Complementary, Adjusting Stages Patents (Class 359/337.4)
  • Patent number: 11181697
    Abstract: The disclosed apparatus, system and method of the present invention provides improved solutions related to the interconnection of communication cable connectors and communication port receptacles, and more generally, for improved handling and management of communication cable connectors and communication ports. Certain example embodiments suitable for an optical communication application, for example, provide for improved laser safety at the location of an optical communication connector and/or an optical communication port. Moreover, certain example embodiments of the present invention additionally or alternatively otherwise provide for improved communication port, module, device, and/or system handling, administration and/or other management.
    Type: Grant
    Filed: December 31, 2019
    Date of Patent: November 23, 2021
    Assignee: XIEON NETWORKS S.a.r.l.
    Inventors: Carlo Marques, Nuno Ferreira
  • Patent number: 11086074
    Abstract: Methods and techniques are presented to inhibit crystallization in optical waveguide structures, during high temperature annealing or deposition, thus preventing the formation of crystalline grains that scatter and/or absorb light. Dopant atoms or molecules are used to disrupt crystallization. The dopant atoms or molecules are selected to be transparent to the optical signal's wavelength range(s). Optical signals propagating in a waveguide that is fabricated with such techniques will experience reduced propagation loss or insertion loss. The passive dopants can also be used in active devices such as lasers or optical amplifiers that incorporate optically active dopants, as long as the passive dopants are chosen so that they do not interact with the active dopants.
    Type: Grant
    Filed: July 8, 2020
    Date of Patent: August 10, 2021
    Assignee: DICON FIBEROPTICS, INC.
    Inventors: Seng Fatt Liew, Yizhuo He, Ho-Shang Lee
  • Patent number: 10483711
    Abstract: The present disclosure relates to methods and apparatuses for providing optical radiation having improved rise/fall times and improved levels of leakage. One method for amplifying optical radiation includes an intermediate stage (220) having an intermediate active optical fiber (222), the intermediate active optical fiber and a final amplifying stage (230) including a final active optical fiber (232), and providing optical radiation to the input of the intermediate active optical fiber, wherein one or more final optical pump sources (235) are together in a low power state such that the optical radiation is substantially absorbed by the intermediate active optical fiber and such that substantially no optical radiation of the amplified wavelength is transmitted by the intermediate stage. The intermediate active optical fiber (222) can then be switched to a transmissive state by switching the final optical pump source(s) (235) to a high power state.
    Type: Grant
    Filed: March 4, 2016
    Date of Patent: November 19, 2019
    Assignee: Nufern
    Inventor: Peyman Ahmadi
  • Patent number: 10439722
    Abstract: A carrier office includes an optical line terminal, a first transmit-erbium-doped fiber amplifier (EDFA), and a second transmit-EDFA. The OLT is configured to transmit first and second optical signals. The first transmit-EDFA is optically coupled to the OLT and a first feeder fiber, and the first feeder fiber is optically coupled to a first remote node (RN). The first transmit-EDFA is operable between a respective enabled state and a respective disabled state. The second transmit-EDFA is optically coupled to the OLT and a second feeder fiber, and the second feeder fiber is optically coupled to a second RN. The second transmit-EDFA is operable between a respective enabled state and a respective disabled state.
    Type: Grant
    Filed: July 17, 2018
    Date of Patent: October 8, 2019
    Assignee: Google LLC
    Inventors: Liang Du, Yut Loy Chan, Xiangjun Zhao, Changhong Joy Jiang, Cedric Fung Lam, Daoyi Wang, Tao Zhang
  • Patent number: 10050708
    Abstract: A carrier office includes an optical line terminal, a first transmit-erbium-doped fiber amplifier (EDFA), and a second transmit-EDFA. The OLT is configured to transmit first and second optical signals. The first transmit-EDFA is optically coupled to the OLT and a first feeder fiber, and the first feeder fiber is optically coupled to a first remote node (RN). The first transmit-EDFA is operable between a respective enabled state and a respective disabled state. The second transmit-EDFA is optically coupled to the OLT and a second feeder fiber, and the second feeder fiber is optically coupled to a second RN. The second transmit-EDFA is operable between a respective enabled state and a respective disabled state.
    Type: Grant
    Filed: December 20, 2016
    Date of Patent: August 14, 2018
    Assignee: Google LLC
    Inventors: Liang Du, Yut Loy Chan, Xiangjun Zhao, Changhong Joy Jiang, Cedric Fung Lam, Daoyi Wang, Tao Zhang
  • Patent number: 9496676
    Abstract: [Problem] In an optical amplifier, the excitation light level of an excited laser diode decreases, or, when the output of an excitation light is stopped, a backup excited laser diode is operated, and therefore the current consumption increases. [Solution] This optical amplifier is provided with multiple excitation laser diodes, a first current control element, a second current control element, and control means. The excitation laser diodes oscillate excitation light, the excitation light being inputted to an optical fiber amplifier. The first current control element controls a current flowing in the excitation laser diodes. The second current control element controls a current flowing in at least one of the excitation laser diodes. The control means controls the first current control element and the second current control element.
