Reducing Distortion Or Dispersion Patents (Class 398/159)
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Patent number: 8737839Abstract: A network design apparatus includes an input unit configured to receive network information that indicates nodes connected by optical transmission paths and path information that indicates paths between the nodes; an design unit configured to perform, based on the network information and the path information, wavelength dispersion compensation design using a constraint condition that a path whose span count is larger than a span count of another path that does not satisfy a transmission condition does not satisfy the transmission condition; and an output unit configured to output a result obtained by the design unit.Type: GrantFiled: August 17, 2010Date of Patent: May 27, 2014Assignee: Fujitsu LimitedInventors: Yutaka Takita, Toru Katagiri, Tomohiro Hashiguchi, Kazuyuki Tajima
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Patent number: 8731404Abstract: An optical transmission system is provided. The optical transmission system includes a user side optical repeater device (ORD), a central office side ORD, and wavelength multiplexing and wavelength de-multiplexing functions (MUX/DEMUX). The user side optical repeater device (ORD) is to be connected with a user side optical network unit (ONU), transmits data in two ways, and is used for wavelength division multiplexing (WDM). The central office side ORD is to be connected with a central office side optical line terminal (OLT), transmits data in two ways, and is used for WDM. The wavelength multiplexing and a wavelength de-multiplexing functions (MUX/DEMUX), are used for relaying between the user side ORD and the central office side ORD.Type: GrantFiled: November 30, 2012Date of Patent: May 20, 2014Assignee: Furukawa Electric Co., Ltd.Inventor: Masayuki Miura
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Patent number: 8718474Abstract: Methods and devices for compensating for chromatic dispersion are shown that include receiving an input data signal, applying a filter to the data signal, and outputting a CD compensated signal. Applying the filter includes convolving known filter coefficients with a plurality of delayed versions of the data signal using addition and at least one inverse sign operation or using lookup tables and combining outputs to produce a CD compensated signal.Type: GrantFiled: October 6, 2011Date of Patent: May 6, 2014Assignee: NEC Laboratories America, Inc.Inventors: Dayou Qian, Junqiang Hu, Ting Wang, Yoshiaki Aono, Tsutomu Tajima
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Patent number: 8712237Abstract: Signals propagating in wavelength division multiplexing (WDM) optical networks suffer from loss, which decreases optical signal-to-noise ratios (OSNRs) and degrades a quality of received transmissions. Present methods of boosting OSNRs involve regeneration using transponders, which scale in complexity with the number of WDM channels. Optical amplifiers may boost signal strength, but amplified spontaneous emission (ASE) noise often reduces OSNR despite increases in signal strength, although changing the amplifier operating settings may reduce emitted ASE noise power. A method or corresponding apparatus in an example embodiment of the present invention provides a planning tool for deploying optical amplifiers in an optical network in a manner that reduces the need for optical regeneration, reducing cost and complexity of the deployed network.Type: GrantFiled: August 15, 2008Date of Patent: April 29, 2014Assignee: Tellabs Operations, Inc.Inventors: David W. Jenkins, Ramasubramanian Anand, Hector Ayala, Julia Y. Larikova, Kenneth M. Fisher
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Patent number: 8712252Abstract: To efficiently apply jitter to an optical signal using a simple configuration, provided is an optical signal output apparatus that outputs an optical pulse pattern signal including jitter, the optical signal generating apparatus comprising a light source section that outputs an optical signal having an optical frequency corresponding to a frequency control signal; an optical modulation section that modulates the optical signal output by the light source section, according to a designated pulse pattern; and an optical jitter generating section that delays an optical signal passed by the optical modulation section according to the optical frequency, to apply jitter to the optical signal.Type: GrantFiled: October 18, 2011Date of Patent: April 29, 2014Assignee: Advantest CorporationInventors: Shin Masuda, Kazunori Shiota
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Patent number: 8705977Abstract: Methods, systems, and devices are described for tap adjustment and reseeding in a digital filter. Filter and signal characteristics are measured and tap adjustments and reseeding of tap values may be performed based on the filter and signal characteristics. Filter characteristics that may be measured include a filter center of mass which may provide an indication that filter taps for a filter may be drifting toward a filter edge and thus reducing the dynamic range of the filter. Signal characteristics may include a timing offset between received input signals, and characteristics related to which of a particular input signal is present at a filter output. Filter taps, according to various embodiments, may be adjusted, and/or re-initialized responsive to one or more of the signal or filter characteristics.Type: GrantFiled: January 23, 2012Date of Patent: April 22, 2014Assignee: ViaSat, Inc.Inventors: Fan Mo, Sameep Dave, Yuri Zelensky
