For Wavelength Control Patents (Class 398/196)
  • Patent number: 10187172
    Abstract: A processor of an optical transport apparatus is configured to transport an optical multiplexed signal between the optical transport apparatus and a counterpart apparatus by using a plurality of communication units; transmit an arbitrary optical wavelength from the optical multiplexed signal passing through ports by using a wavelength selective switch that has the ports respectively connected to the communication units; control a radio unit in the counterpart apparatus so as to change a frequency of the radio signal in the specified optical wavelength; and change a transmission band of the port through which the optical wavelength passes, according to a change of the frequency of the radio signal. The processor is configured to control an optical transmission unit of the counterpart apparatus so as to change a center wavelength of an optical wavelength passing through the port to a center wavelength of the changed transmission band of the port.
    Type: Grant
    Filed: February 13, 2017
    Date of Patent: January 22, 2019
    Assignee: FUJITSU LIMITED
    Inventors: Goji Nakagawa, Yasuhiko Aoki, Kyosuke Sone
  • Patent number: 10075256
    Abstract: A method of automatically tuning subcarriers of a superchannel transmission. The method comprises determining (71) a received parameter of transmission quality of one or more of the plurality of subcarriers. The method further comprises tuning (72) a frequency of the one or more subcarrier based on the determined parameter of the transmission quality.
    Type: Grant
    Filed: August 16, 2013
    Date of Patent: September 11, 2018
    Assignee: Telefonaktiebolaget L M Ericsson (PUBL)
    Inventors: Roberto Magri, Fabio Cavaliere
  • Patent number: 9768906
    Abstract: An optical transmission apparatus includes: a plurality of optical transmitters configured to transmit optical signals having variable wavelengths, respectively; a multiplexer configured to wavelength-multiplex the optical signals transmitted from the plurality of optical transmitters in a transmission band of an optical device through which the optical signals is transmitted; and a controller configured to control, in response to nonexistence of an optical signal having a second wavelength adjacent to a first wavelength closest to an outer edge of the transmission band in the optical signals, an optical transmitter corresponding to the first wavelength so as to shift the first wavelength in a direction toward the second wavelength.
    Type: Grant
    Filed: January 20, 2016
    Date of Patent: September 19, 2017
    Assignee: FUJITSU LIMITED
    Inventors: Hisayuki Ojima, Taku Saito
  • Patent number: 9520949
    Abstract: Various apparatuses, circuits, systems, and methods for optical communication are disclosed. In some implementations an optical transmitter includes an optical data port configured to engage an optical fiber. The optical transmitter also includes a plurality of lasers coupled to the optical data port and configured and arranged to transmit respective optical signals over the optical fiber via the optical data port when selected. A control circuit of the optical transmitter is configured to receive an input data signal and encode the input data signal for transmission over the optical fiber by selecting one or more of the plurality of lasers at a time. The control circuit is configured to select one or more of the plurality of lasers at a time according to one of a frequency modulation encoding algorithm or an amplitude modulation encoding algorithm.
    Type: Grant
    Filed: June 5, 2014
    Date of Patent: December 13, 2016
    Assignee: XILINX, INC.
    Inventors: Stephen M. Trimberger, Austin H. Lesea
  • Patent number: 9407395
    Abstract: A remote node (RN) comprises a downstream port, a wavelength multiplexer (WM) coupled to the downstream port and comprising ports for passing optical waves, an optical rotator coupled to the WM, and a mirror coupled to the optical rotator, wherein the WM, the optical rotator, and the mirror are part of a wavelength tuning scheme. An apparatus comprises a tunable transmitter, a polarization beam splitter (PBS) coupled to the tunable transmitter, a filter coupled to the PBS, a receiver coupled to the filter, a photodiode (PD) coupled to the PBS, and a processor coupled to the tunable transmitter and the PD. An apparatus comprises a tunable transmitter configured to transmit a first optical wave, a filter configured to receive a first reflected optical wave associated with the first optical wave, and a processor configured to tune the tunable transmitter based on the first reflected optical wave.
    Type: Grant
    Filed: July 3, 2014
    Date of Patent: August 2, 2016
    Assignee: Futurewei Technologies, Inc.
    Inventors: Frank J. Effenberger, Huafeng Lin, Lei Zong, Feng Wang
  • Patent number: 9287986
    Abstract: A large capacity optical transceiver module includes: an optical transmitter configured to convert electric signals input from an external source into optical signals to transmit the converted signals, in which the electric signals are directly modulated into optical signals in a plurality of sub groups to be multiplexed; and an optical receiver configured to receive optical signals from the external source, and to convert the received optical signals into electric signals to output the converted signals, in which the optical signals are demultiplexed in a plurality of sub groups to be converted into electric signals.
