component of a second partial band including the reference signal, using a second local oscillation light of a second frequency being different from the first frequency; a frequency compensator to adjust a frequency of the signal component of the first partial band and a frequency of the signal component of the second partial band according to a frequency of the reference signal; and a combiner to combine the first and second partial bands adjusted by the frequency compensator.
    Type: Grant
    Filed: December 13, 2011
    Date of Patent: July 1, 2014
    Assignee: Fujitsu Limited
    Inventors: Takahito Tanimura, Takeshi Hoshida
  • Patent number: 8768181
    Abstract: A differential code optical transmission and reception device including: a digital signal processing optical transceiver that converts information data into an optical signal and transmits it to a communication channel, a reception front end part that receives the optical signal from the communication channel, an O/E conversion part that converts the optical signal received from the communication channel into an electrical signal, a skew correction part that regulates or correct a skew between lanes contained in the electrical signal, a differential decoder that decodes a differential code of the skew corrected electrical signal, and a lane exchange/rotation part that rearranges the electrical signal having passed through the differential decoder into a lane state thereof at the time of transmission in cases where lane exchange has occurred in the communication channel.
    Type: Grant
    Filed: October 6, 2010
    Date of Patent: July 1, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kiyoshi Onohara, Hideo Yoshida, Takashi Sugihara
  • Patent number: 8761614
    Abstract: A coherent optical receiver Includes an electro-optic module coupled to an electronic signal processing Integrated circuit (IC) via a parallel analog transmission line bus. The electro-optic module receives and detects an optical channel light including a high-bandwidth signal modulated thereon. The electro-optic module includes: a single optical hybrid for mixing the optical channel light with a corresponding continuous wave local oscillator light to generate a mixed light containing the high-bandwidth data signal, at least one photodetector; and an analog frequency decimator for generating a set of parallel analog signals, each analog signal representing a respective portion of the high-bandwidth signal.
    Type: Grant
    Filed: June 14, 2011
    Date of Patent: June 24, 2014
    Assignee: Ciena Corporation
    Inventors: Yuriy Greshishchev, Ian Betty, Kim B. Roberts
  • Patent number: 8761609
    Abstract: A receiver for fiber optic communications.
    Type: Grant
    Filed: November 2, 2010
    Date of Patent: June 24, 2014
    Assignee: ClariPhy Communications, Inc.
    Inventors: Oscar E. Agazzi, Diego E. Crivelli, Hugo S. Carrer, Mario R. Hueda, Martin I. del Barco, Pablo Gianni, Ariel Pola, Elvio Serrano, Alfredo Taddei, Alejandro Castrillon, Martin Serra, Ramiro Matteoda
  • Publication number: 20140169797
    Abstract: Embodiments are provided for transmitting channel information, such as control channel information, using lower resources at the transmitter combined with using apriori information associated with channel information in the decoder of the receiver. The apriori information represent predictable information that can be predicted by the receiver and is not transmitted with the channel information by the transmitter. The transmitter determines the apriori information for the channel and codes the channel information into bits and fields excluding the apriori information. Upon receiving the channel information, the receiver determines the apriori information associated in accordance with previously received information. The apriori information is then provided as probability information for input to the decoder. The decoder then decodes the received information in accordance with the apriori information.
    Type: Application
    Filed: December 18, 2013
    Publication date: June 19, 2014
    Inventors: Aaron Callard, Mohammadhadi Baligh, Kelvin Kar Kin Au
  • Patent number: 8755696
    Abstract: A control apparatus for controlling an optical receiver having delay paths comprises an optical variable attenuator configured to generate a variable signal and provide the variable signal to the optical receiver; a fine control voltage controller configured to generate a variable fine control voltage and input the variable fine control voltage to one path of the delay paths of the optical receiver; a photo-diode voltage monitor configured to detect a first voltage value and a second voltage value; a bit error rate (BER) checker configured to estimate a bit error rate (BER) according to a signal output from the optical receiver; and a controller configured to set a value of the variable signal and a value of the variable fine control voltage and to estimate the fine control voltage that makes the bit error rate a minimum according to the first voltage value and the second voltage value.
    Type: Grant
    Filed: May 30, 2012
    Date of Patent: June 17, 2014
    Assignee: Electronics and Telecommunications Research Institute
    Inventor: Jyung-Chan Lee
  • Patent number: 8755695
    Abstract: A burst transmission method and a receiver resetting method and apparatus in a Passive Optical Network (PON) are provided. A burst receiver resetting method in a PON includes: receiving a preamble sequence and synchronizing data; after synchronizing the data, continuing to receive the data, and matching a Burst Terminator (BT); and resetting a receiver after successfully matching the BT. Meanwhile, an apparatus for implementing the method and a corresponding burst data transmission method are provided. By using the burst receiver resetting method and apparatus in the PON and the corresponding burst transmission method at an Optical Network Unit (ONU) burst transmission end, a Reach Extender (RE) does not need to unpack upstream burst bandwidth allocation information carried in downstream data.
