Surge Protection Patents (Class 359/341.43)
  • Patent number: 11588295
    Abstract: A system and method for communicating supervisory information between amplifier nodes in an optical communication network utilizes modulation of an included pump source to superimpose the supervisory information on through-transmitted customer signals (or ASE associated with the amplifier if no customer traffic is present). The supervisory information (which may include monitoring messages, provisioning data, protocol updates, and the like) is utilized as an input to an included modulator, which then forms a drive signal for the pump controller. In a preferred embodiment, binary FSK modulation is used.
    Type: Grant
    Filed: November 1, 2019
    Date of Patent: February 21, 2023
    Assignee: II-VI Delaware, Inc.
    Inventors: Aravanan Gurusami, Deepak Devicharan, Timothy K. Zahnley, Martin R. Williams
  • Patent number: 11569907
    Abstract: Systems, methods, and computer-readable media are provided for signaling the presence of a fault in a multi-band optical network or other communication system. In response to a detected fault in a multi-band communication system impacting a specific band of the multi-band communication system, a method, according to one implementation, may include a step of creating a fault signal corresponding to the detected fault. The method may also include the step of conveying the fault signal to at least one of an upstream controller and a downstream controller of the multi-band communication system to trigger an action for handling the fault on the specific band. The action may be handled independently of other actions associated with one or more other bands of the multi-band communication system.
    Type: Grant
    Filed: August 26, 2020
    Date of Patent: January 31, 2023
    Assignee: Ciena Corporation
    Inventors: Edward Chen, Choudhury A. Al Sayeed
  • Patent number: 11546079
    Abstract: An optical end terminal in which protection switching is implemented by using (i) the optical data receiver thereof for detecting a path failure and (ii) the optical data transmitter thereof for signaling the detected path failure to the protection-switching circuit. In an example embodiment, the optical data receiver is configured to detect a path failure based on the presence of certain data-recovery errors. The optical data transmitter is operatively connected to the optical data receiver and configured to generate an in-band dither tone of a predetermined frequency in response to such failure detection. The protection-switching circuit is configured to (i) detect dither tones in the optical signals passing therethrough and (ii) connect the optical data receiver to the protection path instead of the working path in response to detecting the dither tone of the predetermined frequency.
    Type: Grant
    Filed: September 21, 2020
    Date of Patent: January 3, 2023
    Assignee: Nokia Solutions and Networks Oy
    Inventors: Patrick Chilufya Chimfwembe, Andreas Benz, David Samuel Einstein
  • Patent number: 11522629
    Abstract: Systems and methods are provided for amplifying optical signals within one of two optical bands, such as C-band and L-band. An optical amplifying device, according to one implementation, may include a shared optical coil configured to propagate an optical signal. The optical amplifying device may further include a first junction configured to separate the shared optical coil into a first-band optical fiber and a second-band optical coil and a pump device configured to amplify the optical signal in the shared optical coil and the second-band optical coil. The first-band optical fiber may be configured to propagate the optical signal when the optical signal resides in a channel of a first plurality of channels within a first optical band. The second-band optical coil may be configured to propagate the optical signal when the optical signal resides in a channel of a second plurality of channels within a second optical band.
    Type: Grant
    Filed: January 21, 2021
    Date of Patent: December 6, 2022
    Assignee: Ciena Corporation
    Inventors: Jean-Luc Archambault, Rathy Shankar, Damian Flannery
  • Patent number: 11387619
    Abstract: An optical system allows sharing of optical components and seed and pump light to achieve desired optical amplification in laser light while reducing the number of optical components and complexity of the overall optical system and achieving improved performance in lasers and reduced cost in fabrication and final lasers for large scale production of such lasers. Different optical gain sections can be used to allow for sharing of seed and pump light and sharing of optical components while providing multi-stage optical amplification.
    Type: Grant
    Filed: March 6, 2020
    Date of Patent: July 12, 2022
    Assignees: ITF TECHNOLOGIES INC., O-NET COMMUNICATIONS (SHENZHEN) LIMITED
    Inventors: Stéphane Caplette, Hong Xie, Nigel Holehouse, Julien Magné
  • Patent number: 11239628
    Abstract: A method for realizing precise gain control for a hybrid fibre amplifier, and a hybrid fibre amplifier, in which by an erbium-doped fibre amplifier firstly outputting a constant power, a comparable source signal optical power is provided for a raman fibre amplifier of a next stage. A feedback for the gain control may be formed by comparing a source signal optical power calculated after starting pumping of the Raman fibre amplifier and a source signal optical power detected after pumping stops, thereby greatly improving gain control precision of the Raman fibre amplifier. Moreover, the erbium-doped fibre amplifier parts of all the hybrid fibre amplifiers may simultaneously output a constant optical power, and the Raman amplifier parts of all the hybrid fibre amplifiers may simultaneously start calibration, so that the time for starting operation of the entire system may be improved greatly.