    Type: Grant
    Filed: April 16, 2014
    Date of Patent: March 15, 2016
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Joon Ki Lee, Sae-Kyoung Kang, Joon Young Huh
  • Patent number: 9178645
    Abstract: A wavelength path reallocation method in a path reallocation apparatus for reallocating a wavelength path set in a communication network, including: a wavelength path designing step in which a wavelength path designing unit designs a reallocation destination wavelength path by performing calculation such that the number of use frequency regions in the communication network becomes smaller than a corresponding value before reallocation; and a wavelength path setting step in which a wavelength path setting unit changes a reallocation target wavelength path to the reallocation destination wavelength path by using free wavelength.
    Type: Grant
    Filed: October 21, 2011
    Date of Patent: November 3, 2015
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Akihiro Kadohata, Akira Hirano, Yoshiaki Sone, Yukio Tsukishima, Takafumi Tanaka
  • Patent number: 9124382
    Abstract: A transmission device includes: a wavelength detector configured to detect a first wavelength of a first optical signal; a wavelength selective switch to which the first optical signal is input; and a controller configured to detect a direction toward which a central wavelength of a passband of the wavelength selective switch is shifted from the first wavelength detected by the wavelength detector and to control the wavelength selective switch so as to increase a width of the passband toward an opposite direction of the direction toward which the central wavelength of the passband is shifted from the first wavelength.
    Type: Grant
    Filed: October 4, 2013
    Date of Patent: September 1, 2015
    Assignee: FUJITSU LIMITED
    Inventors: Kenichi Kaburagi, Hiroaki Tomofuji
  • 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: 9031412
    Abstract: A coolerless photonic integrated circuit (PIC), such as a semiconductor electro-absorption modulator/laser (EML) or a coolerless optical transmitter photonic integrated circuit (TxPIC), may be operated over a wide temperature range at temperatures higher then room temperature without the need for ambient cooling or hermetic packaging. Since there is large scale integration of N optical transmission signal WDM channels on a TxPIC chip, a new DWDM system approach with novel sensing schemes and adaptive algorithms provides intelligent control of the PIC to optimize its performance and to allow optical transmitter and receiver modules in DWDM systems to operate uncooled. Moreover, the wavelength grid of the on-chip channel laser sources may thermally float within a WDM wavelength band where the individual emission wavelengths of the laser sources are not fixed to wavelength peaks along a standardized wavelength grid but rather may move about with changes in ambient temperature.
    Type: Grant
    Filed: November 4, 2009
    Date of Patent: May 12, 2015
    Assignee: Infinera Corporation
    Inventors: Radhakrishnan L. Nagarajan, Fred A. Kish, Jr., David F. Welch, Drew D. Perkins, Masaki Kato
  • Patent number: 8995828
    Abstract: An optical transmission device includes an extractor that extracts respective optical signals from optical signals multiplexed from a plurality of optical signals of different wavelengths, a detector that detects wavelengths of the extracted respective optical signals, a storage that stores the wavelengths of the detected respective optical signals, and a processor that is operative to derive trends in wavelength variation of the respective optical signals based on the detected respective optical signals and the respective optical signals stored in the storage, and determines that either one or both of the extractor and the detector cause the wavelengths to be varied when the trends in wavelength variation of two or more wavelengths are the same.
    Type: Grant
    Filed: October 25, 2011
    Date of Patent: March 31, 2015
    Assignee: Fujitsu Limited
    Inventors: Yuichi Suzuki, Toshihiro Ohtani
  • Patent number: 8983306
    Abstract: A WDM device having a controller that individually controls the operating parameters of tunable lasers and the temperatures of an optical multiplexer and etalon. The device employs a spectral analyzer to measure the spectral composition of the optical output signal produced by the device. Based on the analyses of the measured spectral composition, the controller sets the temperatures of the tunable lasers, optical multiplexer, and optical etalon to values that cause: (i) middle frequencies of transmission bands of the optical multiplexer to be spectrally aligned with the corresponding frequencies of the specified frequency grid, (ii) each laser line to be properly positioned within the corresponding transmission band, and (iii) transmission resonances of the optical etalon to be properly positioned with respect to the laser lines.
