Including Postcompensation Patents (Class 398/208)
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Patent number: 8861981Abstract: 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: GrantFiled: March 18, 2013Date of Patent: October 14, 2014Assignee: Huawei Technologies Co., Ltd.Inventors: Ling Liu, Liangchuan Li
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Patent number: 8855503Abstract: 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: GrantFiled: July 9, 2010Date of Patent: October 7, 2014Assignee: Hitachi, Ltd.Inventor: Nobuhiko Kikuchi
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Patent number: 8855504Abstract: 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: GrantFiled: June 23, 2004Date of Patent: October 7, 2014Assignee: Alcatel LucentInventor: Henning Bülow
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Patent number: 8849131Abstract: 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: GrantFiled: April 27, 2012Date of Patent: September 30, 2014Assignee: Fujitsu LimitedInventors: Lei Li, Zhenning Tao, Shoichiro Oda
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Publication number: 20140286650Abstract: 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: ApplicationFiled: February 21, 2014Publication date: September 25, 2014Applicant: FUJITSU LIMITEDInventor: Hiroshi Ogiwara
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Publication number: 20140286651Abstract: 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: ApplicationFiled: March 20, 2014Publication date: September 25, 2014Applicant: Sumitomo Electric Industries, Ltd.Inventor: Masaru TAKECHI
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Patent number: 8842992Abstract: 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: GrantFiled: March 7, 2012Date of Patent: September 23, 2014Assignee: Harris CorporationInventors: Charles Middleton, Richard DeSalvo, Peter S. Scheuter
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Publication number: 20140270809Abstract: 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: ApplicationFiled: March 18, 2013Publication date: September 18, 2014Inventor: Makoto SHIBUTANI
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Publication number: 20140270810Abstract: 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: ApplicationFiled: January 30, 2014Publication date: September 18, 2014Applicant: FUJITSU LIMITEDInventor: Hisao Nakashima
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Patent number: 8837956Abstract: 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: GrantFiled: June 28, 2012Date of Patent: September 16, 2014Assignee: Rockwell Collins, Inc.Inventors: Raymond Zanoni, Mark A. Willi, Roger A. Dana
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Patent number: 8837957Abstract: 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: GrantFiled: January 12, 2012Date of Patent: September 16, 2014Assignee: Futurewei Technologies, Inc.Inventors: Zhuhong Zhang, Yanming Li, Chuandong Li, Fei Zhu
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Publication number: 20140255042Abstract: 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: ApplicationFiled: March 7, 2014Publication date: September 11, 2014Applicant: TYCO ELECTRONICS SVENSKA HOLDINGS ABInventors: Andrei Kaikkonen, Lennart Per Olof Lundqvist, Lars-Goete Svensson, Peter Lindberg
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Patent number: 8824898Abstract: 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: GrantFiled: April 8, 2011Date of Patent: September 2, 2014Assignee: SILICON LINE GmbHInventors: Martin Groepl, Holger Hoeltke
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Patent number: 8818209Abstract: 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: GrantFiled: June 19, 2012Date of Patent: August 26, 2014Assignee: Ciena CorporationInventors: William Martin Snelgrove, Kim B. Roberts, Bertram Leesti, Shahab Oveis Gharan, Mahmoud Taherzadehboroujeni
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Publication number: 20140233966Abstract: 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: ApplicationFiled: December 22, 2013Publication date: August 21, 2014Applicant: ZTE (USA) INC.Inventors: Jianjun Yu, Bo Huang
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Patent number: 8811829Abstract: 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: GrantFiled: March 15, 2012Date of Patent: August 19, 2014Assignee: Kabushiki Kaisha ToshibaInventors: Zhiliang Yuan, Andrew James Shields
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Patent number: 8805208Abstract: 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: GrantFiled: February 3, 2012Date of Patent: August 12, 2014Assignee: Tyco Electronics Subsea Communications LLCInventors: Hongbin Zhang, Oleg Sinkin