    Type: Grant
    Filed: September 25, 2013
    Date of Patent: June 17, 2014
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Jing Li, Dongning Feng, Dongyu Geng, Frank Effenberger
  • Publication number: 20140161470
    Abstract: Compensation for in-phase (I) and quadrature (Q) timing skew and offset in an optical signal may be achieved based on the correlation between derivatives of I and Q samples in the optical signal. The magnitude of the correlation between derivatives is measured to determine the presence of skew. Correlation between derivatives may be coupled with frequency offset information and/or with trials having additional positive and negative skew to determine presence of skew. Correlations are determined according to pre-defined time periods to provide for continued tracking and compensation for timing skew that may result from, for example, thermal drift.
    Type: Application
    Filed: February 12, 2014
    Publication date: June 12, 2014
    Applicant: ViaSat, Inc.
    Inventors: Yuri Zelensky, Fan Mo
  • Publication number: 20140161442
    Abstract: The present invention relates to a fiber transmission field and provides a data sending or receiving method, device, and apparatus used in optical fiber transmission. The method includes: detecting data to be transmitted; encoding one bit pulse width to M parts if the to-be-transmitted data is 0, wherein the first part is a high-level, the later M?1 part is a low-level; encoding one bit pulse width to N parts if the to-be-transmitted data is 1, wherein the first part is a high level, and the later N?1 part is a low-level, the M is not equal to the N but both are integer which is greater than or equal to 2; and sending the encoded level signal.
    Type: Application
    Filed: August 8, 2012
    Publication date: June 12, 2014
    Applicant: AEROSPACE SCIENCE & INDUSTRY SHENZHEN (GROUP) CO., LTD.
    Inventors: Jun Yang, Lin Cheng
  • Patent number: 8750725
    Abstract: A digital optical receiving module including: an optical input, a first digital electrical output, an optoelectronic transducer device which converts a modulated optical signal, which is applied to the optical input, to an analog electrical signal, a decision-making device, which is electrically connected to the transducer device and converts the analog electrical signal to a digital signal and passes this digital signal to the digital electrical output, and a quality recording device, which is connected to the transducer device and determines the quality of the analog electrical signal before it is converted to a digital signal, with an information signal being produced as a function of the quality of the analog electrical signal. A method is also provided for monitoring the signal quality of a transmitted, modulated optical signal.
    Type: Grant
    Filed: April 2, 2004
    Date of Patent: June 10, 2014
    Assignee: Finisar Corporation
    Inventors: Jorg-Reinhardt Kropp, Jens Fiedler
  • Patent number: 8750726
    Abstract: Techniques are provided for estimation of the chromatic dispersion (CD) in an optical signal received by an optical receiver. The techniques involve iteratively adjusting dispersion compensation coefficients of one or more filters configured to compensate for the CD in the received optical signal. At each iteration of the dispersion compensation coefficient adjustment, electrical domain signals are filtered to generate digitally-filtered signals. The electrical domain signals are generated based on the received optical signal. Also at each iteration of the dispersion compensation coefficient adjustment, an amplitude histogram of the digitally-filtered signals is generated. The amplitude histograms generated at each iteration are evaluated to generate an estimate of the chromatic dispersion in the received optical signal.
    Type: Grant
    Filed: August 16, 2011
    Date of Patent: June 10, 2014
    Assignee: Cisco Technology, Inc.
    Inventor: Jonas Geyer
  • Publication number: 20140153920
    Abstract: Methods, systems, and devices are described for a digital demodulator device for processing received optical signals. The device may include a quadrature error filter that receives a digitized version of an optical signal, and removes quadrature errors to generate a filtered series of data samples. The device may also include a frequency offset removal module for performing frequency rotation on the filtered series of data samples. The device may include a chromatic dispersion compensation module which removes chromatic dispersion from horizontal and vertical polarization channels. The device may include a polarization mode dispersion (PMD)/polarization dependent loss (PDL) compensation module which compensates for interference caused by PMD and PDL. The device may also include a phase recovery module configured to track and correct phase.
    Type: Application
    Filed: February 10, 2014
    Publication date: June 5, 2014
    Applicant: ViaSat, Inc.