    Type: Grant
    Filed: November 11, 2011
    Date of Patent: March 17, 2015
    Assignee: Alcatel Lucent
    Inventors: Pietro A. G. Bernasconi, David T. Neilson
  • Patent number: 8934787
    Abstract: An apparatus comprising a plurality of optical transmitters and a wavelength locker shared by the plurality of optical transmitters. A periodic transmission filter used for wavelength locker operations is in a network communication path and shapes optical transmissions from the plurality of optical transmitters to a network. An apparatus comprising at least one processor configured to receive a pre-filter signal corresponding to part of an optical signal comprising a pilot tone and to receive a post-filter signal corresponding to a part of the optical signal that passes through a period transmission filter, wherein a filtered part of the optical signal is directed into a network. The processor is also configured to perform wavelength locking based on a quadrature detection technique that aligns an adiabatic logical one position of a modulated transmission signal with a spectral transmission peak of the period transmission filter.
    Type: Grant
    Filed: September 29, 2011
    Date of Patent: January 13, 2015
    Assignee: Futurewei Technologies, Inc.
    Inventors: Xiao A. Shen, Tongqing Wang, Hongbing Lie, Yu Sheng Bai
  • Patent number: 8929748
    Abstract: The disclosure relates to a tunable 50 GHz and 100 GHz channel spacing DWDM transceiver, and methods of making and using the same. The transceiver comprises an electro-absorption modulation laser (EML), a system board configured to compare a preset wavelength with an actual emission wavelength of the EML, a microcontroller and one or more associated registers configured to communicate with the system board, a temperature controlling circuit configured to stabilize the actual emission wavelength of the EML; and a wavelength meter connected to the output of the EML and having an output connected to the system board. The system board may be configured to provide a feedback loop from the EML to the microcontroller. The transceiver, suitable for 50 GHz channel spacing standards, can be made from existing standard transceivers and can switch between 50 GHz and 100 GHz channel spacing modes.
    Type: Grant
    Filed: March 17, 2011
    Date of Patent: January 6, 2015
    Assignee: Source Photonics
    Inventors: Zhaoyang Hu, Qing Xiao, Meiling Lu, Yan Chen, Thomas Liljeberg
  • Patent number: 8926601
    Abstract: An improved system for safe and efficient generation of plasmas and vapors bubbles with continuous wave radiations and low levels of power densities, sufficient to treat medical pathologies and to avoid the creation damage to healthy tissue is provided. Transmission means in different configurations are used to achieve a high absorption in water, which is able to initiate plasma with low levels of power density. Once plasma and vapor bubbles are formed, they absorb other wavelengths in addition to the one that initiated it. Other wavelengths, more efficiently generated by diodes or diode pumped lasers, are added into the beam to improve treatment efficiency. This modulated plasma produces fast tissue ablation and good hemostasis effect with minimal overheating of remaining tissue. After plasma and high-energy vapors are generated, only laser radiation that passes through the plasma bubble directly interacts with soft tissues.
    Type: Grant
    Filed: November 9, 2012
    Date of Patent: January 6, 2015
    Assignee: Biolitec Pharma Marketing Ltd
    Inventors: Wolfgang Neuberger, Walter Cecchetti, Leonardo Cecchetti, Filiberto Zattoni
  • Patent number: 8891961
    Abstract: In an optical communication device, a light source is capable of varying the wavelength of light to be output. An optical multiplexer multiplexes light output from the light source with signal light received from a transmission path. To an optical medium, light output from the optical multiplexer is input. A monitor monitors light having a predetermined wavelength output from the optical medium. A wavelength number measuring unit measures the number of wavelengths of signal light transmitted through the transmission path based on the result of monitoring by the monitor.
    Type: Grant
    Filed: December 12, 2012
    Date of Patent: November 18, 2014
    Assignee: Fujitsu Limited
    Inventors: Taizo Maeda, Takashi Toyomaki, Takuya Miyashita
  • Patent number: 8879919
    Abstract: A communications device includes a transmitter device having first and second optical sources and generating respective first and second modulated optical carrier signals at first and second optical carrier frequencies based upon an input signal. The communications device also includes an optical waveguide coupled to the transmitter device, and a receiver device coupled to the optical waveguide and including an FM-PM discriminator having a transfer function with a positive slope portion and a negative slope portion so that the first optical carrier frequency is positioned on the positive slope portion and the second optical carrier frequency is positioned on the negative slope portion.
    Type: Grant
    Filed: September 9, 2011
    Date of Patent: November 4, 2014
    Assignee: Harris Corporation
    Inventors: Robert C. Peach, Charles Middleton, Richard DeSalvo
  • Patent number: 8873970
    Abstract: A method for generating a 400 Gb/s single channel optical signal from multiple modulated subchannels includes carving respective modulated subchannels into return-to-zero RZ modulated subchannels having non-overlapping peaks with intensity modulators having a duty cycle less than 50%, and combining the subchannels into a single channel signal aggregating the bit rate of each of the subchannels. The subchannels are combined with a flat top optical component for increased subsequent receiver sensitivity.