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Patent number: 8693898Abstract: An adaptive equalizer includes a finite impulse response filter with a predetermined number of taps; and a tap coefficient adaptive controller having a register to hold tap coefficients for the filter, a weighted center calculator to calculate a weighted center of the tap coefficients, and a tap coefficient shifter to shift the tap coefficients based on a calculation result of the weighted center. During an initial training period, the tap coefficient shifter shifts the tap coefficients on a symbol data basis such that a difference between the calculated weighted center of the tap coefficients and a tap center defined by the number of taps is minimized.Type: GrantFiled: October 14, 2011Date of Patent: April 8, 2014Assignee: Fujitsu LimitedInventors: Nobukazu Koizumi, Kazuhiko Hatae, Noriyasu Nakayama, Koji Nakamuta, Hisao Nakashima, Kosuke Komaki
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Patent number: 8693886Abstract: In an optical multilevel transmitter (210), a polar representation of an optical multilevel signal (r, ?) is generated by a polar coordinate multilevel signal generation circuit (212), input to an optical amplitude modulator (211) and a polar coordinate type optical phase modulator (201), and output as an optical multilevel modulated signal (213). The polar coordinate type optical phase modulator (201) generates an optical phase rotation proportional to an input voltage, so the modulation distortion of the electric signal is transferred in a linear form to the optical phases of the optical multilevel modulated signal (213). In an optical multilevel receiver (219), a received signal is input to two sets of optical delay detectors (133) and balance receivers (134) and directly demodulated, and a differential phase ?? for the received signal is calculated by arctangent computation from the output signal.Type: GrantFiled: January 7, 2010Date of Patent: April 8, 2014Assignee: Hitachi, Ltd.Inventor: Nobuhiko Kikuchi
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Patent number: 8693897Abstract: 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: GrantFiled: August 8, 2011Date of Patent: April 8, 2014Assignee: ViaSat, Inc.Inventors: Fan Mo, William Thesling, Matthew Nimon, Sameep Dave
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Patent number: 8693885Abstract: Certain aspects of a method and system for optimum channel equalization between a host Serializer-Deserializer (SerDes) and an optical module may compensate and reduce dispersion loss along an electrical transmit path of a transmitter and an optical transmit path coupled to the transmitter via pre-emphasis. The data degradation as a result of the dispersion loss along the electrical transmit path of the transmitter and the optical transmit path coupled to the transmitter may be recovered by equalizing signals received via an electrical receive path of a receiver communicatively coupled to the transmitter.Type: GrantFiled: March 4, 2010Date of Patent: April 8, 2014Assignee: Broadcom CorporationInventor: Ali Ghiasi
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Patent number: 8687974Abstract: 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: GrantFiled: August 8, 2011Date of Patent: April 1, 2014Assignee: ViaSat, Inc.Inventors: Yuri Zelensky, Fan Mo
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Patent number: 8687973Abstract: A voltage generator (400) includes a resistor ladder including resistors (4000-4008) which divide a supplied voltage to generate a plurality of reference voltages, a resistor (4009) provided between a power supply voltage (VCC) and one terminal of the resistor ladder, and a resistor (4010) provided between a power supply voltage (VEE) and the other terminal of the resistor ladder.Type: GrantFiled: August 12, 2009Date of Patent: April 1, 2014Assignee: Nippon Telegraph and Telephone CorporationInventors: Hideyuki Nosaka, Munehiko Nagatani, Shogo Yamanaka, Kimikazu Sano, Koichi Murata, Kiyomitsu Onodera, Takatomo Enoki
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Publication number: 20140086578Abstract: Multimode optical fiber systems with adjustable chromatic modal dispersion compensation are disclosed, wherein the system includes a VCSEL light source and primary and secondary optically coupled multimode optical fibers. Because the VCSEL light source has a wavelength spectrum that radially varies, its use with the primary multimode optical fiber creates chromatic modal dispersion that reduces bandwidth. The compensating multimode optical fiber is designed to have a difference in alpha parameter relative to the primary multimode optical fiber of ?0.1?????0.9. This serves to create a modal delay opposite to the chromatic modal dispersion. The compensation is achieved by using a select length of the compensating multimode optical fiber optically coupled to an output end of the primary multimode optical fiber. The compensating multimode optical fiber can be configured to be bend insensitive.Type: ApplicationFiled: March 15, 2013Publication date: March 27, 2014Applicant: Coming IncorporatedInventor: Corning Incorporated