    Type: Grant
    Filed: March 11, 2014
    Date of Patent: November 15, 2016
    Assignee: NEC Corporation
    Inventor: Motoyoshi Kawai
  • Patent number: 9369204
    Abstract: A system for measuring a linewidth of an optical signal includes an optical sensor determining a set of measurements of the linewidth of the optical signal propagated over different distances. Each measurement corresponds to a different distance, and includes a white frequency modulation (FM) noise and a low frequency FM noise. The system also includes a processor for determining values of the white FM noise and the LF FM noise reducing a difference between the measurements and values of the linewidth of the optical signal calculated for the different distances with the values of the white FM noise and the LF FM noise.
    Type: Grant
    Filed: February 27, 2015
    Date of Patent: June 14, 2016
    Assignee: Mitsubishi Electric Research Laboratories, Inc.
    Inventors: Keisuke Kojima, Toshiaki Koike-Akino, Yuichiro Horiguchi
  • Patent number: 9007680
    Abstract: An optical amplifier which amplifies a wavelength division multiplexed optical signal having a variable number of channels associated with different wavelengths and outputs the amplified WDM optical signal. The optical amplifier includes a first optical amplifier which amplifies the wavelength division multiplexed optical signal and outputs the first optical amplifier amplified wavelength division multiplexed optical signal; a variable optical attenuator which controls a level of the first optical amplifier amplified wavelength division multiplexed optical signal and outputs the controlled wavelength division multiplexed optical signal; a second optical amplifier which amplifies the controlled wavelength division multiplexed optical signal and outputs the amplified, controlled wavelength division multiplexed optical signal; and a controller which controls the wavelength division multiplexed optical signal to be amplified with a constant gain.
    Type: Grant
    Filed: September 5, 2013
    Date of Patent: April 14, 2015
    Assignee: Fujitsu Limited
    Inventors: Yasushi Sugaya, Susumu Kinoshita
  • Patent number: 8941911
    Abstract: Doped fiber amplifiers (DFA) using rare-earth doping materials with linear and non-linear interactions between the optical signal to be amplified and the pump laser have become a standard element of optical telecommunications systems for multiple applications including for example extending the reach of optical links before opto-electronic conversion is required or support increased fanout. However, in many applications wherein multiple DFAs are employed the electrical power budget wherein the pump laser diode (LD) represents approximately 25% of the module power consumption directly, and closer to approximately 40-50% once the control and drive electronics for the thermoelectric cooler and LD are included. Accordingly, it would be beneficial to reduce the overall power consumption of a DFA by exploiting unused optical pump power such that multiple gain stages, within the same or different DFAs, may be driven from a single pump LD.
    Type: Grant
    Filed: November 15, 2013
    Date of Patent: January 27, 2015
    Assignee: Viscore Technologies Inc.
    Inventors: Yunqu Liu, Kin-Wai Leong
  • Patent number: 8873135
    Abstract: An extended dynamic range optical amplifier, a method of operation, and a line amplifier configuration include an optical amplifier that can be optimized for high or low span loss conditions by switching an internal stage in or out of an internal light path within the amplifier. The extended dynamic range optical amplifier can include a low gain mode and a high gain mode with an internal switch to switch out a gain mid-stage in a low gain mode to extend the useful dynamic range of the amplifier. Further, the extended dynamic range optical amplifier can use residual pump power from an initial stage to pump the gain mid-stage in the high gain mode. Additionally, the extended dynamic range optical amplifier includes remapping of gain in the initial stage and the gain mid-stage to optimize the amplifier noise performance based on the maximum output power of the amplifier.
    Type: Grant
    Filed: December 21, 2012
    Date of Patent: October 28, 2014
    Assignee: Ciena Corporation
    Inventors: Balakrishnan Sridhar, Jun Bao
  • Patent number: 8854727
    Abstract: An optical amplifier includes: a first amplifier amplifying a signal light by a first excitation light; a variable optical attenuator attenuating the signal light; a second amplifier amplifying the signal light by a second excitation light; a mode selector selecting one of first and second modes; a gain controller, in first mode, controlling first and second excitation lights so that a gain of power of the signal light becomes constant; a first output controller, in second mode, controlling the first excitation light; a second output controller that, in second mode, controlling the second excitation light so that a spontaneous emission light having fixed level is outputted; and an attenuation controller controlling an attenuation of the variable optical attenuator according to an input level of the signal light in first mode, and controlling the attenuation to become a given value larger than a value of first mode in second mode.