    Type: Grant
    Filed: May 28, 2010
    Date of Patent: October 28, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Jianjun Yu, Dayou Qian, Philip Nan Ji, Ting Wang
  • Patent number: 8818207
    Abstract: A clock signal from a single reference clock is frequency converted, and the frequency-converted signal is input to an equal-interval-optical-frequency-comb generator and a modulator of an optical modulator. By varying the electric frequency of the clock signal input to the equal-interval-optical-frequency-comb generator, frequency intervals of a frequency comb to be generated can be varied, while by selectively employing a particular optical frequency from among the continuous light beams of the generated frequency comb, a frequency comb having unequal intervals can be generated. It is also possible to vary the modulation rate by varying the clock frequency of a driving signal to be input to the optical modulator. By using a clock signal of a single reference clock, the frequency intervals of the frequency comb and the variation of the modulation rate synchronize with each other.
    Type: Grant
    Filed: January 10, 2012
    Date of Patent: August 26, 2014
    Assignee: Fujitsu Limited
    Inventors: Toshiki Tanaka, Tomoo Takahara, Shoichiro Oda, Takeshi Hoshida
  • Patent number: 8818191
    Abstract: A method for reallocating a wavelength in an optical wavelength multiplexer transmission system is disclosed. The method includes switching a supply of a first channel electric signal from a first optical transmitter device to a second optical transmitter device, the first optical transmitter device converting the first channel electric signal into an optical signal of a first wavelength, and the second optical transmitter device converting the first channel electric signal into an optical signal of a second wavelength differing from the first wavelength, and transmitting the optical signal of the second wavelength output from the second optical transmitter device.
    Type: Grant
    Filed: March 30, 2012
    Date of Patent: August 26, 2014
    Assignee: Fujitsu Limited
    Inventors: Takeshi Sakamoto, Ryosuke Goto
  • Patent number: 8805187
    Abstract: An optical waveguide router device with feedback control that uses the fringe frequencies of an optical data signal to derive a wavelength (e.g., temperature) control signal in order to compensate for wavelength variations due to temperature fluctuations and/or other wavelength shifting factors without the need for a reference laser. A monitoring circuit converts an output of at least one output monitoring port to an electrical signal and comparing the output of said at least one output monitoring port against 1) a reference signal, or 2) at least one output from another output monitoring port having a higher or lower frequency fringe of an optical data signal of at least one data port, or 3) at least one output from another output monitoring port having light from diffraction pattern(s), and outputting a control signal reflecting a result of the comparison to control at least one center wavelength of the waveguide router.
    Type: Grant
    Filed: March 19, 2012
    Date of Patent: August 12, 2014
    Assignee: Neophotonics Corporation
    Inventor: Kenneth McGreer
  • Patent number: 8796605
    Abstract: A single-photon receiver and method for detecting a single-photon are presented. The receiver comprises a SPAD that receives a gating signal having a fundamental frequency in the 100 MHz to multiple GHz range. The receiver further comprises a two-stage frequency filter for filtering the output of the SPAD, wherein the filter has: (1) a notch filter response at the fundamental frequency; and (2) a low-pass filter response whose cutoff frequency is less than the first harmonic of the fundamental frequency. As a result, the frequency filter removes substantially all the frequency components in the SPAD output without significant degradation of the signal quality but with reduced complexity, cost, and footprint requirement relative to receivers in the prior art.
    Type: Grant
    Filed: May 4, 2012
    Date of Patent: August 5, 2014
    Assignee: Princeton Lightwave, Inc.
    Inventors: William Paul Mordarski, Mark Allen Itzler
  • Patent number: 8792788
    Abstract: Techniques, devices and systems for optical communications based on wavelength division multiplexing (WDM) that use tunable multi-wavelength laser transmitter modules.
    Type: Grant
    Filed: May 24, 2013
    Date of Patent: July 29, 2014
    Assignee: Google Inc.
    Inventors: Cedric F. Lam, Hong Liu
  • Patent number: 8792792
    Abstract: [PROBLEM] Providing an optical source that outputs optical frequency modulated light having a constant output optical intensity. [MEANS FOR SOLVING THE PROBLEM] Provided is a light source apparatus that outputs an optical signal having an optical frequency corresponding to a frequency control signal, the light source apparatus including a laser light source section that outputs laser light having an optical frequency corresponding to the frequency control signal; and an optical intensity adjusting section that compensates for intensity change of the laser light to output laser light in which the intensity change caused by a change in the optical frequency is restricted.