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Patent number: 8682174Abstract: An optical receiver according to the invention includes a polarization diversity unit receiving a polarization multiplexed optical signal obtained by multiplexing two optical signals having a same frequency band of carrier waves and polarization states orthogonal to each other, and a frequency domain equalization unit receiving signal components parallel to mutually orthogonal polarization axes from the polarization diversity unit, wherein the frequency domain equalization unit includes filters for which filter coefficients thereof are set for compensating degradation of transmission characteristics in one optical signal without polarization multiplexing by means of the frequency domain equalization.Type: GrantFiled: February 14, 2011Date of Patent: March 25, 2014Assignee: NEC CorporationInventor: Daisaku Ogasahara
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Patent number: 8670675Abstract: A distortion compensation circuit including a configurable delay may be used with one or more non-linear elements, such as a laser, to compensate for distortion generated by the non-linear element(s), for example, in broadband RF applications. Embodiments of the distortion compensation circuit may include a primary signal path with a configurable delay segment and a secondary signal path including at least one distortion generator. The configurable delay segment may be selectively configured to provide different delay settings to accommodate different RF loading conditions such that the delayed RF signal on the primary signal path is aligned with the distortion products generated on the secondary signal path when combined to form an RF signal with distortion compensation.Type: GrantFiled: December 22, 2010Date of Patent: March 11, 2014Assignee: Applied Optoelectronics, Inc.Inventors: Jun Zheng, Yi Wang
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Patent number: 8660434Abstract: A printed circuit board includes a substrate, a signal output circuit formed on the substrate for outputting a clock signal, a shield for covering the signal output circuit, a power supply wiring for connecting the signal output circuit and a power source, and a trap filter provided to the power supply wiring and provided inside the shield, for attenuating a frequency component corresponding to a frequency of clock signal. The trap filter includes a resonance circuit having one portion of the power supply wiring, an inner-layer wiring of the substrate located below the one portion of the power supply wiring, an inner-layer ground wiring of the substrate located below the inner-layer wiring, and a via hole for connecting the one portion of the power supply wiring and the inner-layer wiring.Type: GrantFiled: February 20, 2013Date of Patent: February 25, 2014Assignee: Oclaro Japan, Inc.Inventors: Osamu Kagaya, Koyu Takahashi, Taichi Kogure
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Patent number: 8660437Abstract: A fiber optic network reduces distortion present in modulated optical signals received at an optical receiver from an optical transmitter via a fiber optic link. The optical receiver analyzes a received modulated optical signal, where the wavelength of the received signal is periodically varied at the transmitter around a center wavelength over a wavelength range. Based on the analysis, the receiver generates a link transmission curve indicative of the optical power of the received signal over the wavelength range. The network disclosed herein subsequently uses the link transmission curve to reduce the distortion caused by misalignment between the operating wavelength of a transmitter laser and a peak power wavelength at the peak power of the link transmission curve. For example, the transmitter may adjust the laser operating wavelength based on a control signal received from the receiver and generated at the receiver based on the link transmission curve.Type: GrantFiled: February 25, 2011Date of Patent: February 25, 2014Assignee: Emcore CorporationInventor: Henry A. Blauvelt
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Patent number: 8655186Abstract: A reconfigurable wavelength selective dispersion compensation device RWSDCD for selective compensation of dispersion in optical channels having different wavelengths. The RWSDCD comprises a controllable wavelength selective unit WSU having a plurality of local, wavelength related input/output (I/O) ports. The RWDSD also comprises a dispersion compensation cascade comprising at least one chain of successively connected dispersion compensation units DCUs, wherein one or more of the DCUs in the chain are respectively connectable to one or more of the local I/O ports. The RWSDCD outputs one or more of the incoming optical channels upon selectively compensating chromatic dispersion in them, by controllably passing these channels via one or more DCUs of the dispersion compensation cascade.Type: GrantFiled: September 15, 2009Date of Patent: February 18, 2014Assignee: ECI Telecom Ltd.Inventors: Uri Mahlab, Avi Levy
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Patent number: 8655184Abstract: The present invention relates to a higher-order dispersion compensation device (210), the device being adapted to cooperate with a pair of optical components (P1, P2), e.g. a pair of prisms, being arranged to compensate first-order dispersion by separating different wavelengths spatially. The compensation device (210) has the form of a phase plate, wherein the phase change for each wavelength is adjusted by designing the height (h) at the corresponding position (x) of the plate so as to substantially compensate for higher-order dispersion. The invention is advantageous for obtaining a higher-order dispersion compensation device which is relatively simple to construct and use making it a quite cost-effective device. The invention also relates to a corresponding optical system and method for compensating dispersion where this is important, e.g. in a multiple-photon imaging system.Type: GrantFiled: May 20, 2009Date of Patent: February 18, 2014Assignee: Koninklijke Philips N.V.Inventors: Gert Het Hooft, Bernardus Hendrikus Wilhelmus Hendriks, Mischa Megens
