For Modulator Control Patents (Class 398/198)
  • Patent number: 10326582
    Abstract: An optical transmitter includes: an optical modulator, a phase adjustment circuit, first and second synchronization circuits, and first and second drive circuits. The optical modulator includes a first modulation area and a second modulation area that is provided at output side of the first modulation area. The phase adjustment circuit adjusts a phase of a first clock signal so as to generate a second clock signal. The first and second synchronization circuits respectively output first and second electric signals in synchronization with the first and second clock signals. The first and second drive circuits respectively drive the first and second modulation areas with the first and second electric signals.
    Type: Grant
    Filed: March 16, 2018
    Date of Patent: June 18, 2019
    Assignee: FUJITSU LIMITED
    Inventors: Yasufumi Sakai, Takayuki Shibasaki
  • Patent number: 10116391
    Abstract: The present invention relates to telecommunication techniques and integrated circuit (IC) devices. More specifically, embodiments of the present invention provide an off-quadrature modulation system. Once an off-quadrature modulation position is determined, a ratio between DC power transfer amplitude and dither tone amplitude for a modulator is as a control loop target to stabilize off-quadrature modulation. DC power transfer amplitude is obtained by measuring and sampling the output of an optical modulator. Dither tone amplitude is obtained by measuring and sampling the modulator output and performing calculation using the optical modulator output values and corresponding dither tone values. There are other embodiments as well.
    Type: Grant
    Filed: November 2, 2017
    Date of Patent: October 30, 2018
    Assignee: INPHI CORPORATION
    Inventors: Todd Rope, Radhakrishnan L. Nagarajan, Hari Shankar
  • Patent number: 10050714
    Abstract: There is provided a transmission apparatus includes: a first modulator configured to modulate a first electrical signal to a second electrical signal that is a multicarrier signal including a plurality of subcarriers to which transmission capacities are allocated, respectively; a light source configured to generate light having a predetermined wavelength; a second modulator configured to modulate the light generated by the light source to an optical signal, based on the second electrical signal modulated by the first modulator; and a processor configured to: measure a first frequency distribution of intensity of the second electrical signal modulated by the first modulator, measure a second frequency distribution of intensity of the optical signal modulated by the second modulator, compare the first frequency distribution and the second frequency distribution, and control modulation characteristics of the second modulator according to a result of comparing the first frequency distribution and the second frequ
    Type: Grant
    Filed: January 12, 2017
    Date of Patent: August 14, 2018
    Assignee: FUJITSU LIMITED
    Inventors: Masato Nishihara, Toshiki Tanaka, Tomoo Takahara, Ryou Okabe
  • Patent number: 10050716
    Abstract: An optical transmission device includes: a first receiver that receives a first optical signal transmitted by a first sub carrier included in a super channel; a second receiver that receives a second optical signal transmitted by a second sub carrier included in the super channel; and an optical delay device that delays the first optical signal, based on path lengths of respective transmission paths along which the first optical signal and the second optical signal are transmitted.
    Type: Grant
    Filed: February 19, 2016
    Date of Patent: August 14, 2018
    Assignee: FUJITSU LIMITED
    Inventors: Kentaro Nakamura, Ryosuke Goto
  • Patent number: 10003409
    Abstract: Provided are methods and systems for receiving and processing optical signals are provided. A dual single side band (SSB) modulation scheme is utilized to take advantage of given wavelengths' bandwidth. Modulation schemes are employed that modulate each SSB with their In-phase (I) and Quadrature (Q) components. The methods and systems discussed perform MIMO de-multiplexing algorithms to remove any imaging components of the left and right SSBs provided by the modulators. Various algorithms can be employed, including but not limited to inserting time interleaved training sequences into the channels of the right and left SSB signals or by employing a constant-modulus-algorithm (CMA) de-multiplexing.
    Type: Grant
    Filed: January 26, 2017
    Date of Patent: June 19, 2018
    Assignee: ZTE Corporation
    Inventors: Jianjun Yu, Yuanquan Wang
  • Patent number: 9989786
    Abstract: An optical transmission device includes an optical modulator and a processor. The optical modulator optically modulates an optical signal with a driving signal to output a modulated optical signal. The processor performs ABC on a bias of the optical modulator, using the modulated optical signal, so as to cause the bias to converge to an optimum point. The processor starts the ABC using a modulated optical signal optically modulated with a QPSK signal at start-up timing, acquires an optimum value that is a bias value when the bias converges to the optimum point, and stops the ABC. After the ABC is stopped, the processor sets the acquired optimum value as an initial value, and restarts the ABC using a modulated optical signal optically modulated with an N-QPSK signal.