    Type: Grant
    Filed: October 18, 2011
    Date of Patent: July 29, 2014
    Assignee: Advantest Corporation
    Inventors: Shin Masuda, Kazunori Shiota
  • Patent number: 8781327
    Abstract: An apparatus comprising at least one processor configured to receive a wavelength-division-multiplexed (WDM) signal from a remote node, wherein the WDM signal comprises a first channel carrying a first remotely generated signal, a second channel carrying a second remotely generated signal, and a third channel, adapt the WDM signal into a composite WDM signal by: dropping the first remotely generated signal from the first channel; adding a first locally generated signal to the first channel; and adding a second locally generated signal to the third channel, and provide wavelength locking to the first locally generated signal and the second locally generated signal without providing wavelength locking to the second remotely generated signal.
    Type: Grant
    Filed: July 7, 2011
    Date of Patent: July 15, 2014
    Assignee: Futurewei Technologies, Inc.
    Inventors: Xiao A. Shen, Hongbing Lei, Yu Sheng Bai
  • 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: 8774642
    Abstract: An optical transmission apparatus includes an interleaver configured to filter an optical carrier, a multiplexer configured to combine lights output from the interleaver to generate a composite light, a monitor configured to monitor a light intensity of the composite light, and a control circuit configured to change a grid spacing in a filter characteristic of the interleaver in a direction in which an amount of change in a light intensity of the composite light increases, on the basis of a monitoring result measured while changing a center frequency in the filter characteristic of the interleaver and to change the center frequency in the filter characteristic in a direction in which a maximum value of the light intensity increases, on the basis of the monitoring result.
    Type: Grant
    Filed: May 14, 2012
    Date of Patent: July 8, 2014
    Assignee: Fujitsu Limited
    Inventor: Yasuhiko Aoki
  • Patent number: 8750722
    Abstract: Consistent with the present disclosure, a wavelength division multiplexed (WDM) optical communication system including on-off-keying (OOK) transmitters, for example, may be upgraded to include advanced modulation format transmitters, such as quadrature phase shift keying (QPSK) transmitters. Rather than replace all the OOK transmitters with QPSK transmitters at once, each OOK transmitter is replaced with a lower rate modulation format transmitter, such as a binary phase shift keying (BPSK) transmitter, as capacity needs increase. The BPSK transmitters supply (BPSK) optical signals that are more tolerant of noise caused by cross phase modulation (XPM) induced by OOK signals. Accordingly, such BPSK optical signals have fewer associated data detection errors in the receiver. Moreover, BPSK modulated optical signals induce little XPM-related noise in co-propagating QPSK modulated optical signals.
    Type: Grant
    Filed: December 24, 2010
    Date of Patent: June 10, 2014
    Assignee: Infinera Corporation
    Inventors: Vinayak Dangui, Matthew L. Mitchell
  • Patent number: 8750714
    Abstract: Monolithic single and/or dual detector structures are fabricated on the emitting surface of a VCSEL and/or on a lens or glass substrate configured to be positioned along the axis of emission of an optical light source. Each monolithic detector structure includes one or two PIN detectors fabricated from amorphous silicon germanium with carbon doping or amorphous germanium with hydrogen doping. The monolithic detectors may additionally include various metallization layers, buffer layers, and/or anti-reflective coatings. The monolithic detectors can be grown on 1550 NM VCSELs used in optical transmitters, including lasers with managed chirp and TOSA modules, to reduce power and real estate requirements of the optical transmitters, enabling the optical transmitters to be implemented in long-reach SFP+ transceivers.
    Type: Grant
    Filed: December 9, 2011
    Date of Patent: June 10, 2014
    Assignee: Finisar Corporation
    Inventors: Henry M. Daghighian, Kevin J. McCallion
  • Patent number: 8744265
    Abstract: A passive optical network (PON) component comprising a processor coupled to a plurality of receivers, the processor configured to monitor a plurality of drifting laser wavelengths and cause the drifting laser wavelengths to be tuned to a plurality of pass-bands. Also disclosed is an optical network unit (ONU) comprising a receiver, a transmitter coupled to the receiver, and a partially-tunable laser coupled to the transmitter and having a drifting laser wavelength, wherein the drifting laser wavelength is periodically tuned to one of a plurality of pass-bands. Included is a method comprising monitoring a plurality of drifting laser wavelengths associated with a plurality of pass-bands, and reconfiguring a plurality of time division multiple access (TDMA) timeslots when one of the drifting laser wavelengths migrates from one pass-band to another pass-band.