    Type: Grant
    Filed: December 19, 2016
    Date of Patent: February 1, 2022
    Inventors: Jintao Tao, Chengpeng Fu, Cuihong Zhang, Fei Cai, Tao Xiong, Yunyu Jing, Qinlian Bu, Chunping Yu
  • Patent number: 10855044
    Abstract: An optical amplifier includes an input port for receiving an input optical signal; a wavelength division multiplexer (204) having a first input coupled to the input port, a second input coupled to a pump source (206), and an output coupled to an amplification fiber (208); and an integrated component (210) configured to provide output monitoring and isolation, wherein the integrated component (210) is configured to separate a first portion of a light signal received from the amplification fiber (208), direct the first portion to a photo detector, direct a second portion of the input light from the amplification fiber (208) to an output port, and attenuate light signals received from the output port.
    Type: Grant
    Filed: September 7, 2015
    Date of Patent: December 1, 2020
    Assignee: Molex, LLC
    Inventors: Fengqing Zhou, Tian Zhu, Haifeng Lv, Yu Hu
  • Patent number: 10476587
    Abstract: One embodiment of the present invention provides an optical link coupling two nodes in an optical transport network. The optical link includes a fiber span, which includes a first optical fiber, a second optical fiber, and a splitter. The input of the splitter is coupled to an input of the fiber span, and first and second outputs of the splitter are coupled, respectively, to the first and second optical fibers. The optical link further includes a first amplifier coupled to the first optical fiber, a second amplifier coupled to the second optical fiber, and an optical switch. Two inputs of the optical switch are coupled to outputs of the first and second amplifiers, respectively; and an output of the optical switch is coupled to an input of a third amplifier.
    Type: Grant
    Filed: May 31, 2016
    Date of Patent: November 12, 2019
    Assignee: Alibaba Group Holding Limited
    Inventor: Chongjin Xie
  • Patent number: 10374704
    Abstract: An optical module includes an optical amplifier configured to amplify Wavelength Division Multiplexing (WDM) channels transmitted on a fiber; and an optical time domain reflectometer (OTDR) configured to transmit an OTDR signal on the fiber and detect a back-scattered signal based thereon to test the fiber, wherein a wavelength of the OTDR signal is one of i) between one or more wavelengths associated with the optical amplifier and one or more wavelengths associated with the WDM channels and ii) greater than the one or more wavelengths associated with the WDM channels, for in-service operation of the OTDR.
    Type: Grant
    Filed: September 15, 2017
    Date of Patent: August 6, 2019
    Assignee: Ciena Corporation
    Inventors: Jean-Luc Archambault, Jun Bao, Balakrishnan Sridhar
  • Patent number: 9755777
    Abstract: An optical transmitter includes a dummy optical source, a polarized wave beam coupler, and an auto gain control (AGC)-system amplifier. The dummy optical source outputs, out of an optical signal in which an optical path signal and an optical packet signal are mixed, a dummy signal having a wavelength identical to that of the optical packet signal. The polarized wave beam coupler multiplexes the dummy signal with the optical signal so that the dummy signal is orthogonal to the optical signal so as to output an output signal. The AGC-system amplifier inputs the output signal, and amplifies the output signal with a predetermined amplification factor corresponding to a power difference between input power and output power of an optical amplifier.
    Type: Grant
    Filed: June 24, 2015
    Date of Patent: September 5, 2017
    Assignee: FUJITSU LIMITED
    Inventors: Koji Bato, Tomoyuki Sakata, Tatsuro Kishida, Koji Matsunaga, Tatsuya Toyozumi, Yuichiro Sakane, Wataru Kawasaki
  • Patent number: 9252558
    Abstract: There is provided an optical amplifier, which includes: an optical amplification medium; a pump light generator configured to generate pump light with a power corresponding to a set control value and supply the generated pump light to the optical amplification medium; a first controller including a level control circuit configured to generate the control value such that an output power of the optical amplification medium approaches a target power, and a limiter configured to limit a range of the control value in variable; and a latch circuit configured to set a specific control value to the pump light generator during a period in which the first controller is in a stop state.