    Type: Grant
    Filed: April 3, 2017
    Date of Patent: June 5, 2018
    Assignee: FUJITSU LIMITED
    Inventors: Tomohiro Kaneoka, Hiroshi Ogiwara, Yuichi Akiyama
  • Patent number: 9876577
    Abstract: An optical transmitter includes a discrete multi-tone (DMT) modulation unit that modulates a carrier signal having a specific frequency with an information signal and a carrier signal having a frequency different from the specific frequency with a monitor signal, to generate a DMT modulation signal that multiplexes the information signal and the monitor signal. The optical transmitter includes a laser diode (LD) unit that optically converts the DMT modulation signal to a corresponding optical DMT modulation signal, a frequency extraction unit that extracts a harmonic distortion component of the monitor signal from the optical DMT modulation signal, and a frequency analysis unit. The optical transmitter includes a bias control unit that controls a bias supply unit that adjusts a bias value to be supplied to the LD unit such that the extracted harmonic distortion component of the monitor signal is reduced.
    Type: Grant
    Filed: December 29, 2015
    Date of Patent: January 23, 2018
    Assignee: FUJITSU LIMITED
    Inventors: Toshiki Tanaka, Tomoo Takahara, Masato Nishihara
  • Patent number: 9853738
    Abstract: A distributed traveling-wave Mach-Zehnder modulator driver having a plurality of modulation stages that operate cooperatively (in-phase) to provide a signal suitable for use in a 100 Gb/s optical fiber transmitter at power levels that are compatible with conventional semiconductor devices and conventional semiconductor processing is described.
    Type: Grant
    Filed: August 11, 2016
    Date of Patent: December 26, 2017
    Assignee: Elenion Technologies, LLC
    Inventors: Ran Ding, Thomas Wetteland Baehr-Jones, Michael J. Hochberg, Alexander Rylyakov
  • Patent number: 9838134
    Abstract: The present invention relates to telecommunication techniques and integrated circuit (IC) devices. More specifically, embodiments of the present invention provide an off-quadrature modulation system. Once an off-quadrature modulation position is determined, a ratio between DC power transfer amplitude and dither tone amplitude for a modulator is as a control loop target to stabilize off-quadrature modulation. DC power transfer amplitude is obtained by measuring and sampling the output of an optical modulator. Dither tone amplitude is obtained by measuring and sampling the modulator output and performing calculation using the optical modulator output values and corresponding dither tone values. There are other embodiments as well.
    Type: Grant
    Filed: December 30, 2015
    Date of Patent: December 5, 2017
    Assignee: INPHI CORPORATION
    Inventors: Todd Rope, Radhakrishnan L. Nagarajan, Hari Shankar
  • Patent number: 9755754
    Abstract: A system and method for adaptive equalization in a communication system. The system can include a modulator, a processor coupled to the modulator, and a memory coupled to the processor. The memory can store software instructions that, when executed by the processor, cause the processor to perform operations that can include generating, for each of one or more scan frequencies of interest, an optimal bias setting of the modulator. Data indicating a selection of a range of frequencies to be processed by the communication system can be received at the processor. The operations can include determining, responsive to the receiving, the optimal bias setting corresponding to the selected range of frequencies. A bias of the modulator can be adjusted based on the determined optimal bias setting, the adjusting providing adaptive equalization of the flatness response of the communication system.
    Type: Grant
    Filed: February 24, 2015
    Date of Patent: September 5, 2017
    Assignee: Lockheed Martin Corporation
    Inventors: Andrew F. Schaefer, John C Ceccherelli, Paul T. Coyne, Daniel S. Parsons, Stephen V. Robertson
  • Patent number: 9654225
    Abstract: A high data rate, high sensitivity, low power optical link using low-bandwidth components and low-bandwidth E/O drivers and receivers and method of building same. The method is based on the idea of making the optical part of the link look like a bandwidth limited lossy electrical channel, so that the powerful equalization methods used in the wireline electrical links can be applied to recover the transmitted data in a situation with low bandwidth and/or high loss and strong inter-symbol interference. Linear and non-linear optical channel components, E/O drivers and receivers can benefit from the apparatus and the methods of the invention.
    Type: Grant
    Filed: September 18, 2015
    Date of Patent: May 16, 2017
    Assignee: Elenion Technologies, LLC
    Inventors: Alexander Rylyakov, Richard Younce, Ran Ding, Peter D. Magill, Hao Li, Michael J. J. Hochberg
  • Patent number: 9488854
    Abstract: An optical phase shifter includes an optical waveguide, a plurality of partial phase shifting elements arranged sequentially, and control circuitry electrically coupled to the partial phase shifting elements. The control circuitry is adapted to provide an activating signal to each of the N partial phase shifting elements such that the signal is delayed by a clock cycle between adjacent partial phase shifting elements in the sequence. The transit time for a guided optical pulse train between the input edges of consecutive partial phase shifting elements in the sequence is arranged to be equal to a clock cycle, thereby enabling pipelined processing of the optical pulses.
    Type: Grant
    Filed: April 11, 2013
    Date of Patent: November 8, 2016
    Assignee: Sandia Corporation
    Inventor: William A. Zortman
  • Patent number: 9461770
    Abstract: A multi-channel transceiver using a floating frequency grid for multi-channel, optical communication is presented. Transmitter frequencies are permitted to drift, and a receiver is tuned to compensate for drifts in the transmitter frequencies.