    Type: Grant
    Filed: April 27, 2007
    Date of Patent: June 3, 2014
    Assignee: Futurewei Technologies, Inc.
    Inventor: Frank J. Effenberger
  • Patent number: 8718476
    Abstract: There is provided a method and apparatus for tuning an optical discriminator to the carrier frequency of an optical signal to allow superior reception of said signal. The carrier frequency of the signal is dithered during a test phase in order to provide information that allows a subsequent tuning phase to optimise the reception of the optical signal, as measured by a signal quality metric. The tuning phase may comprise adjustment of one or both of the carrier frequency and the optical discriminator.
    Type: Grant
    Filed: February 27, 2008
    Date of Patent: May 6, 2014
    Assignee: Xtera Communications, Inc.
    Inventors: Steven Webb, David Winterburn
  • Patent number: 8712252
    Abstract: 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: Grant
    Filed: October 18, 2011
    Date of Patent: April 29, 2014
    Assignee: Advantest Corporation
    Inventors: Shin Masuda, Kazunori Shiota
  • Patent number: 8693867
    Abstract: A system and method for stabilizing a plurality of output frequencies (wavelengths) of a plurality of lasers (106). The laser beams are combined using optical multiplexer (110) and coupled into length-imbalanced (armlength-mismatched) Mach-Zehnder interferometer (MZI) (114) having an optical modulator (e.g. AOM) (122) in one of its arms. The output of the MZI is divided into corresponding beams via optical demultiplexer (128) and each beam is detected by a respective photo-diode (PD) (134). The individual electric signals, so generated, are demodulated using a corresponding plurality of phase-responsive devices (138) and the resulting phase-signals are directed to a plurality of servo-controllers (148) to control the central frequency of the respective lasers (106) via a corresponding plurality of feedback loop circuits (150). The lasers (106) can have different central frequencies which can also be individually tunned using offset modules (141) in the phase-responsive devices (138).
    Type: Grant
    Filed: May 1, 2009
    Date of Patent: April 8, 2014
    Assignee: The Australian National University
    Inventors: Ian C. M. Littler, Jong H. Chow, Malcolm B. Gray, David E. McClelland
  • Patent number: 8687980
    Abstract: A feedback light tuning device and the optical communication system and method using the same are provided. By tuning the feedback light, the mechanism can completely correct the mean-wavelength drift up to 30 nm or 19400 ppm. The mechanism can be applied to various harsh environments which cause the mean-wavelength drift, so as to achieve a required stable mean-wavelength for the light source and to increase the acceptable range of radiation dose.
    Type: Grant
    Filed: July 3, 2012
    Date of Patent: April 1, 2014
    Assignee: National Taiwan University
    Inventors: Tz Shiuan Peng, Lon Wang
  • Patent number: 8676062
    Abstract: In an optical transmission apparatus, a light-emitting laser varies its output wavelength when applied with a wavelength control signal for switching wavelengths. A wavelength controller outputs the wavelength control signal, and a filter unit subjects the wavelength control signal to a filtering process to remove high-frequency noise superimposed on the wavelength control signal. The filter unit stops the filtering process during the wavelength control and executes the filtering process during the operation.
    Type: Grant
    Filed: August 31, 2009
    Date of Patent: March 18, 2014
    Assignee: Fujitsu Limited
    Inventors: Kenichi Nakamoto, Kazuyuki Mori
  • Patent number: 8660437
    Abstract: 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: Grant
    Filed: February 25, 2011
    Date of Patent: February 25, 2014
    Assignee: Emcore Corporation
    Inventor: Henry A. Blauvelt
  • Patent number: 8611750
    Abstract: An apparatus comprising a plurality of optical transmitters coupled to a fiber, a signal generator coupled to the optical transmitters and configured to provide a single pilot tone to the optical transmitters, and a processor positioned within a feedback loop between the fiber and the optical transmitters, the processor configured to adjust a wavelength for each of the optical transmitters to lock the wavelengths. An apparatus comprising at least one processor configured to implement a method comprising receiving an optical signal comprising a pilot tone, detecting an amplitude and a phase of the pilot tone, calculating a quadrature term using the amplitude and the phase, and wavelength locking the optical signal using the quadrature term.
    Type: Grant
    Filed: October 14, 2009
    Date of Patent: December 17, 2013
    Assignee: Futurewei Technologies, Inc.