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Patent number: 8805198Abstract: 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: GrantFiled: April 13, 2009Date of Patent: August 12, 2014Assignee: Mitsubishi Electric CorporationInventor: Takashi Mizuochi
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Patent number: 8805209Abstract: 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: GrantFiled: February 24, 2012Date of Patent: August 12, 2014Inventors: Guifang Li, Likai Zhu
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Publication number: 20140219666Abstract: 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 sType: ApplicationFiled: March 1, 2012Publication date: August 7, 2014Applicant: Technion Research and Development Foundation LTD.Inventors: Igor Tselniker, Netta Sigron, Moshe Nazarathy
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Patent number: 8798483Abstract: 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: GrantFiled: December 20, 2005Date of Patent: August 5, 2014Assignee: ZTE CorporationInventor: Huade Shu
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Patent number: 8792789Abstract: 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: GrantFiled: March 7, 2012Date of Patent: July 29, 2014Assignee: Applied Micro Circuits CorporationInventors: Badri Varadarajan, Daruish Dabiri, Subhash Roy
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Patent number: 8792785Abstract: 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: GrantFiled: May 23, 2012Date of Patent: July 29, 2014Assignee: Source Photonics, Inc.Inventors: Xu Jiang, Xin Shuai, Bing Ju, Yi Yang
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Patent number: 8787776Abstract: 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: GrantFiled: June 3, 2011Date of Patent: July 22, 2014Assignee: The Governing Council of the University of TorontoInventors: Anthony Chan Carusone, Tony Shuo-Chun Kao, Hemesh Yasotharan
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Patent number: 8787769Abstract: 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: GrantFiled: July 14, 2010Date of Patent: July 22, 2014Assignee: Nippon Telegraph and Telephone CorporationInventors: Koichi Ishihara, Takayuki Kobayashi, Riichi Kudo, Yasushi Takatori, Munehiro Matsui, Masato Mizoguchi, Tadao Nakagawa, Etsushi Yamazaki, Akihide Sano, Yutaka Miyamoto, Eiji Yoshida, Shogo Yamanaka
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Patent number: 8774262Abstract: 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: GrantFiled: March 25, 2011Date of Patent: July 8, 2014Assignee: Vitesse Semiconductor CorporationInventors: Sudeep Bhoja, John S. Wang, Hai Tao
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Patent number: 8768173Abstract: 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: GrantFiled: December 13, 2011Date of Patent: July 1, 2014Assignee: Fujitsu LimitedInventors: Takahito Tanimura, Takeshi Hoshida
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Patent number: 8768181Abstract: 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: GrantFiled: October 6, 2010Date of Patent: July 1, 2014Assignee: Mitsubishi Electric CorporationInventors: Kiyoshi Onohara, Hideo Yoshida, Takashi Sugihara
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Patent number: 8761614Abstract: 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: GrantFiled: June 14, 2011Date of Patent: June 24, 2014Assignee: Ciena CorporationInventors: Yuriy Greshishchev, Ian Betty, Kim B. Roberts
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Patent number: 8761609Abstract: A receiver for fiber optic communications.Type: GrantFiled: November 2, 2010Date of Patent: June 24, 2014Assignee: 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
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Publication number: 20140169797Abstract: 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: ApplicationFiled: December 18, 2013Publication date: June 19, 2014Inventors: Aaron Callard, Mohammadhadi Baligh, Kelvin Kar Kin Au
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Patent number: 8755696Abstract: 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: GrantFiled: May 30, 2012Date of Patent: June 17, 2014Assignee: Electronics and Telecommunications Research InstituteInventor: Jyung-Chan Lee
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Patent number: 8755695Abstract: 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: GrantFiled: September 25, 2013Date of Patent: June 17, 2014Assignee: Huawei Technologies Co., Ltd.Inventors: Jing Li, Dongning Feng, Dongyu Geng, Frank Effenberger