    Type: Grant
    Filed: September 30, 2013
    Date of Patent: October 7, 2014
    Assignee: Fujitsu Limited
    Inventors: Tomoaki Takeyama, Kosuke Komaki
  • Patent number: 8824041
    Abstract: The present application discloses a novel chirped pulse amplification (CPA) fiber laser that has easily reconfigured output repetition rate and energy, and high spatial and temporal quality.
    Type: Grant
    Filed: March 14, 2012
    Date of Patent: September 2, 2014
    Assignee: Calmar Optcom, Inc.
    Inventors: Jerry Prawiharjo, Sha Tong, Lawrence West, Jinglun Zhao, Anthony Hong Lin
  • Patent number: 8798464
    Abstract: A method of determining a power correction factor for an optical power of an optical channel of a wavelength division multiplexed communications network. The method comprises configuring an optical source of the communications network to generate an unmodulated optical carrier signal for the optical channel. The method further comprises determining the optical power of the unmodulated optical carrier signal (PHIGH). The method further comprises configuring the optical source to apply a test modulation pattern to the optical carrier signal, to generate a modulated optical carrier signal. The method further comprises determining the optical power of the modulated optical carrier signal (PMOD). The method further comprises determining a power correction factor for the optical channel by determining the difference between the optical powers of the unmodulated optical carrier signal and the modulated optical carrier signal.
    Type: Grant
    Filed: March 19, 2009
    Date of Patent: August 5, 2014
    Assignee: Telefonaktiebolaget L M Ericsson (publ)
    Inventors: Gianmarco Bruno, Riccardo Ceccatelli, Edoardo Mongiardini
  • Patent number: 8730568
    Abstract: Techniques and devices for producing short laser pulses based on chirped pulse amplification.
    Type: Grant
    Filed: September 13, 2010
    Date of Patent: May 20, 2014
    Assignee: Calmar Optcom, Inc.
    Inventors: Sha Tong, Jerry Prawiharjo, Hong Cong, Daniel Beom Soo Soh, Lawrence C. West, Anthony Hong Lin
  • Patent number: 8670176
    Abstract: An optical amplifying device includes a first optical amplifier for amplifying signal light; a second optical amplifier serially connected with the first optical amplifier; an optical device for compensating deterioration of the signal light, the optical device arranged between the first optical amplifier and the second optical amplifier; a variable optical attenuator for attenuating the signal light, the variable optical attenuator arranged between the first optical amplifier and the second optical amplifier; a first automatic level controller for detecting a second amplifier output power and for controlling driving status of the second amplifier in a predetermined output power level; and a first automatic gain controller for detecting an input power of the second optical amplifier and an output power of the second optical amplifier, and for controlling an optical attenuation value of the variable optical attenuator.
    Type: Grant
    Filed: November 5, 2009
    Date of Patent: March 11, 2014
    Assignee: Fujitsu Limited
    Inventors: Mayumi Naito, Yuichi Suzuki, Miki Onaka
  • Patent number: 8547629
    Abstract: An optical amplification device which includes first and second optical amplifiers, and a controller. The first optical amplifier receives a light and amplifies the received light. The second optical amplifier receives the light amplified by the first optical amplifier, and amplifies the received light. When a level of the light received by the first optical amplifier changes by ?, the controller controls a level of the light received by the second optical amplifier to change by approximately ??. In various embodiments, the controller causes the sum of the gains of the first and second optical amplifiers to be constant. In other embodiments, the optical amplification device includes first and second optical amplifier and a gain adjustor. The gain adjustor detects a deviation in gain of the first optical amplifier from a target gain, and adjusts the gain of the second optical amplifier to compensate for the detected deviation.
    Type: Grant
    Filed: March 8, 2011
    Date of Patent: October 1, 2013
    Assignee: Fujitsu Limited
    Inventors: Shinya Inagaki, Norifumi Shukunami, Susumu Kinoshita, Hiroyuki Itou, Taiki Kobayashi
  • Patent number: 8508842
    Abstract: An optical signal amplifier for use in optical networks operating in a ring configuration comprising a first doped optical fiber loop pumped by a first laser and a second optical fiber loop pumped by a second laser.
    Type: Grant
    Filed: April 13, 2007
    Date of Patent: August 13, 2013
    Assignee: Telefonaktiebolaget L M Ericsson (publ)
    Inventor: Rodolfo Di Muro
  • Patent number: 8390923
    Abstract: There is provided an optical amplifier including a pump light source to generate a pump light being capable of changing a wavelength thereof, a first rare earth doped medium to amplify an input signal light by using the pump light generated by the pump light source, a second rare earth doped medium to amplify the input signal light output from the first rare earth doped medium by using a residual pump light that is a portion of the pump light generated by the pump light source, and a wavelength controller to control a wavelength of the pump light generated by the pump light source, based on an input level of the input signal light.