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Patent number: 8655193Abstract: Provided is an optical multilevel transmission system, comprising at least one optical multilevel transmitter for transmitting an optical multilevel signal obtained and an optical multilevel receiver for receiving the optical multilevel signal. The received optical multilevel signal has a larger noise in an angular direction than in a radial direction. The optical multilevel receiver sets, in a symbol decision of the received optical multilevel signal demodulated on the complex plane, for positions of all or some of ideal signal points, a width in the angular direction of a decision area, to which each of the ideal signal points belongs and which is measured along a circumference of a circle centered at an origin and passing through a center of the each of the ideal signal points, larger than a width in the angular direction of a decision area defined based on a Euclidean distance.Type: GrantFiled: March 2, 2009Date of Patent: February 18, 2014Assignee: Hitachi, Ltd.Inventor: Nobuhiko Kikuchi
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Patent number: 8649685Abstract: A light receiving device includes: a converter digitalizing an analog signal with a given sampling clock frequency, the analog signal being obtained through a photoelectric conversion of a received optical signal; a plurality of fixed distortion compensators compensating an output signal of the converter for waveform distortion with a fixed compensation amount that is different from each other; a plurality of phase shift detector circuits detecting a sampling phase shift from an output signal of the plurality of the fixed distortion compensators; a phase-adjusting-amount determiner determining a sampling phase adjusting amount with use of an output signal of the plurality of the phase shift detector circuits; and a phase adjusting circuit reducing a phase difference between the sampling clock frequency and the received optical signal based on a determination result of the phase-adjusting-amount determiner.Type: GrantFiled: December 23, 2010Date of Patent: February 11, 2014Assignee: Fujitsu LimitedInventors: Hisao Nakashima, Takeshi Hoshida
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Patent number: 8639123Abstract: One method configures an all-optical network such that at least eighty percent of optical fiber spans of a portion of a first all-optical path of the network have substantially a first residual dispersion per span and at least eighty percent of optical fiber spans of a remainder of the first all-optical path have residual dispersions per span substantially differing from the first residual dispersion per span. The remainder of the first all-optical path includes an overlap between the first all-optical path and a second all-optical path of the network. The second all-optical path has a plurality of optical fiber spans and a substantially singly periodic dispersion map.Type: GrantFiled: May 16, 2011Date of Patent: January 28, 2014Assignee: Alcatel LucentInventors: Paul Robert Claisse, Rene′-Jean Essiambre
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Patent number: 8630545Abstract: Disclosed is an optical system including a polychromatic optical source emitting multiple transverse modes, an optical link having at least one portion of multimode optical fiber, and an optical device positioned between the optical source and the input of the multimode optical fiber. The optical device can modify the distribution of the energy coupling of the transverse modes emitted by the source in the propagation modes of the multimode optical fiber. The optical system makes it possible to use low-cost transverse multimode optical sources for producing high-bandwidth Ethernet transmission networks having excellent performance.Type: GrantFiled: November 6, 2009Date of Patent: January 14, 2014Assignee: Draka Comteq, B.V.Inventors: Asghar Gholami, Denis Molin, Pierre Sillard, Yves Lumineau
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Patent number: 8625996Abstract: An optical transmitter is provided for transmitting a wavelength multiplexed signal comprising an intensity modulation optical signal and a phase modulation optical signal through a transmission line. The optical transmitter includes a bit time difference given signal generator for generating at least two optical signals having a bit time difference therebetween, from the wavelength multiplexed signal. The optical transmitter further includes a wavelength multiplexed signal output unit to which at least two optical signals are input from the bit time difference given signal generator, and which generates and outputs a wavelength multiplexed signal in which the bit time difference was given between the phase modulation optical signal and the phase modulation optical signal.Type: GrantFiled: November 14, 2007Date of Patent: January 7, 2014Assignee: Fujitsu LimitedInventors: Toshiki Tanaka, Hisao Nakashima, Takeshi Hoshida, Toru Katagiri, Hiroki Ooi, Akira Miura
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Patent number: 8626001Abstract: There arises a problem that power consumption increases along with an increasing throughout of an FEC function effective in speeding up of a transmission speed. FEC function information necessary for a system is prepared, and multiple FEC functions are properly used according to a selected transmission line, etc.Type: GrantFiled: September 23, 2011Date of Patent: January 7, 2014Assignee: Hitachi, Ltd.Inventors: Masafumi Kamakura, Koji Takatori, Yasuyuki Fukashiro, Tetsuya Uda, Hidemasa Narita