    Inventors: Hongbing Lei, Xiao A. Shen, Yu Sheng Bai
  • Patent number: 8582984
    Abstract: A waveform controller includes a monitor configured to monitor a waveform of an output pulse obtained by the response of a responsive element to a driving signal supplied thereto and a driving waveform shaper configured to shape a waveform of the driving signal based on a monitoring result obtained by the monitor.
    Type: Grant
    Filed: November 18, 2009
    Date of Patent: November 12, 2013
    Assignee: Fujitsu Limited
    Inventor: Yutaka Kai
  • Patent number: 8571419
    Abstract: In accordance with some embodiments of the present disclosure, a method for spectrally spacing carrier waves comprises determining a frequency offset between a first frequency of a first optical carrier wave and a second frequency of a second optical carrier wave. The method further comprises adjusting the second frequency of the second optical carrier wave according to the frequency offset. The method additionally comprises combining a first optical signal associated with the first carrier wave and a second optical signal associated with he second carrier wave into a multi-frequency signal.
    Type: Grant
    Filed: September 1, 2011
    Date of Patent: October 29, 2013
    Assignee: Fujitsu Limited
    Inventor: Martin Bouda
  • Patent number: 8571420
    Abstract: An apparatus for driving a wavelength-independent light source is provided. The apparatus includes a seed light signal generation unit configured to generate seed light signals with one or more wavelengths based on a wavelength identification signal, a wavelength light detection unit configured to detect the wavelength identification signal from the seed light signals, an extraction unit configured to extract wavelength information corresponding to the detected wavelength identification signal and extract a driving condition of a wavelength-independent light source corresponding to the extracted wavelength information, and a driving unit configured to drive the wavelength-independent light source according to the extracted driving condition.
    Type: Grant
    Filed: December 22, 2011
    Date of Patent: October 29, 2013
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Seung-Hyun Cho, Han-Hyub Lee, Jie-Hyun Lee, Jong-Hoon Lee, Eun-Gu Lee, Eui-Suk Jung, Sang-Soo Lee
  • Patent number: 8565618
    Abstract: An optical transmitter may include a tunable signal source configured to emit a signal to an optical fiber system; a back scatter detector for measuring an amount of back scatter observed following injection of the signal to the optical fiber system; and control logic. The control logic may be configured to cause the tunable signal source to scan through a range of wavelengths. Measured amounts of back scatter are received for each of the wavelengths. A wavelength corresponding to a peak back scatter amount may be identified and the tunable signal source may be set based on the identified wavelength.
    Type: Grant
    Filed: October 5, 2010
    Date of Patent: October 22, 2013
    Assignee: Verizon Patent and Licensing Inc.
    Inventors: Tiejun J. Xia, Glenn A. Wellbrock
  • Patent number: 8565616
    Abstract: A polarized-wave-multiplexing optical transmitter including: an optical combiner generating a polarized-wave-multiplexed optical signal by polarized-wave-multiplexing a first optical modulation signal and a second optical modulation signal; an optical power fluctuation portion fluctuating optical power of the first optical modulation signal and the second optical modulation signal periodically; a total-optical-power detection portion detecting fluctuation amount of total optical power of the polarized-wave-multiplexed optical signal; and an optical power controller reducing an optical power difference between the first optical modulation signal and the second optical modulation signal based on detection result of the total-optical-power detection portion.
    Type: Grant
    Filed: February 16, 2011
    Date of Patent: October 22, 2013
    Assignee: Fujitsu Limited
    Inventors: Toshiki Tanaka, Yuichi Akiyama, Masato Nishihara
  • Patent number: 8559817
    Abstract: A communication system includes a communication unit with a first part and a number of a second part, where the second part is arranged to be placed at the location of an end user, and where the first part is common for a number of second parts. The first part and the second part respectively include a laser, and each second part is connected with the first part by a fiber optic cable and a frequency filter, the first part and the relevant second part being arranged to exchange information by laser light. Each second part includes a tunable laser, the first part is arranged to analyze light received from a second part, and to transmit information to the second part while the first part is receiving light from the second part, and the information contains information for the second part that it should adjust, where required, its frequency or wavelength, and the second part thus is arranged to change its frequency or wavelength.
    Type: Grant
    Filed: October 13, 2009
    Date of Patent: October 15, 2013
    Assignee: Syntune AB
    Inventors: Gert Sarlet, Pierre-Jean Rigole
  • Patent number: 8543004
    Abstract: In one aspect, the present invention embraces a wavelength locking method for causing a narrow-band wavelength spectrum of an optical transmit signal of an optical transceiver device to track a narrow-band wavelength spectrum of an optical receive signal received by the optical transceiver device Further, the present invention embraces a wavelength lockable optical transceiver device, especially for a passive optical transmission network, using this wavelength locking method.