    Type: Grant
    Filed: September 16, 2013
    Date of Patent: February 2, 2016
    Assignee: FUJITSU LIMITED
    Inventor: Masao Nakata
  • Patent number: 8988768
    Abstract: A laser device includes: an optical fiber amplifier that amplifies and emits a signal light; a control unit that controls pumping power for pumping the optical fiber amplifier; and a signal light detector that detects signal light being propagated to the optical fiber amplifier or an ASE photodetector that detects light that is emitted from the optical fiber amplifier and that has wavelength for which the gain is higher than for the signal light, wherein the control unit suppresses the pumping power for pumping the optical fiber amplifier, when the intensity of the signal light detected by the signal light detector becomes less than or equal to a predetermined signal reference value, or when the intensity of the spontaneously emitted light detected by the ASE photodetector becomes greater than or equal to a predetermined ASE reference value.
    Type: Grant
    Filed: January 18, 2012
    Date of Patent: March 24, 2015
    Assignee: Nikon Corporation
    Inventors: Akira Tokuhisa, Naoto Inaba
  • Patent number: 8922880
    Abstract: Embodiments of the present invention disclose a method, an apparatus, and a system for amplifying a burst optical signal. The method includes: monitoring an input status of a signal light; when no signal light is input, controlling output power of a pump light so that a gain medium has output optical power and the output optical power is less than a maximum optical power that the gain medium is capable of outputting when a signal light is input; inputting the pump light into a wavelength division multiplexer so that the wavelength division multiplexer combines the signal light and the pump light and inputs the combined light into the gain medium. With the preceding manners, when no signal light is input, the power of the pump light is controlled.
    Type: Grant
    Filed: June 5, 2012
    Date of Patent: December 30, 2014
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Feng Ding, Hong Liu
  • Patent number: 8922876
    Abstract: An optical amplifying device includes an optical amplification medium configured to be excited by excitation light and amplify signal light, a light loss detector configured to detect a light loss of an optical component optically connected to the optical amplification medium in the amplifying device, and a noise figure deterioration detector configured to detect, based on the light loss detected by the light loss detector, deterioration of a noise figure of the optical amplification medium.
    Type: Grant
    Filed: August 30, 2012
    Date of Patent: December 30, 2014
    Assignee: Fujitsu Limited
    Inventor: Tomoaki Takeyama
  • Patent number: 8922879
    Abstract: An optical amplifying device includes a semiconductor laser that outputs a pump light having a power according to a provided drive current; a rare-earth-doped amplifying medium that amplifies an input light by the pump light output from the semiconductor laser; and a detector that detects, in the power of the pump light, a fluctuation faster than a response speed of a gain of the amplifying medium with respect to the power of the pump light. The optical amplifying device varies the drive current provided to the semiconductor laser based on the fluctuation detected by the detector.
    Type: Grant
    Filed: December 23, 2011
    Date of Patent: December 30, 2014
    Assignee: Fujitsu Limited
    Inventor: Yuji Tamura
  • Patent number: 8908264
    Abstract: A controller for reducing a transient variation of gain of an optical amplifier is disclosed. The controller includes a control circuit adapted to generate an electrical signal mimicking optical gain transient variation upon an abrupt change in input loading conditions. The electrical signal is applied to a variable optical attenuator disposed downstream of the active optical fiber of the optical amplifier. The control circuit can be realized in a variety of ways, but preferably it includes a logarithmic amplifier and a high-pass filter sequentially connected. The logarithmic amplifier is connected to an input tap/photodetector, and the high-pass filter is connected to the variable optical attenuator.
    Type: Grant
    Filed: August 29, 2011
    Date of Patent: December 9, 2014
    Assignee: JDS Uniphase Corporation
    Inventor: Roman Länge
  • Patent number: 8908265
    Abstract: An optical amplifier with improved transient performance has two amplifier stages and a gain flattening filter-inserted between the amplifier stages. A control unit generates a pump control signal for a common pump source pumping both amplifier stages. The pump control signal has a feed-forward component and a feedback component. After a drop of channels the feed-forward control circuit is responsible for the transient performance and fast gain stabilization. The characteristic of the gain flattening filter is taken into account in calculating an optimum feed-forward control signal.
    Type: Grant
    Filed: September 4, 2009
    Date of Patent: December 9, 2014
    Assignee: Xieon Networks S.a.r.l.
    Inventor: Lutz Rapp
  • Patent number: 8699127
    Abstract: An optical amplifier of the present invention includes: an optical amplifier circuit that amplifies input signal light and outputs the amplified light as output signal light; a first monitor for monitoring the presence or absence of the input signal light; and a control circuit that, when receiving a shutdown control signal, controls the optical amplifier circuit such that a shutdown control speed for reducing a level of the output signal light to zero differs according to the presence or absence of the input signal light.