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Publication number: 20140003822Abstract: An apparatus for optical communication and optical communication method are provided, the method comprising the steps of generating an optical signal for transmitting the sequence of information data, transmitting the sequence of information data as a sequence of transmit matrices, S(k) being the k-th transmit matrix and k being a positive integer, and wherein the sequence of transmit matrices is transmitted through an optical channel characterized by a unitary channel matrix H, receiving a sequence of receive matrices, the k-th receive matrix R(k) being expressed as: R(k)=H·S(k)+N(k) wherein k is a positive integer and N(k) is a complex matrix of noise samples and providing a sequence of decision matrices, the k-th decision matrix D(k) being expressed as: D(k)=RH(k?1)R(k).Type: ApplicationFiled: December 30, 2010Publication date: January 2, 2014Applicant: NOKIA SIEMENS NETWORKS OYInventors: Stefano Calabro, Bernhard Spinnler
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Patent number: 8620160Abstract: An optical transmission apparatus includes a reception part for receiving a wavelength division multiplexed (WDM) signal reached via optical amplifiers; a measuring part for measuring an optical power level of each wavelength of the WDM signal received by the reception part; a determination part for determining whether an amount of tilt of the WDM signal calculated based on measurement results of the measuring part is suitable or not; an operation part for calculating the tilt correction amount to be applied to tilt correction processing performed by the optical amplifiers if the amount of tilt of the WDM signal is not suitable; and a notification part for notifying the optical amplifiers of the tilt correction amount.Type: GrantFiled: July 8, 2008Date of Patent: December 31, 2013Assignee: Fujitsu LimitedInventor: Miki Onaka
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Patent number: 8615172Abstract: A method for arranging relay stations in an optical transmission system including relay stations arranged so that optical signals at a first transmission speed can be transmitted from a transmission end to a reception end, includes: judging whether a transmission of optical signals at a second transmission speed different from the first transmission speed in a section connecting arbitrary two of the relay stations where a regenerative repeater station capable of regenerating optical signals can be arranged is possible; determining a combination of sections judged to be capable of performing transmission that enables a transmission of optical signals from the transmission end to the reception end; and making both ends of respective sections of the determined combination be the relay stations where the regenerative repeater station is arranged, wherein the judging includes a judgment condition which is satisfied in a section including sections but unsatisfied in one of the sections.Type: GrantFiled: August 9, 2011Date of Patent: December 24, 2013Assignee: Fujitsu LimitedInventor: Takuya Miyashita
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Patent number: 8615171Abstract: A method for joint transmitter and receiver processing for computationally efficient equalization in polarization multiplexed (POLMUX) optical orthogonal frequency division multiplexed (OFDM) transmission with direct detection.Type: GrantFiled: March 31, 2011Date of Patent: December 24, 2013Assignee: NEC Laboratories America, Inc.Inventors: Neda Cvijetic, Narayan Prasad, Dayou Qian, Ting Wang
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Patent number: 8611762Abstract: A system and method are disclosed which compensate for chromatic dispersion and polarization mode dispersion in a digital signal. The signal is adjusted for chromatic dispersion in the frequency-domain. The signal is then converted to the time-domain and at least a portion of the signal is estimated to produce channel parameters. The channel parameters are converted to the frequency domain and used to compensate for polarization mode dispersion in the signal.Type: GrantFiled: November 10, 2010Date of Patent: December 17, 2013Assignee: NEC Laboratories America, Inc.Inventors: Junqiang Hu, Ting Wang
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Patent number: 8611748Abstract: A WDM optical transmission system includes a plurality of optical transmission devices, each of which include a first memory that stores a first control program that controls a dispersion compensation amount in a host device; a processor to execute the first control program; a notification frame transmission circuit that transmits an information indicating a setting value of the dispersion compensation amount and a detection result corresponding to the setting value to another device; a third memory that stores a second control program that calculates a control value of the dispersion compensation amount in the another device; and a control frame transmission circuit that transmits the control value to the another device, wherein the processor executes the second control program when a problem occurs in the another device, and controls the dispersion compensation amount in the host device when a problem occurs in the host device.Type: GrantFiled: March 26, 2012Date of Patent: December 17, 2013Assignee: Fujitsu LimitedInventors: Makoto Yoshimi, Yoshiyuki Maeda