    Type: Grant
    Filed: August 23, 2010
    Date of Patent: March 5, 2013
    Assignee: Fujitsu Limited
    Inventor: Tomoaki Takeyama
  • Patent number: 8379299
    Abstract: An optical amplifier includes a first excitation light source that outputs a first excitation light; a second excitation light source that outputs a second excitation light; a first amplifying optical fiber doped with a rare-earth element and excited by the first excitation light to amplify light input to the first amplifying optical fiber; and a second amplifying optical fiber doped with a rare-earth element and excited by the second excitation light to amplify the light from the first amplifying optical fiber. A ratio between the intensity of the first excitation light and the intensity of the second excitation light is controlled according to the number of signal lights wavelength-multiplexed in the light input.
    Type: Grant
    Filed: January 23, 2010
    Date of Patent: February 19, 2013
    Assignee: Fujitsu Limited
    Inventors: Tomoaki Takeyama, Keiko Sasaki, Shinichirou Muro
  • Patent number: 8363308
    Abstract: A fiber optical device 1A includes an amplification optical fiber 10, a seed light source 15 for supplying pulse seed light to the optical fiber 10, excitation light sources 21 to 25 for supplying excitation light, a bleaching light source 40 for supplying bleaching light for reducing a light transmission loss caused by photodarkening, and a control device 50 that controls the operations of individual portions. The control device 50 divides a period between a first output light pulse and a succeeding second output light pulse into a first period which includes a time point immediately after the output of the first output light pulse and during which the population inversion is unsaturated, and a second period which includes a time point immediately before the output of the second output light pulse, and, to the optical fiber 10, supplies the bleaching light in the first period and supplies the excitation light in the second period.
    Type: Grant
    Filed: August 31, 2009
    Date of Patent: January 29, 2013
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Hitoshi Yamaura, Hiroshi Sekiguchi
  • Publication number: 20130016422
    Abstract: The present invention relates to a Q-switching-induced gain-switched erbium pulse laser system, capable of generating erbium laser pulses within the 2.5 ?m to 3.0 ?m wavelength region, by means of Q-switching operation at 1.6 ?m. At first, an Er3+-doped gain medium is pumped and Q-switched at the wavelength region from 1.58 ?m to 1.62 ?m, so that a Q-switched pulse is formed from the Er3+-doped gain medium. The Q-switched pulse results in an instant positive population inversion between the levels 4I11/2 and 4I13/2 of the Er3+-doped gain medium, followed by a gain-switched laser pulse at the wavelength region from 2.5 ?m to 3.0 ?m.
    Type: Application
    Filed: July 12, 2012
    Publication date: January 17, 2013
    Inventor: Tzong-Yow TSAI
  • Patent number: 8351112
    Abstract: An optical amplifier includes a first amplification medium to receive light obtained by combining signal light input into an input port and the excitation light generated by a light source; a second amplification medium disposed between the first amplification medium and an output port; a loss medium to receive the signal light separated from light output from the first amplification medium; a variable optical attenuator that is disposed on a path that bypasses the loss medium, and to receive the excitation light separated from the light output from the first amplification medium; a first photodetector to detect power of light separated from the signal light transmitted from the second amplification medium; and a controller to control the amount of attenuation for the variable optical attenuator or output power of the light source so that signal light power per wavelength of the signal light becomes closer to a target value.
    Type: Grant
    Filed: January 31, 2011
    Date of Patent: January 8, 2013
    Assignee: Fujitsu Limited
    Inventor: Tomoaki Takeyama
  • Patent number: 8194309
    Abstract: The present invention has an object to provide an optical amplifier capable of realizing a good response characteristic in a wide frequency band, even when a population inversion state is formed by a pumping light supplied to an optical amplification medium and an ASE light generated in the optical amplification medium. To this end, in the optical amplifier according to the present invention, a delayed phase matching fiber in which a first fiber whose response speed is relatively low is arranged on the input side and a second fiber whose response speed is relatively high is arranged on the output side, is used as the optical amplification medium doped with a rare-earth element.