    Type: Grant
    Filed: September 12, 2014
    Date of Patent: October 4, 2016
    Assignee: Skorpios Technologies, Inc.
    Inventors: Robert J. Stone, John Zyskind
  • Patent number: 9344194
    Abstract: A system includes an optical power meter operable to generate an optical power signal corresponding to the optical power of a received output signal generated by an optical IQ-modulator. The system further includes a processor operable to receive the optical power signal and determine, based on a minimization algorithm and the received optical power signal, a first bias voltage to be applied to a first sub-modulator of the optical IQ-modulator and a second bias voltage to be applied to a second sub-modulator of the optical IQ-modulator. The system may also include a peak power meter operable to generate a peak power signal corresponding to the peak power of the received output signal generated by the optical IQ-modulator, wherein the processor is further operable to determine, based on a minimization algorithm and the received peak power signal, a third bias voltage to be applied to a phase shift component of the optical IQ-modulator.
    Type: Grant
    Filed: February 21, 2013
    Date of Patent: May 17, 2016
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 9253730
    Abstract: A transmitter and a receiver for reducing power consumption in a frequency modulation-ultra-wideband (FM-UWB) communication system are provided. The transmitter includes a detector configured to generate a pulse signal when an edge of a digital signal is detected. The transmitter further includes a first modulator configured to modulate the digital signal into a first modulation signal based on a value of the digital signal. The transmitter further includes a second modulator configured to modulate the first modulation signal into a second modulation signal based on a frequency of the first modulation signal when the pulse signal is generated.
    Type: Grant
    Filed: March 19, 2013
    Date of Patent: February 2, 2016
    Assignees: Samsung Electronics Co., Ltd., Tsinghua University
    Inventors: Woogeun Rhee, Bo Zhou, Jong-jin Kim, Dong-wook Kim, Zhihua Wang
  • Patent number: 9217908
    Abstract: An optical modulator includes main input and output ports; first and second Mach-Zehnder modulators; a first branching waveguide optically coupling the main input port to the first and second Mach-Zehnder modulators; a first driver circuit connected to the first Mach-Zehnder modulator, the first driver circuit generating a first drive signal having a first amplitude at a first bias point; and a second driver circuit connected to the second Mach-Zehnder modulator, the second driver circuit generating a second drive signal having a second amplitude at a second bias point. The first and second drive signals satisfy at least one of a first condition and a second condition. The first condition is that the first amplitude differs from the second amplitude. The second condition is that the first bias point differs from the second bias point.
    Type: Grant
    Filed: April 11, 2014
    Date of Patent: December 22, 2015
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventor: Naoya Kono
  • Patent number: 9130680
    Abstract: An optical transmitter includes: an optical modulator including a first modulation unit and a second modulation unit respectively configured to propagate a first optical signal and a second optical signal that are obtained by splitting input light; a signal generator configured to generate a first drive signal and a second drive signal that are respectively supplied to the first modulation unit and the second modulation unit; a phase controller configured to control a phase difference between the first optical signal and the second optical signal in the optical modulator; and a phase difference detector configured to detect the phase difference between the first optical signal and the second optical signal controlled by the phase controller. The signal generator generates the first drive signal and the second drive signal based on the phase difference detected by the phase difference detector.
    Type: Grant
    Filed: December 18, 2013
    Date of Patent: September 8, 2015
    Assignee: FUJITSU LIMITED
    Inventors: Yuichi Akiyama, Takeshi Hoshida, Tamotsu Akashi, Yoshio Sakai
  • Patent number: 9124364
    Abstract: A method of controlling an optical transmitter having a Dual Parallel Mach-Zehnder (DPMZ) modulator. An I-Q power balance between respective branches of the DPMZ modulator is detected, and at least one parameter of the DPMZ modulator is adjusted to drive the I-Q power balance to a predetermined target value. An optical transmitter may have Quad Parallel Mach-Zehnder (QPMZ) modulator having a pair of parallel DPMZ modulators for modulating respective X- and Y-polarization lights. In such cases, an X-Y power imbalance between the two polarization lights is detected, and at least one parameter of the QPMZ modulator is adjusted to drive the X-Y power imbalance to a predetermined value.
    Type: Grant
    Filed: May 30, 2012
    Date of Patent: September 1, 2015
    Assignee: CIENA CORPORATION
    Inventors: Mohammad Sotoodeh, Gary Mak, Yves Beaulieu
  • Patent number: 9089084
    Abstract: A method to control an optical transceiver, in particular, to drive an LD installed within the optical transceiver is described. The LD in the bias current thereof is determined by the automatic power control (APC) loop to keep an average of the optical output power. The modulation current is determined by a feedback loop to keep the extinction ratio (ER) in a preset range. The initial condition of the modulation current for the feedback loop is set by T-Im characteristic. The T-Im characteristic is first derived based on data measured in a status of the LD not installed in the transceiver. The T-Im characteristic is revised timely by the modulation current practically obtained for the optical transceiver.