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Patent number: 8611763Abstract: A method (10) of compensating phase noise in a coherent optical communications network. The method comprises: receiving a traffic sample (12); receiving an optical carrier and determining a phase noise estimate for the optical carrier (14); and removing the phase noise estimate from the traffic sample to form a phase noise compensated traffic sample (16).Type: GrantFiled: September 2, 2010Date of Patent: December 17, 2013Assignee: Telefonaktiebolaget L M Ericsson (publ)Inventors: Marco Secondini, Tommaso Foggi, Giulio Colavolpe, Gianluca Meloni, Luca Poti, Enrico Forestieri
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Patent number: 8606108Abstract: The present disclosure relates to dispersion slope compensation and dispersion map management systems and methods in an optical network utilizing a reconfigurable optical add-drop multiplexer (ROADM) with a plurality of different values of dispersion compensation modules (DCMs). The DCMs form a dispersion compensation ladder at certain intermediate nodes in the optical network to provide dispersion slope compensation and dispersion map management. The reconfigurable routing structure of the ROADM enables these intermediate nodes to route individual wavelengths to any one of the DCMs as required for the particular path of the wavelength. Advantageously, the present invention removes the requirement for banded compensation at receiver nodes and allows for dispersion map management at intermediate points along a fiber route as opposed to bulk compensation at the receiver.Type: GrantFiled: June 25, 2009Date of Patent: December 10, 2013Assignee: Ciena CorporationInventor: Balakrishnan Sridhar
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Patent number: 8606104Abstract: A wavelength selective switch includes a substrate. On the substrate, the wavelength selective switch includes at least one input port, a dispersive element, a light converging element, a light deflecting member, an output port, and a driving mechanism which drives at least one of the dispersive element, the light condenser element, and the light deflecting member, and drive by the driving mechanism is a rotational drive around an axis perpendicular to the substrate, for the dispersive element, and is a translational drive in a direction of dispersion of wavelength with respect to the substrate, for the light condenser element or the light deflecting member.Type: GrantFiled: March 4, 2011Date of Patent: December 10, 2013Assignee: Olympus CorporationInventors: Takehiro Yoshida, Koji Matsumoto, Satoshi Watanabe, Masato Narusawa, Hirofumi Eto
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Patent number: 8600243Abstract: An apparatus and method for correcting for the polarization mode distortion of an optical signal is described. The optical data signal to be transmitted is processed by a switch configured to place the signal into a plurality of polarization states on a periodic basis. At the receiving end of the system, a portion to the signal is coupled to a polarimeter and the wavelength-dependent state of polarization (SOP) of the received signal determined for the plurality of polarization states imposed on the transmitted signal. The data for two of the transmitted polarization states is selected to be used as the basis for correcting the SOP so as to compensate for the wavelength dependence thereof. The corrections may be applied in an optical pulse shaper.Type: GrantFiled: April 17, 2009Date of Patent: December 3, 2013Assignee: Purdue Research FoundationInventors: Houxun Miao, Andrew M. Weiner
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Patent number: 8599051Abstract: A time-interleaved A/D converter apparatus has a primary signal A/D converter circuit group that is time-interleaved with a combination of N A/D converter circuits, a correction signal generation part operable to receive the input analog signal and a 1/m-sampling signal having a speed that is 1/m of a rate of the sampling signal inputted to the primary signal A/D converter circuit group, to extract a dispersion of a transmission line that is immanent in the input analog signal, and to output the dispersion as a dispersion compensation control signal used for digital signal compensation, and a signal processing part operable to convert the N digital signals into one digital signal based upon the dispersion compensation control signal and to compensate a dispersion included in the converted digital signal.Type: GrantFiled: March 1, 2011Date of Patent: December 3, 2013Assignee: NEC CorporationInventors: Nobuhide Yoshida, Hidemi Noguchi
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Publication number: 20130315607Abstract: System and method for compensating distortions introduced by an optical channel and by at least one directly modulated transmitting laser that transmits a modulated optical signal that carries data to a receiving end over the optical channel.Type: ApplicationFiled: November 7, 2011Publication date: November 28, 2013Applicant: BEN-GURION UNIVERSITY OF THE NEGEV, RESEARCH AND DEVELOPMENT AUTHORITYInventors: Dan Sadot, Nir Sheffi