    Inventors: Fan Mo, William Thesling, Matthew Nimon, Sameep Dave
  • Patent number: 8744277
    Abstract: An apparatus calibrates an optical downconverter configured to receive an optical input signal at a signal input and an optical reference signal at a reference input, and to provide at multiple output nodes characterizing signals for characterizing the optical input signal. The downconverter includes receivers having corresponding optical inputs and respectively providing the characterizing signals at the output nodes, and multiple optical signal paths connected between one of the signal and reference inputs and one of the optical inputs. The apparatus includes a signal analyzing unit coupled to the output nodes and configured to receive and analyze the characterizing signals, a first switch for selectively enabling the optical input signal, and a second switch for selectively enabling the reference signal.
    Type: Grant
    Filed: March 19, 2009
    Date of Patent: June 3, 2014
    Assignee: Agilent Technologies, Inc.
    Inventor: Bernd Nebendahl
  • Patent number: 8744278
    Abstract: In a digital signal processing circuit of an optical receiver applicable to this method for electric power supply control, tap coefficients of a filter used in a waveform equalization section are calculated in a tap coefficient calculating section, based on a state of an optical fiber transmission line. Then, among the calculated tap coefficients, a tap coefficient for which an absolute value is less than a previously determined threshold is determined, and electric power supply to a circuit part of a filter corresponding to the tap coefficient is stopped. As a result, for an optical receiver that performs digital signal processing, it is possible to reduce the power consumption, while realizing waveform equalization at a high accuracy.
    Type: Grant
    Filed: June 30, 2009
    Date of Patent: June 3, 2014
    Assignee: Fujitsu Limited
    Inventors: Shoichiro Oda, Takeshi Hoshida, Hisao Nakashima, Takahito Tanimura
  • Patent number: 8744279
    Abstract: Polarization mode dispersion (PMD) in a dual-pole optical communications network is compensated for using an adaptive PMD equalizer. The PMD equalizer may include a number of substantially identical filter modules that provide partial outputs which may be combined to form a PMD compensated output. A constant modulus algorithm (CMA)-based equalizer may track PMD across both poles and generates an error signal. The CMA-based equalizer includes a filter bank, and uses an update algorithm and tap/output adjustments based on a difference between combined tap energies and an index, and feedback from a forward error correction code frame synchronizer.
    Type: Grant
    Filed: August 8, 2011
    Date of Patent: June 3, 2014
    Assignee: ViaSat, Inc.
    Inventors: Fan Mo, Sameep Dave, Lawrence W. Esker
  • Publication number: 20140147110
    Abstract: A high-speed optical receiver implemented using a low-speed light receiving element is provided, which is configured to receive an optical signal having a higher transmission rate than that received using a general avalanche photo diode (APD) by expanding a frequency bandwidth using a receiver circuit configured together with an APD in the optical receiver including the APD, an APD bias control circuit, a transimpedance amplifier (TIA) for amplifying a signal received from the APD to have low noise, and a post amplifier; and a method of implementing such a high-speed optical receiver.
    Type: Application
    Filed: November 27, 2012
    Publication date: May 29, 2014
    Applicant: OE SOLUTIONS AMERICA INC.
    Inventors: Wan Seok SEO, Bong Sin KWARK, Moon Soo PARK
  • Publication number: 20140147130
    Abstract: An optical receiver, transmitter, transceiver or transponder for bursty, framed or continuous data. The optical receiver includes a burst mode clock recovery module that recovers the clock rapidly and with a small number of preamble or overhead bits at the front end of the data. A local clock is used for timing when the recovered clock is not available. Transitions between the recovered clock and local clock are smoothed out to avoid undesirable artifacts.
    Type: Application
    Filed: February 3, 2014
    Publication date: May 29, 2014
    Inventors: Henrik N. Poulsen, Daniel Jacob Blumenthal
  • Patent number: 8737843
    Abstract: An optical homodyne communication system and method in which a side carrier is transmitted along with data bands in an optical data signal, and upon reception, the side carrier is boosted, shifted to the center of the data bands, and its polarization state is matched to the polarization state of the respective data bands to compensate for polarization mode dispersion during transmission. By shifting a boosted side carrier to the center of the data bands, and by simultaneously compensating for the effects of polarization mode dispersion, the provided system and method simulate the advantages of homodyne reception using a local oscillator. The deleterious effects of chromatic dispersion on the data signals within the data bands are also compensated for by applying a corrective function to the data signals which precisely counteracts the effects of chromatic dispersion.
    Type: Grant
    Filed: January 5, 2012
    Date of Patent: May 27, 2014
    Assignee: Teradvance Communications, LLC
    Inventors: Marcel F.C. Schemmann, Zoran Maricevic, Antonije R. Djordjevic, Darby Racey
  • Patent number: 8737848
    Abstract: An optical receiver includes: an optical amplifier amplifying an optical signal fed thereinto according to an operating current fed thereinto, the optical signal being a wavelength-multiplexed optical signal, a demultiplexer demultiplexing an optical signal output from the optical amplifier; and an operating-current control circuit selecting a monitoring target from a plurality of wavelength signals output from the demultiplexer and controlling the operating current of the optical amplifier so that optical power of the monitoring target is controlled to be a predetermined value.