    Type: Grant
    Filed: February 21, 2013
    Date of Patent: July 21, 2015
    Assignee: Sumitomo Electric Device Innovations, Inc.
    Inventors: Toru Ukai, Moriyasu Ichino, Tadashi Sakai
  • Patent number: 9037003
    Abstract: A signal transmission device drives a light-emitting element and outputs an optical signal depending on a data signal from an electronic device. The device includes an element driving portion which supplies a driving current to the light-emitting element, wherein the driving current is obtained by superimposing a modulation current on a bias current, the modulation current being dependent on the data signal indicating emitting information of the light-emitting element. A temperature compensation portion of the device controls the bias current and the modulation current depending on the temperature so that a temperature-current characteristic of the light-emitting element is reproduced based on the voltage which is dependent on the temperature and the voltage which is independent from the temperature, thereby performing current control depending on the temperature.
    Type: Grant
    Filed: March 26, 2013
    Date of Patent: May 19, 2015
    Assignee: YAZAKI CORPORATION
    Inventors: Chiemi Yamagata, Atsushi Nakata, Kengo Noguchi, Yukio Akazawa
  • Patent number: 9020363
    Abstract: After a startup of an optical transmitter, a control is started in such a way that a modulation amplitude of a driving signal of a phase modulator is set as 0, and that an operational point of a bias voltage is set as the lowest point of light transmission characteristics of the phase modulator. When the operational point of the bias voltage reaches the lowest point, the modulation amplitude of the driving signal is gradually increased from 0 to 2V?.
    Type: Grant
    Filed: October 26, 2012
    Date of Patent: April 28, 2015
    Assignee: Fujitsu Optical Components Limited
    Inventor: Shuichi Yasuda
  • Patent number: 9020361
    Abstract: An optical signal transmitter of the present invention includes: two phase modulating portions; a phase shifter which displaces carrier phases of two output lights from the phase modulating portions by ?/2; a multiplexing portion which multiplexes two signal lights, carrier phases of the two signal lights being made orthogonal to each other by the phase shifter; a drive signal electrode portion which supplies a differential data signal to each of four paths of interference optical waveguides, each of the two phase modulating portions having the interference optical waveguides, the differential data signal having an amplitude which is equal to a half-wave voltage V? of the two phase modulating portions; a drive amplifier which amplifies the differential data signal to be supplied to each of the four paths of the interference optical waveguides; a data bias electrode portion which supplies a total of four data bias voltages to two arms, each of the two phase modulating portions having the two arms; an orthogona
    Type: Grant
    Filed: September 7, 2010
    Date of Patent: April 28, 2015
    Assignees: Nippon Telegraph and Telephone Corporation, NTT Electronics Corporation
    Inventors: Hiroto Kawakami, Eiji Yoshida, Masahiro Tachibana
  • Patent number: 9014572
    Abstract: An optical transmitter includes an optical modulator having first and second waveguides to modulate carrier light at each of the waveguides using a driving signal with 2*n intensity levels (n is an integer 1 or greater); and a phase shifter to cause a phase difference between a first optical signal and a second optical signal output from the first waveguide and the second waveguide, respectively. A photodetector converts a portion of a multilevel optical modulation signal acquired by combining the first optical signal and the second optical signals into an electrical signal. A monitor detects a change in an alternating current component in the detected modulation signal. A controller controls at least one of a first bias voltage and a second bias voltage being supplied to the first waveguide and the second waveguide, respectively, so as to increase the power value of the alternating current component.
    Type: Grant
    Filed: March 30, 2012
    Date of Patent: April 21, 2015
    Assignee: Fujitsu Limited
    Inventor: Yuichi Akiyama
  • Patent number: 9002145
    Abstract: The optical frequency comb generating device having two optical modulation parts 41 and 42 independently modulating optical waves propagating in two branch waveguides and a phase regulator 43 controlling a phase difference between the optical waves includes amplitude adjusting means 22 for adjusting a voltage amplitude of the RF signal supplied to at least one of the optical modulation parts, monitoring means 21 for monitoring the intensity Pout of the output light beam, and a bias control circuit 20 that controls the amplitude adjusting means to change a difference in voltage amplitude between the RF signals supplied to each optical modulation part, that detects a variation of the output light beam corresponding to the variation of the difference in voltage amplitude from the output signal of the monitoring means, and that controls the phase regulator on the basis of the detection result to adjust the phase difference.
    Type: Grant
    Filed: February 21, 2011
    Date of Patent: April 7, 2015
    Assignee: Sumitomo Osaka Cement Co., Ltd.
    Inventors: Masaaki Sudo, Masahito Mure
  • Patent number: 8989601
    Abstract: A modular hub driver architecture may include a multi-delay block configured to provide an enhanced delay match among N distinct stages of a distributed modulating electro-optical interface core. The electro-optical multi-core modulator driver may include an input impedance matching stage and a pre-conditioning circuit configured to generate a number M, an integer divisor of N, of delayed replicas of an electrical modulating signal. The electro-optical multi-core modulator may include an array of M launch buffers of the replica signals, and an array of M multi-delay blocks, each including delay circuit modules differently cascaded on distinct signal paths, and configured to receive, at respective inputs, the M replica signals and to output N/M differently delayed replicas of the input signals, each driving a correspondent output stage of one on the N electro-optical interface cores.