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Publication number: 20140161470Abstract: 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: ApplicationFiled: February 12, 2014Publication date: June 12, 2014Applicant: ViaSat, Inc.Inventors: Yuri Zelensky, Fan Mo
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Publication number: 20140161442Abstract: 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: ApplicationFiled: August 8, 2012Publication date: June 12, 2014Applicant: AEROSPACE SCIENCE & INDUSTRY SHENZHEN (GROUP) CO., LTD.Inventors: Jun Yang, Lin Cheng
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Patent number: 8750725Abstract: 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: GrantFiled: April 2, 2004Date of Patent: June 10, 2014Assignee: Finisar CorporationInventors: Jorg-Reinhardt Kropp, Jens Fiedler
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Patent number: 8750726Abstract: 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: GrantFiled: August 16, 2011Date of Patent: June 10, 2014Assignee: Cisco Technology, Inc.Inventor: Jonas Geyer
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Publication number: 20140153920Abstract: 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: ApplicationFiled: February 10, 2014Publication date: June 5, 2014Applicant: ViaSat, Inc.Inventors: Fan Mo, William Thesling, Matthew Nimon, Sameep Dave
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Patent number: 8744277Abstract: 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: GrantFiled: March 19, 2009Date of Patent: June 3, 2014Assignee: Agilent Technologies, Inc.Inventor: Bernd Nebendahl
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Patent number: 8744278Abstract: 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: GrantFiled: June 30, 2009Date of Patent: June 3, 2014Assignee: Fujitsu LimitedInventors: Shoichiro Oda, Takeshi Hoshida, Hisao Nakashima, Takahito Tanimura
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Patent number: 8744279Abstract: 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: GrantFiled: August 8, 2011Date of Patent: June 3, 2014Assignee: ViaSat, Inc.Inventors: Fan Mo, Sameep Dave, Lawrence W. Esker
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Publication number: 20140147110Abstract: 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: ApplicationFiled: November 27, 2012Publication date: May 29, 2014Applicant: OE SOLUTIONS AMERICA INC.Inventors: Wan Seok SEO, Bong Sin KWARK, Moon Soo PARK
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Publication number: 20140147130Abstract: 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: ApplicationFiled: February 3, 2014Publication date: May 29, 2014Inventors: Henrik N. Poulsen, Daniel Jacob Blumenthal
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Patent number: 8737843Abstract: 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: GrantFiled: January 5, 2012Date of Patent: May 27, 2014Assignee: Teradvance Communications, LLCInventors: Marcel F.C. Schemmann, Zoran Maricevic, Antonije R. Djordjevic, Darby Racey
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Patent number: 8737848Abstract: 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: GrantFiled: January 21, 2011Date of Patent: May 27, 2014Assignees: Fujitsu Limited, Fujitsu Optical Components LimitedInventors: Tadashi Ikeuchi, Naoki Kuwata
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Patent number: 8731413Abstract: 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: GrantFiled: January 23, 2012Date of Patent: May 20, 2014Assignee: ViaSat, Inc.Inventors: Sameep Dave, Matthew Nimon, Fan Mo, William Thesling
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Patent number: 8731410Abstract: 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: GrantFiled: September 11, 2008Date of Patent: May 20, 2014Assignee: Luxtera, Inc.Inventor: Brian Welch
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Patent number: 8731411Abstract: 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: GrantFiled: March 31, 2011Date of Patent: May 20, 2014Assignee: Fujitsu LimitedInventors: Shoichiro Oda, Takeshi Hoshida, Toshiki Tanaka, Hiroyuki Irie, Hiroshi Nakamoto
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Patent number: 8731414Abstract: 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 partiallyType: GrantFiled: February 1, 2012Date of Patent: May 20, 2014Assignee: Mechaless Systems GmbHInventors: Rolf Melcher, Uwe Hill
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Patent number: 8731412Abstract: 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: GrantFiled: November 15, 2011Date of Patent: May 20, 2014Assignee: Sumitomo Electric Industries, Ltd.Inventors: Makoto Ito, Taizo Tatsumi