    Type: Grant
    Filed: April 13, 2011
    Date of Patent: April 15, 2014
    Assignee: NEC Corporation
    Inventor: Katsuyuki Mino
  • Patent number: 8576480
    Abstract: An optical amplifier using the evanescent light to control the optical output level is provided. The optical amplifier includes: a waveguide path transmitting an optical signal; an optical amplification unit formed on the waveguide path and amplifying the optical signal by an excitation light; an irradiation unit irradiating the excitation light to the optical amplification unit; an optical detection unit generating an electric signal which corresponds to a detected light; a branching unit branching an evanescent light being the optical signal outputted from the optical amplification unit and leaked outside the waveguide path, and focusing the evanescent light on the optical detection unit; a wavelength detection unit detecting a wavelength multiplicity of the optical signal based on the detected evanescent light; and a light amount adjustment unit adjusting a light amount of the excitation light irradiated by the irradiation unit based on the wavelength multiplicity.
    Type: Grant
    Filed: June 7, 2012
    Date of Patent: November 5, 2013
    Assignee: NEC Corporation
    Inventor: Hideshi Yoshida
  • Patent number: 8493653
    Abstract: The present invention relates to an optical fiber amplifying module equipped with a structure for stably attaining a high gain even when amplifying light having a low duty cycle. The optical fiber amplifying module comprises at least three amplification optical fibers successively arranged from an input connector to an output collimator. A bandpass filter is arranged between the first- and second-stage amplification optical fibers. Control means having a structure constituted by optically passive components alone or a feedback structure functions so as to render an upper limit to a gain for input light in the first-stage amplification optical fiber, thereby preventing the deterioration in performances such as destruction of the bandpass filter from occurring in optical components positioned on the upstream side of the final-stage amplification optical fiber.
    Type: Grant
    Filed: November 17, 2011
    Date of Patent: July 23, 2013
    Assignee: Megaopto Co., Ltd.
    Inventor: Motoki Kakui
  • Patent number: 8427739
    Abstract: An optical amplifier includes an input port, an output port, an amplification medium, a light source, a monitor, and a controller. The amplification medium with which doped an rare-earth element for optical amplification is allocated on an optical path between the input port and the output port. The light source supplies the amplification medium with an excitation light. The monitor monitors a total power of an optical signal of each wavelength according to a monitor period which is longer than a transient response time of the amplification medium. The controller controls the light source so that a power of the excitation light is constant when a monitor value of the monitor is equal to or smaller than a predetermined threshold value and controls the light source so that an optical gain in the amplification medium is constant when the monitor value is larger than the predetermined threshold value.
    Type: Grant
    Filed: April 18, 2011
    Date of Patent: April 23, 2013
    Assignee: Fujitsu Limited
    Inventors: Kyosuke Sone, Susumu Kinoshita
  • Patent number: 8259390
    Abstract: An optical amplifier apparatus includes an optical amplifier including an amplification medium doped with an active substance, the amplification medium excited in order to amplify light; a semiconductor optical amplifier arranged after the optical amplifier; a driver for supplying a driving current with respect to the semiconductor optical amplifier in order that the semiconductor optical amplifier has an amplification characteristic with respect to an input light, the amplification characteristic including a gain non-saturated region and a gain saturated region; and an input-light level adjuster for adjusting an out put light of the optical amplifier to the input light level of the semiconductor optical amplifier, the input light level being set up between the gain non-saturated region and the gain saturated region.
    Type: Grant
    Filed: March 23, 2009
    Date of Patent: September 4, 2012
    Assignee: Fujitsu Limited
    Inventors: Ryuta Hoshi, Toshihiro Ohtani
  • Patent number: 8174759
    Abstract: The invention relates to an apparatus for dynamically controlling the gain of an optically pumped optical amplifier, and the optical amplifier including such apparatus, which utilizes a multiplying digital to analog converter to implement a digitally adjustable analog feed forward control of a source of pump radiation of the optical amplifier.
    Type: Grant
    Filed: June 19, 2009
    Date of Patent: May 8, 2012
    Inventors: Srikanth Ramakrishnan, Dusan Ivancevic
  • Patent number: 8134775
    Abstract: An optical amplifier includes a light source that outputs light having an intensity corresponding to a supplied driving power; a modulator that modulates the light output from the light source in response to an input modulation signal; a Raman amplifier that performs Raman amplification on the light modulated by the modulator using a highly-nonlinear medium; and a driver that supplies the driving power to drive the light source and inputs the modulation signal to the modulator. The driver starts inputting the modulation signal to the modulation unit before the intensity of the light propagating through the Raman amplifier exceeds an intensity value at which stimulated Brillouin scattering occurs in the Raman amplifier.