    Type: Grant
    Filed: October 1, 2013
    Date of Patent: March 24, 2015
    Assignee: STMicroelectronics S.R.L.
    Inventors: Enrico Stefano Temporiti Milani, Matteo Repossi, Daniele Baldi
  • Patent number: 8989600
    Abstract: A modulating apparatus includes a branch that branches input light; a first modulating unit that modulates the phase of a first branch obtained by the branch; a second modulating unit that modulates a second branch obtained by the branch; a third modulating unit that is connected in series to the first modulating unit, transmits the first branch without branching the first branch, modulates the phase of light transmitted by controlling a refractive index of the light transmitted; a fourth modulating unit that is connected in series to the second modulating unit, transmits the second branch without branching the second branch, and modulates the phase of a light transmitted by controlling a refractive index of the light transmitted; and a coupler that couples the first branch modulated by the first and the third modulating units and the second branch modulated by the second and the fourth modulating units, at different intensities.
    Type: Grant
    Filed: September 27, 2013
    Date of Patent: March 24, 2015
    Assignee: Fujitsu Optical Components Limited
    Inventor: Kenichi Nakamoto
  • Patent number: 8983305
    Abstract: The present invention provides a method and an apparatus for controlling a phase delay offset point of a modulator. The method comprises: acquiring backlight detection current signals output from a modulator in different working states, and determining harmonic amplitude values of the backlight detection current signals corresponding to the different working states; determining a detection value of a phase delay offset point corresponding to the modulator according to the determined harmonic amplitude values; comparing the detection value with a set target value of the phase delay offset point, and controlling a position of the phase delay offset point corresponding to the modulator according to the comparison result. The accuracy of controlling the position of the phase delay offset point of the modulator and the performance of the Differential Quadrature Phase Shift Keying (DQPSK) modulation system are improved through the technical solution.
    Type: Grant
    Filed: August 17, 2010
    Date of Patent: March 17, 2015
    Assignee: ZTE Corporation
    Inventors: Hong Yi, Jianhong Chen
  • Patent number: 8971725
    Abstract: An optical communication module includes a laser that emits laser light, and an electro-absorber that absorbs the laser light, which is emitted from the laser, according to a voltage modulated based on a modulating signal and a bias voltage. The optical communication module detects data that varies correlatively with the temperature of the electro-absorber, and sets the bias voltage, which is associated with the detected data, on the basis of relational data specifying at least the relationship between the bias voltage and the data.
    Type: Grant
    Filed: October 12, 2010
    Date of Patent: March 3, 2015
    Assignee: Oclaro Japan, Inc.
    Inventors: Satoshi Motohiro, Kohsuke Shimodate, Masahiro Hirai
  • Patent number: 8958705
    Abstract: A method of operating an optical amplifier includes determining a gain of the optical amplifier and providing a modulator drive signal to an optical signal source. The modulator drive signal is a function of the gain of the optical amplifier. The method also includes producing an input optical signal using the optical signal source. The input optical signal includes a first plurality of pulses, each of the first plurality of pulses having an amplitude related to the modulator drive signal. The method further includes coupling the input optical signal to the optical amplifier and amplifying the input optical signal using the optical amplifier to produce an output optical signal including a second plurality of pulses.
    Type: Grant
    Filed: January 13, 2012
    Date of Patent: February 17, 2015
    Assignee: ESI-Pyrophotonics Lasers Inc.
    Inventors: Guillaume Blanchette, Richard Murison, Benoit Reid
  • Patent number: 8948608
    Abstract: An optical modulator device directly-coupled to a driver circuit device. The optical modulator device can include a transmission line electrically coupled to an internal VDD, a first electrode electrically coupled to the transmission line, a second electrode electrically coupled to the first electrode and the transmission line. A wave guide can be operably coupled to the first and second electrodes, and a driver circuit device can be directly coupled to the transmission line and the first and second electrodes. This optical modulator and the driver circuit device can be configured without back termination.
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: February 3, 2015
    Assignee: Inphi Corporation
    Inventor: Carl Pobanz
  • Patent number: 8947766
    Abstract: An optical device comprising a tunable optical frequency comb generator. The comb generator includes an interferometer, and an optical feed-back loop waveguide.