    Type: Grant
    Filed: January 21, 2011
    Date of Patent: May 27, 2014
    Assignees: Fujitsu Limited, Fujitsu Optical Components Limited
    Inventors: Tadashi Ikeuchi, Naoki Kuwata
  • Patent number: 8731413
    Abstract: Methods, systems, and devices are described for modulating and demodulating data on optical signals. During modulation, at least one stream of symbol mapped bits is filtered with at least one pulse shaping filter to reduce a bandwidth of the stream of bits and to pre-compensate for at least one identified non-ideal transmission condition. The filtered bits are modulated onto a waveform in the digital domain, and the modulated filtered bits are transmitted to digital-to-analog converter. The output of the digital-to-analog converter is converted to an optical signal. During demodulation, a received optical signal is sampled at a first sampling rate at an ADC, downsampled to a lower sampling rate for filtering, filtered with at least one discrete pulse-shaping filter, upsampled for equalization and demodulation, and then equalized and demodulated.
    Type: Grant
    Filed: January 23, 2012
    Date of Patent: May 20, 2014
    Assignee: ViaSat, Inc.
    Inventors: Sameep Dave, Matthew Nimon, Fan Mo, William Thesling
  • Patent number: 8731410
    Abstract: Methods and systems for split voltage domain receiver circuits are disclosed and may include amplifying complementary received signals in a plurality of partial voltage domains. The signals may be combined into a single differential signal in a single voltage domain. Each of the partial voltage domains may be offset by a DC voltage from the other partial voltage domains. The sum of the partial domains may be equal to a supply voltage of the integrated circuit. The complementary signals may be received from a photodiode. The amplified received signals may be amplified via stacked common source amplifiers, common emitter amplifiers, or stacked inverters. The amplified received signals may be DC coupled prior to combining. The complementary received signals may be amplified and combined via cascode amplifiers. The voltage domains may be stacked, and may be controlled via feedback loops. The photodetector may be integrated in the integrated circuit.
    Type: Grant
    Filed: September 11, 2008
    Date of Patent: May 20, 2014
    Assignee: Luxtera, Inc.
    Inventor: Brian Welch
  • Patent number: 8731411
    Abstract: A polarization fluctuation compensation device, when WDM light received by, for example, an optical reception device includes a polarization scrambled optical signal and a non-polarization scrambled optical signal, collects information related to whether optical signals having respective wavelengths are polarization scrambled, obtains a target value of control parameters which are different from each other, according to the speed of polarization fluctuations in the non-polarization scrambled optical signal based on the collected information, and performs reception processing of the non-polarization scrambled optical signal by using a control parameter set as the target value. As a result, an influence of fast polarization fluctuations generated resulting from an interaction between optical signals having respective wavelengths can be reliably compensated for, thereby enabling to realize excellent reception characteristics.
    Type: Grant
    Filed: March 31, 2011
    Date of Patent: May 20, 2014
    Assignee: Fujitsu Limited
    Inventors: Shoichiro Oda, Takeshi Hoshida, Toshiki Tanaka, Hiroyuki Irie, Hiroshi Nakamoto
  • Patent number: 8731414
    Abstract: The present invention relates to an optical receiver (1) for receiving alternating-light data signals and for storing electrical energy obtained from extraneous light, having a photodiode (2) for receiving light, which comprises extraneous light and an alternating-light data signal component with a higher frequency in comparison to the extraneous light, and for converting the light into a photocurrent (IP) which comprises a data signal current (IN) and an extraneous light current (IF) said receiver additionally comprises a coupling unit (3) for coupling in and separating the data signal current generated by the optical alternating-light data signal component from the extraneous light current generated by the extraneous light, an amplifying unit (4) for amplifying the data signal current and an energy storage unit (5) which is charged by the extraneous light current (IF) and which includes a circuit for increasing voltage, wherein the energy charged in the energy storage unit (5) is used for at least partially
    Type: Grant
    Filed: February 1, 2012
    Date of Patent: May 20, 2014
    Assignee: Mechaless Systems GmbH
    Inventors: Rolf Melcher, Uwe Hill
  • Patent number: 8731412
    Abstract: An amplifier implementing with a common base circuit is disclosed. The amplifier includes the common base circuit, a current shunt, and a current supplement. The common base circuit receives an input current. The current shunt shunts the input current based on the average of the output of the pre-amplifier. The current supplement supplements a current shunted by the current shunt.
    Type: Grant
    Filed: November 15, 2011
    Date of Patent: May 20, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Makoto Ito, Taizo Tatsumi