    Type: Grant
    Filed: March 11, 2009
    Date of Patent: March 13, 2012
    Assignee: Fujitsu Limited
    Inventors: Yuichi Suzuki, Norifumi Shukunami
  • Patent number: 8098424
    Abstract: The present invention relates to an optical fiber amplifying module equipped with a structure for stably attaining a high gain even when amplifying light having a low duty cycle. The optical fiber amplifying module comprises at least three amplification optical fibers successively arranged from an input connector to an output collimator. A bandpass filter is arranged between the first- and second-stage amplification optical fibers. Control means having a structure constituted by optically passive components alone or a feedback structure functions so as to render an upper limit to a gain for input light in the first-stage amplification optical fiber, thereby preventing the deterioration in performances such as destruction of the bandpass filter from occurring in optical components positioned on the upstream side of the final-stage amplification optical fiber.
    Type: Grant
    Filed: March 30, 2007
    Date of Patent: January 17, 2012
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Motoki Kakui
  • Patent number: 7995269
    Abstract: A method for cost-effective optical transmission with fast Raman tilt or other transient event control uses a combination of Erbium-doped fiber amplifiers (EDFAs) and Raman fiber amplifiers (RFAs), where EDFAs are used as the primary optical amplifiers to compensate the span loss while the RFA (advantageously a forward-pumped RFA) is used only in some specific spans with a feed-forward control circuit serving as a fast Raman tilt transient compensator, the RFA also serving as an optical amplifier. A long haul optical transmission system using feed-forward controlled RFA's periodically spaced along its length, for example, when add-drop multiplexing is used, makes full use of the economics of EDFAs and the fast tilt transient control capability of a RFA enabled by an adjustable speed feed-forward or feed-back control technique.
    Type: Grant
    Filed: November 4, 2008
    Date of Patent: August 9, 2011
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Xiang Zhou, Martin Birk
  • Patent number: 7961380
    Abstract: The specification describes an improved approach to suppressing fast transients in optical amplifier systems. The approach relies on operating the amplifier in an automatic power-mode control with an extra loss component. It is applicable to optical amplifiers based on rare earth amplifier media, such as erbium doped fiber amplifiers (EDFAs).
    Type: Grant
    Filed: February 19, 2008
    Date of Patent: June 14, 2011
    Assignee: Oclaro North America
    Inventors: Brian Shia, Douglas Llewellyn Butler, Martin Williams
  • Patent number: 7876498
    Abstract: In some embodiments, the present invention provides an apparatus and process wherein excess stored optical energy is removed from one or more stages in a fiber-amplifier, in order to stabilize the gain and obtain a constant level of energy per pulse. In some embodiments, a method of the invention includes providing a gain fiber, optically pumping the gain fiber using pump light, amplifying seed-signal pulses having a signal wavelength using the gain fiber to obtain amplified output pulses, and automatically limiting a gain of the gain fiber. In some embodiments, an apparatus of the invention includes a gain fiber, a source of pump light coupled to the gain fiber, a source of seed-signal pulses having a signal wavelength coupled to the gain fiber, wherein the gain fiber outputs amplified signal pulses, and an automatic-gain-control mechanism configured to limit gain of the gain fiber.
    Type: Grant
    Filed: March 24, 2008
    Date of Patent: January 25, 2011
    Assignee: Lockheed Martin Corporation
    Inventors: Eric C. Honea, Roy D. Mead, John D. Minelly
  • Patent number: 7844185
    Abstract: Apparatuses and methods are provided which suppress a surge component occurring at an optical amplifier on an optical path through which an optical burst signal is transmitted. An optical amplifier may experience a surge due to the power variation of the optical burst signal that is fed to the optical amplifier. To suppress such a surge component, a power corresponding to a number of wavelengths of an optical burst signal to be input is calculated. The optical amplifier is instructed to generate an optical signal with a power corresponding to a difference between a set value and the calculated power. The generated optical signal and the optical burst signal to be input are coupled and output according to the instruction. Thus, the optical amplifier can receive the optical signal with the constant power and the surge component at the optical amplifier can be suppressed.
    Type: Grant
    Filed: November 2, 2005
    Date of Patent: November 30, 2010
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Keun-joo Park, Hyun-chin Kim, June-koo Rhee, Young-kwang Seo, Chun-ju Youn
  • Publication number: 20100245989
    Abstract: A control circuit for a fiber amplifier having a first stage pump and at least one second stage pump and method of controlling thereof is disclosed. The control circuit includes a control gate controlling a current through the first stage pump. A sensor for detecting a voltage across the first stage pump and providing a measured output of the voltage is provided. The control circuit further includes a control loop configured for selectively controlling the current through the control gate in accordance with the measured output and a set reference point is also provided.