    Type: Grant
    Filed: May 5, 2014
    Date of Patent: February 3, 2015
    Assignee: Alcatel Lucent
    Inventors: Long L. Chen, Christopher R. Doerr, Nicolas Dupuis
  • Patent number: 8929745
    Abstract: A first clock modulator branches a light beam, varies a phase difference of the resulting light beams according to a first clock, and causes interference of the light beams. A second clock modulator branches a light beam from the first clock modulator and synchronized with the first clock, varies a phase difference of the resulting light beams according to a second clock, and causes interference of the light beams. A third clock modulator branches a light beam from the first clock modulator and inversely synchronized with the first clock, varies a phase difference of the resulting light beams according to a third clock, and causes interference of the light beams. The second clock and the first clock have identical cycles and differing phases. The third clock and the second clock have phases that differ by a 1/2 cycle. Four data modulators modulate the light beams from the clock modulators.
    Type: Grant
    Filed: June 24, 2013
    Date of Patent: January 6, 2015
    Assignee: Fujitsu Optical Components Limited
    Inventor: Toru Yamazaki
  • Patent number: 8909067
    Abstract: The I phase modulator modulates a phase based on the bias voltage in which a first modulation signal and a first pilot signal are inherent and the Q phase modulator modulates a phase based on the bias voltage in which a second pilot signal different from the first pilot signal and a second modulation signal are inherent. A time-average power synchronous detection unit detects an optical power at a timing at which the positivity and negativity of the voltages of both pilot signals become the same, and an optical power when the positivity and negativity of the voltages of both pilot signals are opposite. The bias voltage control unit controls the bias voltage so that the difference between both the optical powers becomes small based on the detection result of the time-average power synchronous detection unit.
    Type: Grant
    Filed: May 14, 2012
    Date of Patent: December 9, 2014
    Assignee: Oclaro Japan, Inc.
    Inventors: Kouji Takeguchi, Shigehiro Takashima, Taichi Kogure, Hirofumi Nakagawa, Saki Narisawa
  • Patent number: 8909046
    Abstract: A system for transporting a plurality of analog and/or digital signals over an optical fiber can include one or more master modems for modulating digital signals and/or RF inserters modulating video signals. The RF signals from the modem(s)/RF inserters are up-converted resulting in frequency bands that are non-overlapping and are spaced apart within a single sub-octave. The sub-octave signal is then converted into an optical signal and directed onto an end of an optical fiber. At the downstream end of the optical fiber, the received optical signal is converted to an RF signal at an optical receiver. The RF signal is then filtered, down-converted and directed to a selected coaxial distribution unit. From the coaxial distribution unit, the RF signal is demodulated, e.g. at a slave modem, to recover the initial analog and/or digital signal.
    Type: Grant
    Filed: October 4, 2012
    Date of Patent: December 9, 2014
    Assignee: Titan Photonics
    Inventors: Chen-Kuo Sun, Peter H. Wolff
  • Patent number: 8897656
    Abstract: A system may include one or more devices that may be used to simultaneously measure and modulate phases of a many-channel optical system relative to a high frequency optical carrier. This device may be constructed using analog-to-digital converters, comparators, and distributed timers. A digital processor may be used to recover phase information from the measurements and to calculate an error compared to desired phase. The processor may then apply feedback to a phase modulator to correct the phase.
    Type: Grant
    Filed: July 7, 2011
    Date of Patent: November 25, 2014
    Assignee: EM Photonics, Inc.
    Inventors: Petersen F. Curt, Michael R. Bodnar
  • Patent number: 8891968
    Abstract: A method and apparatus for loading, detecting, and monitoring channel-associated signals are provided. Channel-associated signals are identified with spread spectrum codes in the electrical domain, and after being modulated to an optical service signal at respective loading points separately, the channel-associated identification signals are transmitted in the optical channel along with the optical signal. At any downstream detecting point, passing optical signals can be converted through photoelectric conversion, and the channel-associated identification signals are de-spread. By detecting the channel-associated signals, it is possible to learn about whether the upstream loading point work normally, whether the optical channel operates normally, etc., and thereby to find possible failures, solve problems, and monitor quality parameters of optical signals in real time, and improve reliability of the optical signal transmission.
    Type: Grant
    Filed: December 2, 2011
    Date of Patent: November 18, 2014
    Assignee: Huawei Technologies Co., Ltd.
    Inventor: Congqi Li
  • Patent number: 8891959
    Abstract: An optical modulation device includes a generating circuit that generates a low-frequency signal, an average value of amplitude as an alternating-current component of the low-frequency signal being different from a center value of the amplitude of the low-frequency signal, a superimposing unit that superimposes the low-frequency signal on a data signal, an optical modulator that modulates, using the superimposition of the low-frequency signal by the superimposing unit, light from a light source and outputs a light signal, a calculating circuit that calculates an amplitude average value and an amplitude center value of a low-frequency component obtained from the light signal output by the optical modulator, and a controller that controls a bias voltage of the optical modulator such that the amplitude average value is brought closer to the amplitude center value of the frequency component calculated by the calculating circuit.