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Patent number: 8594510Abstract: Proposed is a light module (110) comprising at least two primary light sources (111,112,113) capable of emitting a primary color light. This allows the light module to emit light having intensity (Y) and color coordinates (x,y) through additive color mixing of the constituent primary colors. The light module further comprises an modulator (115) capable of modulating the primary light sources enabling embedment of data in the light emitted. The modulator (115) is arranged to modulate the color coordinates of the light emitted for embedding the data. This is especially advantageous as the sensitivity of the human eye to changes in color is lower than to changes in intensity. The invention thus advantageously allows embedding the data into the light emitted from the light modules (110) of an illumination system (100) without reducing the performance of its primary function as an aid to human vision.Type: GrantFiled: April 27, 2009Date of Patent: November 26, 2013Assignee: Koninklijke Philips N.V.Inventors: Tim Corneel Wilhelmus Schenk, Lorenzo Feri, Paulus Henricus Antonius Damink, Martin Maurice Vernhout, Dragan Sekulovski
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Patent number: 8594515Abstract: An optical phase conjugator that can be deployed within a long-haul fiber-optic link of an optical WDM system to improve the system's tolerance to intra- and inter-channel nonlinear effects. In one embodiment, the optical phase conjugator has a digital signal processor configured to perform, in the digital electrical domain, a phase-conjugation transformation for various components of a WDM signal so that certain signal distortions imposed on that signal in the front portion of the fiber-optic link are reduced in the back portion of the link. Advantageously, the optical phase conjugator is flexibly configurable to employ an input-to-output carrier-frequency-mapping configuration that is most beneficial under particular operating conditions. mapping configuration that is most beneficial under particular operating conditions.Type: GrantFiled: March 3, 2011Date of Patent: November 26, 2013Assignee: Alcatel LucentInventors: Xiang Liu, Chandrasekhar Sethumadhavan, Robert W. Tkach
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Patent number: 8588607Abstract: Methods, systems, and computer program products are provided for measuring modal dispersion in a bi-directional dual-multimode fiber optic network (BDON). A modal dispersion measurement system includes a computer processor that is programmed to receive a first pulse width of a first pulse. The first pulse may be communicated over the BDON that is coupled to the processor. A second pulse width of a second pulse is received, the second pulse width being indicative of the modal dispersion. The second pulse width and the first pulse width are compared by the computer processor to determine a distortion error. A measurement of the modal dispersion is validated in accordance to the distortion error.Type: GrantFiled: January 29, 2009Date of Patent: November 19, 2013Assignee: Hewlett-Packard Development Company, L.P.Inventors: Oladeji Bamidele Akanbi, Jerry G. Aguren
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Patent number: 8582979Abstract: From an real valued OFDM signal (S0(t)) is a baseband signal (SB(t)) derived and converted into a complex single sideband modulation signal (n(t)). This is modulated onto an optical carrier (fOC) to generate a SSB transmission signal (SOT) having a small bandwidth an carrying the information in the envelope or in the power of the envelope. According to the modulation direct detection is possible. Only a small bandwidth is necessary for the transmission.Type: GrantFiled: August 18, 2008Date of Patent: November 12, 2013Assignee: Nokia Siemens Networks OYInventors: Christian Alexander Bunge, Matthias Schuster, Bernhard Spinnler
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Patent number: 8582983Abstract: A method and system for generating multi-subcarriers is disclosed. Re-circulating frequency shifters—based on the frequency shifting in two cascading phase modulators—are used to generate 112 subcarriers with stable architecture since there is no direct current bias in phase modulators.Type: GrantFiled: March 2, 2012Date of Patent: November 12, 2013Assignees: ZTE Corporation, ZTE (USA) Inc.Inventor: Jianjun Yu
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Patent number: 8571414Abstract: An optical transmission device includes: a variable dispersion compensator to give chromatic dispersion and output an input light, a branching unit to branch the light output from the variable dispersion compensator to a first part and a second part, a reproduction unit to reproduce an electric signal from the first part of the input light, a monitor unit to perform reproducing processing on the electric signal from the second part of the input light, control the variable dispersion compensator based on a result of the reproducing processing, and has a sensitivity to a variation of the chromatic dispersion which is higher than the sensitivity to the variation of the chromatic dispersion of the reproduction unit.Type: GrantFiled: August 27, 2010Date of Patent: October 29, 2013Assignee: Fujitsu LimitedInventor: Toshihiro Ohtani
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Patent number: 8571412Abstract: An apparatus for simulating radio frequency (RF) signal propagation characteristics in a wireless communication network is disclosed. The apparatus includes a first RF terminal and a second RF terminal. A first optical modulator is in electrical communication with the first RF terminal. An optical delay line is in optical communication with the first optical modulator. A first optical demodulator is in optical communication with the optical delay line and in electrical communication with the first RF terminal. A second optical demodulator is in optical communication with the optical delay line and in electrical communication with the second RF terminal. A second optical modulator is in electrical communication with the second RF terminal and in optical communication with the optical delay line.Type: GrantFiled: November 6, 2012Date of Patent: October 29, 2013Assignee: Eastern Optx, Inc.Inventors: Joseph Mazzochette, Edward J. MacMullen, Jerome Lomurno