    Type: Application
    Filed: March 31, 2009
    Publication date: September 30, 2010
    Applicant: IPG Photonics Corporation
    Inventor: Phil Simmons
  • Patent number: 7751119
    Abstract: According to an optical surge suppressive type optical amplifier in the present invention, for a WDM optical amplifier having a multi-stages amplification configuration in which a plurality of optical amplifying means is connected in series, an optical amplifying medium capable of causing a homogeneous up-conversion (HUC) phenomenon is applied to the optical amplifying means on the signal light output side, so that an optical surge is suppressed utilizing the degradation of gain efficiency by the HUC caused at the time when the input power is decreased. Further, for a one wave optical amplifier, an optical amplifying medium capable of causing a pair induced quenching (PIQ) phenomenon is applied to the optical amplifying means on the signal light input side, so that the optical surge is suppressed utilizing the degradation of output power efficiency by the PIQ caused at the time when the input power is increased.
    Type: Grant
    Filed: August 25, 2008
    Date of Patent: July 6, 2010
    Assignee: Fujitsu Limited
    Inventors: Miki Onaka, Etsuko Hayashi
  • Patent number: 7746549
    Abstract: An optical communication apparatus includes an erbium-doped optical fiber amplifier for amplifying a modulated optical signal, wherein a light which is not modulated is inputted to the erbium-doped optical fiber amplifier together with the optical signal.
    Type: Grant
    Filed: October 30, 2006
    Date of Patent: June 29, 2010
    Assignee: Yokogawa Electric Corporation
    Inventors: Naoaki Machida, Shinji Iio, Morio Wada, Daisuke Hayashi, Shinji Kobayashi, Masayuki Suehiro, Katsuya Ikezawa, Akira Miura, Sadaharu Oka, Chie Sato, Mamoru Hihara, Tsuyoshi Yakihara, Shinichi Nakajima
  • Patent number: 7636192
    Abstract: A method for cost-effective optical transmission with fast Raman tilt or other transient event control uses a combination of Erbium-doped fiber amplifiers (EDFAs) and Raman fiber amplifiers (RFAs), where EDFAs are used as the primary optical amplifiers to compensate the span loss while the RFA (advantageously a forward-pumped RFA) is used only in some specific spans with a feed-forward control circuit serving as a fast Raman tilt transient compensator, the RFA also serving as an optical amplifier. A long haul optical transmission system using feed-forward controlled RFA's periodically spaced along its length, for example, when add-drop multiplexing is used, makes full use of the economics of EDFAs and the fast tilt transient control capability of a RFA enabled by an adjustable speed feed-forward or feed-back control technique.
    Type: Grant
    Filed: June 15, 2006
    Date of Patent: December 22, 2009
    Assignee: AT&T Corp.
    Inventors: Xiang Zhou, Martin Birk
  • Patent number: 7535632
    Abstract: There is described a method for compensation of gain variations in a multistage optical amplifier, for the amplification of an optical wavelength multiplex signal, comprising several amplifier stages in series, each with at least one pumping device. Gain variation occurring after a switching process can easily be compensated for, when the power jump expected at the second amplifier stage is determined and, depending thereon, a new pump power is calculated for the corresponding pump device, the new pump power is set for the pump device before the power jump arrives at the input of the second stage.
    Type: Grant
    Filed: May 1, 2007
    Date of Patent: May 19, 2009
    Assignee: Nokia Siemens Networks GmbH & Co KG
    Inventor: Lutz Rapp
  • Patent number: 7453627
    Abstract: The present disclosure relates to a method for regulating a pump power of an optical amplifier, where a multiplexed broadband optical signal having several channels is amplified at a certain gain value while a change in power is detected at the input or output of the amplifier. A new pump power is calculated and adjusted based on a previously provided stable gain state of the optical amplifier after detecting the change in power such that deviations of the gain value remain minimal as planned temporary interface transients during a specific interval. The new pump power is thus calculated very accurately and quickly according to a model that takes into account the actual gain value, the wavelength dependence of active channels, aging effects, and non-linear amplification effects.
    Type: Grant
    Filed: December 15, 2004
    Date of Patent: November 18, 2008
    Assignee: Siemens Aktiengesellschaft
    Inventor: Lutz Rapp
  • Patent number: 7446932
    Abstract: A method for cost-effective optical transmission with fast Raman tilt or other transient event control uses a combination of Erbium-doped fiber amplifiers (EDFAs) and Raman fiber amplifiers (RFAs), where EDFAs are used as the primary optical amplifiers to compensate the span loss while the RFA (advantageously a forward-pumped RFA) is used only in some specific spans with a feed-forward control circuit serving as a fast Raman tilt transient compensator, the RFA also serving as an optical amplifier. A long haul optical transmission system using feed-forward controlled RFA's periodically spaced along its length, for example, when add-drop multiplexing is used, makes full use of the economics of EDFAs and the fast tilt transient control capability of a RFA enabled by an adjustable speed feed-forward or feed-back control technique.