    Type: Grant
    Filed: May 29, 2012
    Date of Patent: November 18, 2014
    Assignee: Fujitsu Limited
    Inventor: Yuji Ishii
  • Patent number: 8879921
    Abstract: The invention relates to an apparatus and a method for modulation of an optical signal with a data signal, said apparatus (6) comprising a configurable digital encoding unit (8) encoding data of said data signal to provide an encoded modulation control signal (EMCS), and a signal modulation unit (9) modulating said optical signal with respect to its signal phase and/or signal amplitude in orthogonal polarization directions in response to said encoded modulation control signal (EMCS) to generate a multi-dimensional optical signal vector.
    Type: Grant
    Filed: May 31, 2011
    Date of Patent: November 4, 2014
    Assignee: Adva Optical Networking SE
    Inventor: Michael Eiselt
  • Patent number: 8849129
    Abstract: A DP-QPSK optical transmitter includes an outer MZM comprising a first parent MZM comprising a first child MZM and a second child MZM that modulates a QPSK signal with a first polarization. A second parent MZM includes a first child MZM and a second child MZM that modulates a QPSK signal with a second polarization. The outer Mach-Zehnder modulator multiplexes the first and second polarization embedded into a dual-polarization QPSK signal generation. A first optical detector detects the QPSK signal generated by the first parent MZM with the first polarization. A second optical detector optical detects the QPSK signal generated by the second parent Mach-Zehnder modulator with the second polarization. A bias control circuit generates bias signals on at least one output that stabilize the DP-QPSK signal in response to signals generated by the first and second optical detector using electrical time division multiplexing.
    Type: Grant
    Filed: July 20, 2012
    Date of Patent: September 30, 2014
    Assignee: Finisar Corporation
    Inventors: Suhas P. Bhandare, Heider N. Ereifej, Kyu Kim, Mark Colyar
  • Patent number: 8843001
    Abstract: An optical transmitter is disclosed. An optical modulator outputs an optical signal by modulating light being input, and has an optical absorption characteristic which changes a degree of optical absorption depending on a bias voltage being applied and includes a first characteristic region and a second characteristic region in which the degree of the optical absorption is greater than the first characteristic region. An power source applies an electric field generated by applying a predetermined shutdown bias voltage corresponding to the second characteristic region to electrodes provided in two interference optical guides formed in the optical modulator, when an output of the optical signal from the optical modulator is shut down to be less than or equal to a desired amount.
    Type: Grant
    Filed: October 30, 2011
    Date of Patent: September 23, 2014
    Assignee: Fujitsu Optical Components Limited
    Inventor: Ryoji Nagase
  • Patent number: 8842998
    Abstract: Apparatuses and methods for modulating an optical signal are disclosed. One embodiment is a method comprising: phase modulating a slave laser which is injection locked to a master laser to produce an arcsine phase modulated optical signal, and combining the arcsine phase modulated optical signal with an output optical signal from the master laser.
    Type: Grant
    Filed: February 5, 2010
    Date of Patent: September 23, 2014
    Assignee: University of Central Florida Research Foundation, Inc.
    Inventors: Peter J. Delfyett, Nazanin Hoghooghi, Josue Davila-Rodriguez, Michael Goldblatt
  • Patent number: 8824901
    Abstract: A multi-mode optoelectronic oscillator (MM-OEO) includes an OEO cavity having an input for receiving an RF signal and an RF output. The OEO cavity includes a) a first laser having a first laser output, a second laser having a second laser output, b) a modulator having i) a first input coupled to the first laser output, ii) a second input coupled to the second laser output, iii) a third input, iv) a first modulator output, and v) a second modulator output, c) a semiconductor optical amplifier (SOA) having an input coupled to the first modulator output and having an SOA amplified output, d) a photodetector coupled to the SOA amplified output and having an output, and e) a coupler having an input coupled to the photodetector output and having a first output coupled to the third modulator input and a second output, whereby an amplified RF signal is produced at the OEO RF output.
    Type: Grant
    Filed: September 14, 2012
    Date of Patent: September 2, 2014
    Assignee: The United States of America, as represented by the Secretary of the Navy
    Inventors: Preetpaul S Devgan, Vincent J Urick, Keith J Williams
  • Patent number: 8818193
    Abstract: An embodiment of the invention includes a tunable optical dispersion compensator (TODC) comprising a first beam displacer on an optical path, wherein the first beam displacer separates an optical signal into a first beam and a second beam, and one or more polarizing beam splitters on the optical path, wherein the one or more polarizing beam splitters keep the first beam and the second beam on the optical path. The TODC also comprises one or more etalons on the optical path, wherein the one or more etalons are tunable to introduce a group delay in the first beam and the second beam, and a reflecting mirror on the optical path, wherein the reflecting mirror returns the optical signal back along the optical path. The TODC further comprises a second beam displacer, wherein the second beam displacer combines the first beam and the second beam into an output optical signal.