    Type: Grant
    Filed: October 26, 2006
    Date of Patent: June 5, 2012
    Assignee: Fujitsu Limited
    Inventors: Takashi Shimizu, Shinya Inagaki, Tomoaki Takeyama, Keiko Sasaki
  • Patent number: 8189257
    Abstract: A laser structure is provided that includes a pulsed source producing a pulsed signal having a low spontaneous noise component to its spectral output and a pulse-shape that is optimally flat. Also, the laser structure includes one or more optical fiber structures receiving the pulsed signal and performing Raman amplification. The pulsed signal is used to excite in the one or more optical fiber structures possessing normal chromatic dispersion, which acts as a nonlinear system for efficient mid-infrared spectral generation.
    Type: Grant
    Filed: May 1, 2009
    Date of Patent: May 29, 2012
    Assignee: Massachusetts Institute of Technology
    Inventors: Peter T. Rakich, Marin Soljacic, Yoel Fink
  • Patent number: 8174757
    Abstract: A multi-layer optical thin film filter comprising plural deposited optical thin films, wherein optical thin film thickness for each of said optical thin films has a predetermined wavelength spectrum in a predetermined gain equalization band and a predetermined wavelength spectrum in a pumping light transmission band other than said gain equalization band.
    Type: Grant
    Filed: July 26, 2010
    Date of Patent: May 8, 2012
    Assignee: The Furukawa Electric Co., Ltd.
    Inventors: Takahiro Itoh, You Mimura
  • Patent number: 8164826
    Abstract: The present invention provides a multi-stage optical amplifier including a high SN ratio and a method of controlling the same. A multi-stage optical amplifier is configured such that the gain of an amplifying unit in a first stage is greater than that of an amplifying unit in another stage. Therefore, it is possible to increase signal components that have been reduced due to spontaneously emitted light in the first stage, and thus relatively reduce noise. As a result, the obtained signals including a high SN ratio can be maintained in another stage, and it is possible to obtain a high SN ratio.
    Type: Grant
    Filed: March 13, 2008
    Date of Patent: April 24, 2012
    Assignee: NEC Corporation
    Inventor: Takahiro Tomita
  • Patent number: 8111454
    Abstract: Cross-distribution of the output pump power from optical pump units amongst multiple amplifier gain stages even in a single direction of an optical link in an optical communications system. For example, an optical pump unit may output optical pump power that is shared amongst a discrete optical amplification unit and a distributed optical amplification unit (such as a forward and/or backward Raman amplifier). Such sharing has the potential to increase reliability and/or efficiency of the optical communications system.
    Type: Grant
    Filed: February 13, 2009
    Date of Patent: February 7, 2012
    Assignee: Xtera Communications, Inc.
    Inventors: Do-Il Chang, Wayne S. Pelouch
  • Patent number: 8094369
    Abstract: The invention relates to a regulatable optical amplifier which has at least two series-connected amplifier groups, each amplifier group having a regulating device. Connected upstream of the optical amplifier is a power monitor device for detecting changes in the input power, whose electrical output is connected both to the first regulating device and to the second regulating device. In line with the invention, the first and second regulating devices have a control line inserted between them which comprises a series circuit containing a high-pass filter, a delay and signal-shaping unit and a feed-forward control unit for generating a correction signal for the second regulating device. In this arrangement, the high-pass filter has a cut-off frequency which corresponds approximately to the cut-off frequency of the first amplifier group.
    Type: Grant
    Filed: October 25, 2006
    Date of Patent: January 10, 2012
    Assignee: Nokia Siemens Networks GmbH & Co. KG
    Inventor: Kuno Zhuber-Okrog
  • Patent number: 8077383
    Abstract: An optical amplifier including: a first amplifying unit amplifying an input light by utilizing a first excitation light and thereby outputting a first amplified light; a second amplifying unit amplifying the first amplified light by utilizing a second excitation light and thereby outputting a second amplified light; and a control unit detecting a first absorption rate of the first excitation light and a second absorption rate of the second excitation light, and controlling a level of the first excitation light and a level of second excitation light based on the first absorption rate and the second absorption rate. The first absorption rate corresponds to a ratio of the first excitation light absorbed in the first amplifying unit, and the second absorption rate corresponds to a ratio of the second excitation light absorbed in the second amplifying unit.
    Type: Grant
    Filed: March 24, 2008
    Date of Patent: December 13, 2011
    Assignee: Fujitsu Limited
    Inventors: Tomoaki Takeyama, Keiko Sasaki, Shinichirou Muro
  • Patent number: 8045260
    Abstract: The present disclosure relates generally to semiconductor lasers and laser projection systems. According to one embodiment of the present disclosure, a method of operating a laser projection system is provided. According to the method, the laser projection system is utilized to display a sequence of pixelized image frames comprising an alternating sequence of relatively high intensity active projection periods ModON and relatively low intensity inactive projection periods ModOFF. A complementary control signal transitions between an active state QON during the relatively high intensity active projection periods ModON and an inactive state QOFF during the relatively low intensity inactive projection periods ModOFF.