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Patent number: 8565610Abstract: Embodiments of the invention are described in which correlated virtual data streams are managed within an optical network connection. In certain embodiments of the invention, a client signal is allocated across a plurality of transport wavelength channels according to various transposition methods. The assignment of portions of the client signal to corresponding wavelengths may depend on various factors including channel utilization within the transport network and skew characteristics between particular wavelengths.Type: GrantFiled: June 18, 2008Date of Patent: October 22, 2013Assignee: Infinera CorporationInventors: Edward Sprague, Charles H. Joyner
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Publication number: 20130272719Abstract: The embodiments of the present invention provide a method and an apparatus for compensating nonlinear distortions in an intensity modulation-direct detection (IM-DD) system; wherein the method comprises: calculating, according to nonlinear coefficients and differences between values of an input signal at different time, nonlinear distortions of the input signal, so as to eliminate the nonlinearity distortions. By applying the method and the apparatus provided by the embodiments of the present invention, nonlinear cost of the IM-DD system can be effectively reduced, thereby improving the system capacity.Type: ApplicationFiled: April 11, 2013Publication date: October 17, 2013Applicant: FUJITSU LIMITEDInventors: Weizhen YAN, Bo Liu, Lei Li, Zhenning Tao, Toshiki Tanaka
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Publication number: 20130272718Abstract: A system and method for filtering and enhancing signals from a noise background based on the nonlinear interaction of waves. The system and method amplify low-level signals, hide information in the signals, and then nonlinearly recover the signals. With the present invention, this can be performed for both spatial beams and temporal pulses. The signal self-filters and self-amplifies at the expense of the surrounding noise via the nonlinear medium.Type: ApplicationFiled: March 22, 2013Publication date: October 17, 2013Inventors: Jason W. Fleischer, Dmitry V. Dylov
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Patent number: 8559820Abstract: A complex orthogonal code in the present invention is one in which each row of a square matrix of N rows and N columns in which an element of an mth row and nth column is exp[2?j(m?1)(n?1)/N] (where j is an imaginary unit) is adopted as a code word. An optical orthogonal code for Optical Code Division Multiplexing/Optical Code Division Multiple Access (OCDM/OCDMA) is realized by a train of N-number of optical pulses corresponding to the argument (phase) of the code elements. An optical transmitter or optical receiver includes an optical correlator provided with a sampled Bragg grating having a plurality of Bragg gratings disposed serially at regular intervals inside an optical waveguide. The optical correlator is allocated any one of the code words. In the optical transmitter, an optical signal to be transmitted is encoded by the optical correlator. In the receiver, a received optical signal is decoded by the optical correlator.Type: GrantFiled: December 30, 2010Date of Patent: October 15, 2013Assignee: University of YamanashiInventor: Masanori Hanawa
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Publication number: 20130259490Abstract: This disclosure describes techniques to sample electrical data streams in coherent receivers. For instance, an analog-to-digital converter (ADC) samples the received electrical data stream at a sampling rate that is nominally twice or greater than twice the symbol rate of the electrical data stream that the ADC receives. A digital filter receives the digital data stream from the ADC, and digitally filters the digital data streams to output a filtered digital electrical data stream at an effective sampling rate that is less than the sampling rate and less than twice the symbol rate, and greater than or equal to the symbol rate.Type: ApplicationFiled: March 29, 2012Publication date: October 3, 2013Applicant: JUNIPER NETWORKS, INC.Inventors: Christian Malouin, Theodore John Schmidt, Bo Zhang, Elias Simpson, Roberto Marcoccia
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Patent number: 8543005Abstract: Embodiments of the present invention relate to systems and methods for distributing an intentionally skewed optical-clock signal to nodes of a source synchronous computer system. In one system embodiment, a source synchronous system comprises a waveguide, an optical-system clock optically coupled to the waveguide, and a number of nodes optically coupled to the waveguide. The optical-system clock generates and injects a master optical-clock signal into the waveguide. The master optical-clock signal acquiring a skew as it passes between nodes. Each node extracts a portion of the master optical-clock signal and processes optical signals using the portion of the master optical-clock signal having a different skew for the respective extracting node.Type: GrantFiled: April 30, 2008Date of Patent: September 24, 2013Assignee: Hewlett-Packard Development Company, L.P.Inventors: Nathan L. Binkert, Norman P. Jouppi, Robert S. Schreiber, Jung Ho Ahn