    Type: Grant
    Filed: December 16, 2011
    Date of Patent: September 24, 2013
    Assignee: ADVA Optical Networking SE
    Inventor: Michael Eiselt
  • Patent number: 8515290
    Abstract: The invention relates to a method for coupling a first and second laser (1, 2) having an adjustable difference of their pulse frequencies, which is not equal to zero, wherein the method comprises the following steps: derivation of a first harmonic signal and a signal of the Mth harmonic from the time progression of the light intensity of the pulses emitted by the first laser, mixing of the first harmonic signal and the signal of the Mth harmonic, in order to obtain a first mixed signal, derivation of a second harmonic signal and a signal of the Nth harmonic from the time progression of the light intensity of the pulses emitted by the second laser, mixing of the second harmonic signal and the signal of the Nth harmonic, in order to obtain a second mixed signal, wherein the first and second harmonic signal and the Mth and Nth harmonic are selected in such a manner that the frequencies of the first and second mixed signal are identical, wherein the method furthermore comprises regulation of the pulse frequen
    Type: Grant
    Filed: September 14, 2010
    Date of Patent: August 20, 2013
    Assignee: Giga Optics GmbH
    Inventors: Albrecht Bartels, Raphael Gebs
  • Patent number: 8483565
    Abstract: A data transport card comprising an interface to receive high speed data streams from at least one client, and a pluggable conversion module which converts said data streams into optical data signals and couples these optical data signals into at least one wavelength division multiplexing channel for transport of said optical data signals via an optical fiber.
    Type: Grant
    Filed: August 6, 2010
    Date of Patent: July 9, 2013
    Assignee: ADVA Optical Networking SE
    Inventors: Joerg-Peter Elbers, Klaus Grobe
  • Patent number: 8472805
    Abstract: Techniques, devices and systems for optical communications based on wavelength division multiplexing (WDM) that use tunable multi-wavelength laser transmitter modules.
    Type: Grant
    Filed: May 26, 2010
    Date of Patent: June 25, 2013
    Assignee: Google Inc.
    Inventors: Cedric F. Lam, Hong Liu
  • Patent number: 8463138
    Abstract: Provided is a multi-value optical transmitter in which a DC bias may be controlled to be stabilized so as to obtain stable optical transmission signal quality in multi-value modulation using a dual-electrode MZ modulator. The multi-value optical transmitter includes: D/A converters for performing D/A conversion on first and second modulation data which are set based on an input data series, so as to generate a first and a second multi-value signal, respectively; a dual-electrode MZ modulator including phase modulators for modulating light from a light source based on the first multi-value signal and the second multi-value signal, so as to combine optical signals from the phase modulators to output the optical multi-value signal; an optical output power monitor for detecting average power of the optical multi-value signal; and a DC bias control unit for controlling a DC bias for the dual-electrode MZ modulator, so as to maximize the average power.
    Type: Grant
    Filed: June 29, 2010
    Date of Patent: June 11, 2013
    Assignee: Mitsubishi Electric Corporation
    Inventors: Takashi Sugihara, Soichiro Kametani, Takashi Mizuochi
  • Patent number: 8433200
    Abstract: A quantum key delivery system includes an optical circulator, an optical low-pass filter, optical splitters, and first and second optical couplers arranged for outputting various wavelength components including correlated-photon pair wavelength components outputted from an optical loop path. The first and second optical couplers output light beams, which are sent over first and second quantum channels to first and second recipients, respectively. Other optical splitters are adapted to output light rays, from which first and second control signals are produced. From auxiliary idler light components transmitted over the first and second quantum channels, clock signals are extracted. The system thus extracts a clock signal for detecting arrival of photons, and stably operates with an expected value of the number of generated correlated photon pairs maintained at a substantially constant value.
    Type: Grant
    Filed: August 16, 2011
    Date of Patent: April 30, 2013
    Assignee: Oki Electric Industry Co., Ltd.
    Inventor: Shin Arahira
  • Patent number: 8406637
    Abstract: A system and method are provided for controlling the pre-emphasis applied to an optical signal, in which the output level of individual transmitters is controlled in order to reach a pre-defined desired value of a quality metric. Transmitters are able to adjust their output power without external control in such a way as to optimise the power distribution across the system.
    Type: Grant
    Filed: May 27, 2008
    Date of Patent: March 26, 2013
    Assignee: Xtera Communications, Inc.
    Inventors: Stephen Michael Webb, David Winterburn, Stephen Debruslais