    Type: Grant
    Filed: October 22, 2008
    Date of Patent: October 25, 2011
    Assignee: Corning Incorporated
    Inventors: Vikram Bhatia, Jacques Gollier, Dragan Pikula, Daniel Ohen Ricketts
  • Patent number: 8031396
    Abstract: A modular, compact and widely tunable laser system for the efficient generation of high peak and high average power ultrashort pulses. System compactness is ensured by employing efficient fiber amplifiers, directly or indirectly pumped by diode lasers. Dispersive broadening is introduced by dispersive pulse stretching in the presence of self-phase modulation and gain, resulting in the formation of high-power parabolic pulses. In addition, dispersive broadening is also introduced by simple fiber delay lines or chirped fiber gratings. The phase of the pulses in the dispersive delay line is controlled to quartic order by the use of fibers with varying amounts of waveguide dispersion or by controlling the chirp of the fiber gratings. After amplification, the dispersively stretched pulses can be re-compressed to nearly their bandwidth limit by the implementation of another set of dispersive delay lines.
    Type: Grant
    Filed: October 29, 2009
    Date of Patent: October 4, 2011
    Assignee: Imra America, Inc.
    Inventors: Martin E. Fermann, Almantas Galvanauskas, Donald J. Harter
  • Patent number: 8004752
    Abstract: A multi-wavelength light amplifier includes a first-stage light amplifier which has a first light amplifying optical fiber amplifying a light input, a second stage light amplifier which has a second light amplifying optical fiber amplifying a first light output from the first-stage light amplifier, and an optical system which maintains a second light output of the second-stage light amplifier at a constant power level. The first-stage and second-stage light amplifiers have different gain vs wavelength characteristics so that the multi-wavelength light amplifier has no wavelength-dependence of a gain thereof.
    Type: Grant
    Filed: March 24, 2009
    Date of Patent: August 23, 2011
    Assignee: Fujitsu Limited
    Inventors: Yasushi Sugaya, Miki Takeda, Susumu Kinoshita, Terumi Chikama
  • Patent number: 8004753
    Abstract: A MO-PA type optical amplifier is provided which includes an oscillator and an amplifier including a fiber for optical amplification, including: a reflected-light wavelength conversion fiber which is provided on an optical path between the oscillator and the amplifier and which converts a wavelength of reflected-light traveling toward the oscillator due to Stimulated Raman Scattering; and a filter which is provided on the optical path between the oscillator and the amplifier and which eliminates the wavelength-converted light.
    Type: Grant
    Filed: December 24, 2009
    Date of Patent: August 23, 2011
    Assignee: Fujikura Ltd.
    Inventors: Michihiro Nakai, Tetsuya Sakai
  • Patent number: 7999999
    Abstract: A universal inline functional module for operation with nonzero average gain G?0dB over a bandwidth is provided. The module includes at least one optical functional element producing loss over the bandwidth and at least one rare-earth doped fiber segment. The module produces a flat gain spectrum to within a specified tolerance when made to operate at an average gain of 0 dB over the bandwidth.
    Type: Grant
    Filed: October 29, 2005
    Date of Patent: August 16, 2011
    Assignee: Unopsys, LLC
    Inventors: Paul Francis Wysocki, Mitchell Steven Wlodawski
  • Patent number: 7990608
    Abstract: An optical amplifier reducing gain deviation caused by wavelength arrangement has a first-stage optical amplifying unit, an attenuator, a second-stage optical amplifying unit, an automatic gain controller controlling the first- and second-stage optical amplifying units so that a gain of signal light outputted from the second-stage optical amplifying unit to signal light inputted to the first-stage optical amplifying unit is constant, and an attenuation amount controller controlling an attenuation amount at the attenuator to adjust gain-versus-wavelength characteristic at the automatic-gain-controlled first- and second-stage optical amplifying units on the basis of information on wavelength arrangement and an input level of the signal light inputted to the first-stage optical amplifying unit so that gain slope characteristic at the first- and second-stage optical amplifying units due to the wavelength arrangement and the input level is flattened.
    Type: Grant
    Filed: August 27, 2007
    Date of Patent: August 2, 2011
    Assignee: Fujitsu Limited
    Inventors: Tomoaki Takeyama, Keiko Sasaki, Shinichirou Muro
  • Patent number: 7982945
    Abstract: The present invention relates to an optical amplification module having a construction which effectively suppresses photodarkening, and to a laser light source including the same. The laser light source comprises a light source for outputting light to be amplified, and an optical amplification module. The optical amplification module comprises two types of optical amplification media having different rare earth element concentrations, and a pumping light source. The low concentration medium and the high concentration medium are disposed in the propagation direction of pumping light such that the population inversion of the low concentration medium is higher than that of the high concentration medium.