    Type: Grant
    Filed: June 15, 2006
    Date of Patent: November 4, 2008
    Assignee: AT&T Corporation
    Inventors: Xiang Zhou, Martin Birk
  • Patent number: 7417792
    Abstract: An optical amplification device is disclosed that performs feedback control to maintain an amplification gain to be a constant based on measured power of input light and power of output light. The device includes a feedback control coefficient switching unit configured to, when performing the feedback control on a difference from an object amplification gain, distinguish a state of increasing or decreasing the number of frequencies of the input light and a steady state by making comparison and determination whether an amplitude of at least one of the power of the input light and the power of the output light is in a predetermined range, and switch the feedback control coefficient. Therefore, it is possible to reduce variation of the power of the output light caused by noise in the steady state without affecting operations of increasing and decreasing a number of frequencies of a light signal.
    Type: Grant
    Filed: March 15, 2005
    Date of Patent: August 26, 2008
    Assignee: Fujitsu Limited
    Inventors: Kazuhiko Hatae, Nobukazu Koizumi, Masato Oota
  • Patent number: 7177074
    Abstract: A circuit and associated method for safety shutdown of an optical amplifier, wherein the power of an amplified spontaneous emission ASE is subject to a correction factor and subtracted from a measured signal extracted from the optical signal.
    Type: Grant
    Filed: September 18, 2002
    Date of Patent: February 13, 2007
    Assignee: Siemens Aktiengesellschaft
    Inventor: Lutz Rapp
  • Patent number: 7164527
    Abstract: A method, apparatus and system for controlling power transients in amplified optical transmission system includes, in response to the detection of a power transient in an optical signal, varying a gain of at least one amplifier to correct for a time delay in a gain response associated with a gain change in an amplifier. Alternatively, the method, apparatus and system further include in response to the detection of the power transient, adjusting the gain of at least one amplifier to correct for a change in signal power.
    Type: Grant
    Filed: April 9, 2003
    Date of Patent: January 16, 2007
    Assignee: Lucent Technologies Inc.
    Inventors: Nathan Myron Denkin, Gerard Lingner, III
  • Patent number: 7034996
    Abstract: An optical transmitter 11 outputs an optical signal, and an optical booster amplifier 12 amplifies the optical signal and sends the amplified optical signal to an optical fiber 101 forming an optical transmission line. When detecting an optical signal fluctuation factor, an optical transmitter control part 13 outputs a light surge warning signal 111 prior to an optical signal fluctuation, and a gain control part 14 responds to the light surge warning signal 111 to decrease the gain of the optical booster amplifier 12 down to a level where no light surge occurs.
    Type: Grant
    Filed: June 1, 2004
    Date of Patent: April 25, 2006
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Shigeo Yamanaka
  • Patent number: 6985284
    Abstract: A method, apparatus and system for controlling power transients in a Raman-amplified optical transmission system includes, in response to the detection of a power transient in an optical signal, varying the gain of at least one dispersion compensating module (DCM) in the Raman-amplified optical transmission system to correct for a change in signal power caused by the power transient.
    Type: Grant
    Filed: November 12, 2002
    Date of Patent: January 10, 2006
    Assignee: Lucent Technologies Inc.
    Inventors: Nathan Myron Denkin, Gerard Lingner, III
  • Patent number: 6894832
    Abstract: A technique for adaptively controlling a gain of an optical amplifier is disclosed. In one particular exemplary embodiment, the technique may be realized by a method comprising the steps of measuring an output power signal of the optical amplifier; computing a command signal from an input power signal; computing a model state signal of a reference model; computing a model output signal of the reference model based at least in part on the model state signal; computing an error signal between the model output signal and the output power signal of the optical amplifier; adjusting at least one adaptive control gain value to minimize the error signal; and computing a control input signal for driving the optical amplifier based at least in part on the at least one adaptive control gain value, the error signal, the model state signal and the command signal.
    Type: Grant
    Filed: August 30, 2002
    Date of Patent: May 17, 2005
    Assignee: Nortel Networks Limited
    Inventors: James Aweya, Delfin Y. Montuno, Michel Ouellette, Kent Felske
  • Patent number: 6847478
    Abstract: An object of the invention is to provide an optical amplification apparatus using Raman amplification, which can reliably judge an input interruption of signal light and can shut down the supply of excitation light in accordance with a judged input interruption of the signal light. To this end, the optical amplification apparatus of the present invention comprises an input interruption detection means for detecting a noise light component due to the Raman amplification, and judging an input interruption of the signal light based on the detection result, and further comprises a shut down control means for shutting down supply of the excitation light when an input interruption of the signal light is judged by the input interruption detection means.