    Type: Grant
    Filed: September 29, 2009
    Date of Patent: August 26, 2014
    Assignee: Finisar Corporation
    Inventors: Fan Chen, Yongkang Hu, Zhenli Wen, Dongshen Han, Fahua Lan, Kevin Dapeng Zhang
  • Patent number: 8811821
    Abstract: An optical transmitter includes: a selection circuit; a signal processing circuit; an optical modulator; and a control circuit. The selection circuit selects signal components on the sides of the maximum and minimum values in a multivalued electrical signal for modulation of a transmitting signal. The signal processing circuit generates a multivalued electrical signal into which the transmitting signal is converted by a combination of a superimposed signal that a low-frequency wave is superimposed on the signal components and a signal having a plurality of intermediate amplitude values on which the low-frequency wave is not superimposed. The optical modulator modulates a carrier light on the basis of the multivalued electrical signal. The control circuit controls the reference amplitude value or amplitude of the multivalued electrical signal on the basis of the low-frequency components contained in a modulated optical signal.
    Type: Grant
    Filed: August 14, 2012
    Date of Patent: August 19, 2014
    Assignee: Fujitsu Optical Components Limited
    Inventor: Hiroshi Nishimoto
  • Patent number: 8798482
    Abstract: An infrared transmitter is obtained that transmits a signal by changing a luminance of an infrared emitting LED, the infrared transmitter including: a transmission signal generating unit; a biasing voltage generating unit that generates a biasing voltage according to a magnitude of a transmission signal; a signal/voltage mixing unit that mixes the transmission signal and the biasing voltage; and a voltage-current conversion unit that converts a voltage into a current, in which the LED is driven by the current obtained by the conversion in the voltage-current conversion unit, so that power consumption efficiency can be improved.
    Type: Grant
    Filed: September 11, 2008
    Date of Patent: August 5, 2014
    Assignee: Kabushiki Kaisha Audio-Technica
    Inventor: Tatsuji Harima
  • Patent number: 8781337
    Abstract: A method of phase modulating optical radiation by the steps of phase modulating the optical radiation by using a modulator having an extinction ratio in order to provide a multilevel phase shift key signal, and applying to each optical pulse a phase-shift having an absolute value depending on the extinction ratio and a sign depending, for each of the optical pulses, on the respective optical phase value. An apparatus implementing the method is also disclosed.
    Type: Grant
    Filed: September 6, 2011
    Date of Patent: July 15, 2014
    Assignee: Google Inc.
    Inventors: Pierpaolo Boffi, Lucia Marazzi, Mario Martinelli, Livio Paradiso, Paola Parolari
  • Patent number: 8774645
    Abstract: Method and apparatus for controlling bias point of DQPSK demodulator are disclosed. The method comprises: step 1: respectively applying first and second bias voltages to I-path and Q-path, and applying identical pilot voltage signals to I-path and Q-path (S202); step 2: executing filtering processing on I-path and Q-path differential current signals collected by balance receiver and determining ?Iand ?Q (S204); step 3: performing feedback control to first and second bias voltages respectively according to ?I and ?Q so that ?I and ?Q respectively reaches expected bias point values of I-path and Q-path (S206); executing step 2 and 3 cyclically at preset regular intervals (S208), so that ?I and ?Q remains consistently the expected bias point values of I-path and Q-path. The solution enables bias point of DQPSK demodulator to be locked at any expected bias point value, facilitates realization of digitization, and is not easily influenced.
    Type: Grant
    Filed: August 20, 2010
    Date of Patent: July 8, 2014
    Assignee: ZTE Corporation
    Inventors: Jianhua Chen, Hong Yi
  • Patent number: 8774568
    Abstract: Provided is an optical module. The optical module includes: an optical bench having a first trench of a first depth and a second trench of a second depth that is less than the first depth; a lens in the first trench of the optical bench; at least one semiconductor chip in the second trench of the optical bench; and a flexible printed circuit board covering an upper surface of the optical bench except for the first and second trenches, wherein the optical bench is a metal optical bench or a silicon optical bench.
    Type: Grant
    Filed: June 7, 2011
    Date of Patent: July 8, 2014
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Young-Tak Han, Jang Uk Shin, Sang-Pil Han, Sang Ho Park, Yongsoon Baek
  • Patent number: 8760752
    Abstract: An optical device comprising a tunable optical frequency comb generator. The comb generator includes an interferometer, and an optical feed-back loop waveguide.
    Type: Grant
    Filed: March 8, 2011
    Date of Patent: June 24, 2014
    Assignee: Alcatel Lucent
    Inventors: Long L. Chen, Christopher R. Doerr, Nicolas Dupuis
  • Patent number: 8761613
    Abstract: This invention relates to external modulator monitoring device and method for monitoring an external modulator. The external modulator monitoring device includes a mixing unit for mixing optical signals modulated by the external modulator and optical signals not modulated by the external modulator, so as to obtain multiple branches of mixed optical signals; an electrical differential unit for converting the multiple branches of mixed optical signals into corresponding multiple branches of electrical signals, and performing a differential processing on voltages of the multiple branches of electrical signals to obtain differential signals; and a power detection unit for detecting power of the differential signals.
    Type: Grant
    Filed: October 4, 2010
    Date of Patent: June 24, 2014
    Assignee: Fujitsu Limited
    Inventors: Liang Dou, Zhenning Tao