    Type: Grant
    Filed: April 14, 2009
    Date of Patent: July 19, 2011
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Shinobu Tamaoki, Motoki Kakui
  • Patent number: 7969648
    Abstract: An optical amplification device which includes first and second optical amplifiers, and a controller. The first optical amplifier receives a light and amplifies the received light. The second optical amplifier receives the light amplified by the first optical amplifier, and amplifies the received light. When a level of the light received by the first optical amplifier changes by ?, the controller controls a level of the light received by the second optical amplifier to change by approximately ??. In various embodiments, the controller causes the sum of the gains of the first and second optical amplifiers to be constant. In other embodiments, the optical amplification device includes first and second optical amplifier and a gain adjustor. The gain adjustor detects a deviation in gain of the first optical amplifier from a target gain, and adjusts the gain of the second optical amplifier to compensate for the detected deviation.
    Type: Grant
    Filed: April 19, 2006
    Date of Patent: June 28, 2011
    Assignee: Fujitsu Limited
    Inventors: Shinya Inagaki, Norifumi Shukunami, Susumu Kinoshita, Hiroyuki Itou, Taiki Kobayashi
  • Patent number: 7929201
    Abstract: According to an aspect of the embodiment of the invention, an optical amplifier including an input port, an output port, a plurality of amplifying parts, an optical attenuator, a gain controller and an optical attenuator controller. The plurality of amplifying parts includes an optical amplification medium and a pumping light source for generating pump light. The optical attenuator is optically connected between the amplifying parts. The gain controller controls the pump light power of the pump sources, respectively, in such a way that the ratio decreases in accordance with the gain set value increasing and the ratio interpose between a first threshold level and a second threshold level. The optical attenuator controller controls attenuation of the optical attenuator in order to maintain the sum of generating gains of the amplifying parts in the gain set value in accordance with a state of the signal light inputted into the input port.
    Type: Grant
    Filed: June 20, 2008
    Date of Patent: April 19, 2011
    Assignee: Fujitsu Limited
    Inventors: Tatsuya Tsuzuki, Norifumi Shukunami, Yuji Tamura, Yoshio Shimano, Masao Nakata, Takashi Satou
  • Patent number: 7929202
    Abstract: A semiconductor optical amplifier (SOA) with efficient current injection is described. Injection current density is controlled to be higher in some areas and lower in others to provide, e.g., improved saturation power and/or noise figure. Controlled injection current can be accomplished by varying the resistivity of the current injection electrode. This, in turn, can be accomplished by patterning openings in the dielectric layer above the current injection metallization in a manner which varies the series resistance along the length of the device.
    Type: Grant
    Filed: April 15, 2008
    Date of Patent: April 19, 2011
    Assignee: Thorlabs Quantum Electronics, Inc.
    Inventors: Simarjeet S. Saini, Jerry L. Bowser, Vincent K. Luciani, Peter J. S. Heim, Mario Dagenais, Ryan Enck
  • Patent number: 7924499
    Abstract: An optical amplification device which includes first and second optical amplifiers, and a controller. The first optical amplifier receives a light and amplifies the received light. The second optical amplifier receives the light amplified by the first optical amplifier, and amplifies the received light. When a level of the light received by the first optical amplifier changes by ?, the controller controls a level of the light received by the second optical amplifier to change by approximately ??. In various embodiments, the controller causes the sum of the gains of the first and second optical amplifiers to be constant. In other embodiments, the optical amplification device includes first and second optical amplifier and a gain adjustor. The gain adjustor detects a deviation in gain of the first optical amplifier from a target gain, and adjusts the gain of the second optical amplifier to compensate for the detected deviation.
    Type: Grant
    Filed: June 24, 2010
    Date of Patent: April 12, 2011
    Assignee: Fujitsu Limited
    Inventors: Shinya Inagaki, Norifumi Shukunami, Susumu Kinoshita, Hiroyuki Itou, Taiki Kobayashi
  • Patent number: 7880960
    Abstract: An optical amplifier includes a first optical amplification unit that amplifies input light, a variable optical attenuation unit that attenuates an output of the first optical amplification unit, a second optical amplification unit that amplifies an output of the variable optical attenuation unit, and a loss amount control unit that controls the variable optical attenuation unit, wherein an external attenuating optical medium is inserted between the variable optical attenuation unit and the second optical amplification unit. The optical amplifier includes an abnormality detecting unit that detects abnormality in optical loss based on a light level between the external attenuating optical medium and the second optical amplification unit, and a detection invalidating unit that invalidates any abnormality detected by the abnormality detecting unit when a light level between the variable optical attenuation unit and the external attenuating optical medium is lower than a threshold level.