    Type: Grant
    Filed: December 15, 2003
    Date of Patent: January 25, 2005
    Assignee: Fujitsu Limited
    Inventors: Tomoto Tanaka, Miki Onaka, Etsuko Hayashi, Yasushi Sugaya
  • Publication number: 20040218258
    Abstract: A method and apparatus for controlling transients in an optical signal propagating along an optical fiber path interconnecting a plurality of network elements employs a power threshold to determine an appropriate response given a change in optical signal power.
    Type: Application
    Filed: May 26, 2004
    Publication date: November 4, 2004
    Inventors: Robert D. Feldman, Mahan Movassaghi, David A. Sadler, William A. Thompson
  • Publication number: 20040201882
    Abstract: An object of the present invention is to prevent an interruption circuit of an optical amplifier from malfunctioning due to Raman pump wave. A typical mode of the present invention is characterized in that an pump wave elimination filter is inserted before an input-light detector and a reflected-light detector which constitute the optical amplifier. This permits only a signal component to be detected, enabling interruption operation, while eliminating a remaining component of Raman pump wave transmitted from for example a downstream of an optical fiber transmission line. In addition, a judgment threshold value for the interruption operation is changed according to ON/OFF condition of the pump wave. Or the Raman pump wave itself is used for detecting output's open.
    Type: Application
    Filed: March 2, 2001
    Publication date: October 14, 2004
    Inventor: Nobuhiko Kikuchi
  • Patent number: 6762878
    Abstract: This invention provides a gain control device and method for an erbium doped fiber amplifier that is capable of maintaining a constant gain irrespective of the intensity variation of the input signal light.
    Type: Grant
    Filed: September 6, 2001
    Date of Patent: July 13, 2004
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Tae-Sung Park, Do-In Choi, Yun-Je Oh
  • Patent number: 6757099
    Abstract: An improved optical power transient control scheme is provided for optical amplifiers used in long haul, high capacity DWDM optical networks. The optical power transient control scheme employs a combination of feed-forward and feedback control mechanisms to adjust the pump laser current of an amplifier. In this way, the optical power transient control scheme allows for very fast detection of transient changes in optical input power and fast control settling time with minimal optical power degradation.
    Type: Grant
    Filed: August 15, 2001
    Date of Patent: June 29, 2004
    Assignee: PTS Corporation
    Inventors: Lacra Pavel, Xiaona Meng
  • Patent number: 6738184
    Abstract: Optical signals (multi-wavelength light) are guided to an EDF. The EDF is supplied with pump light generated by a first and a second pump light sources. Dummy light is generated by a dummy light source and supplied to the EDF. The wavelength of the dummy light is shorter than a wavelength range in which the optical signals are allocated.
    Type: Grant
    Filed: September 12, 2001
    Date of Patent: May 18, 2004
    Assignee: Fujitsu Limited
    Inventors: Etsuko Hayashi, Yasushi Sugaya, Yoshihito Onoda, Keiko Sasaki
  • Publication number: 20040091205
    Abstract: A method, apparatus and system for controlling power transients in a Raman-amplified optical transmission system includes, in response to the detection of a power transient in an optical signal, varying the gain of at least one dispersion compensating module (DCM) in the Raman-amplified optical transmission system to correct for a change in signal power caused by the power transient.
    Type: Application
    Filed: November 12, 2002
    Publication date: May 13, 2004
    Applicant: LUCENT TECHNOLOGIES INC.
    Inventors: Nathan Myron Denkin, Gerard Lingner
  • Patent number: RE40270
    Abstract: An optical brancher branches an input optical signal into two. An optical detector converts one optical signal branched by the optical brancher into an electrical signal. A first controller generates a control electrical signal having a waveform obtained by inverting the envelope of the electrical signal. Based on the control electrical signal, an optical signal generator produces a dummy optical signal having a waveform ?d and an amplitude ?/2. The other signal branched by the optical brancher is delayed by a delay unit for a predetermined time, and then multiplexed by an optical multiplexer with the dummy optical signal from the optical signal generator. An optical amplifier amplifies amultiplexed optical signal. An optical filter separates an optical signal of a wavelength ?1 from the amplified optical signal. Thus, optical signal amplification can be carried out without optical surges.
    Type: Grant
    Filed: December 17, 2004
    Date of Patent: April 29, 2008
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Toru Shiozaki, Masaru Fuse