    Type: Grant
    Filed: June 23, 2009
    Date of Patent: February 1, 2011
    Assignee: Fujitsu Limited
    Inventors: Kosuke Komaki, Yuji Tamura
  • Publication number: 20100315699
    Abstract: Presented is a method and system for phase locking a multi-stage parallel fiber amplifier. The method comprises receiving a signal beam from a first stage, in one path of the multi-stage fiber amplifier, onto a fiber that is pumped to produce a saturated signal beam that is then output to a second stage that outputs an amplified beam. A characteristic of the of the saturated signal beam is that its phase and amplitude do not substantially change based on the amplitude of the signal beam input onto the fiber. The method further detects a portion of the amplified beam to produce a phase indication of the amplified beam relative to amplified beams of the other paths of the multi-stage fiber amplifier. The method modulates the pump level of the first stage to control the phase of amplified beam, and further controls the phases of the other amplified beams of the other paths to phase lock the multi-stage parallel amplifier.
    Type: Application
    Filed: June 15, 2009
    Publication date: December 16, 2010
    Applicant: THE BOEING COMPANY
    Inventors: Shouqin Wang, Metin Mangir
  • Patent number: 7843630
    Abstract: A cascaded optical amplifier including a first optical amplifier and a second optical amplifier in cascaded arrangement is provided. Each of the first optical amplifier and the second optical amplifier has a respective input for receiving an optical signal, an output for outputting an amplified optical signal, and a control input for controlling the gain of the optical amplifier. The cascaded optical amplifier includes a sensor for sensing upstream of the input of the second optical amplier a signal relating to operation of the cascaded optical amplifier. In addition, the cascaded optical amplifier includes a controller for providing control signals to the respective control inputs of the first amplifier and the second amplifier, the controller providing the control signal to the second optical amplifier as a function of the sensed signal.
    Type: Grant
    Filed: January 7, 2008
    Date of Patent: November 30, 2010
    Assignee: Oclaro Technology Limited
    Inventors: André Van Schyndel, Kevan Jones, Selina G. Farwell
  • 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
  • Publication number: 20100128344
    Abstract: A technique for compensating undesired effects in optical links of an optical communication network, using adjustment modules suitable for inserting into optical links, preferably into the links incoming network nodes. Each of the adjustment modules serves for compensating two or more different physical effects accumulated in the optical link when transmitting an optical signal there-along. The module comprises at least two controllable blocks respectively comprising a variable gain optical amplifier VGA for selectively compensating power loss and a tunable dispersion compensation module TDCM for selectively compensating chromatic dispersion.
    Type: Application
    Filed: April 7, 2008
    Publication date: May 27, 2010
    Applicant: ECI TELECOM LTD.
    Inventor: Eyal Lichtman
  • Patent number: 7715092
    Abstract: Raman tilt is induced by the propagation of optical signals in optical communication fibers during and after transient events. Certain characteristics of the light are monitored at each amplification node and Raman tilt correction is achieved by spectral tilt control optics. The light is monitored either as total power, and/or the power of light after passing through one or more optical filters. In the case of EDFA (Erbium Doped Fiber Amplifier) the correction is performed by adjusting stage gains and VOA loss distribution within the amplifier. The light detection is relatively fast, whereby the tilt is compensated by fast controlled VOA and pump power adjustment during a transient event.
    Type: Grant
    Filed: September 28, 2007
    Date of Patent: May 11, 2010
    Assignee: JDS Uniphase Corporation
    Inventors: Maxim Bolshtyansky, Nicholas King
  • Patent number: 7697197
    Abstract: The present invention provides devices and methods for Raman amplification and dispersion compensation. According to one embodiment of the present invention, a dispersion compensating device includes a dispersion compensating fiber having a dispersion more negative than about ?50 ps/nm/km over a wavelength range of about 1555 nm to about 1615 nm; a Raman gain fiber having a dispersion more positive than about ?40 ps/nm/km over a wavelength range of about 1555 nm to about 1615 nm; and a pump source operatively coupled to the dispersion compensating fiber and the Raman gain fiber, the pump source operating at a pump wavelength, wherein the dispersion compensating fiber has a Raman Figure of Merit at the pump wavelength, and wherein the Raman gain fiber has a Raman Figure of Merit at least about equivalent to the Raman Figure of Merit of the dispersion compensating fiber, and wherein the dispersion compensating fiber and the Raman gain fiber are arranged in series between the input and the output of the device.
    Type: Grant
    Filed: July 1, 2008
    Date of Patent: April 13, 2010
    Assignee: Corning Incorporated
    Inventors: Phong Diep, James C. Fajardo
  • Patent number: 7692851
    Abstract: A method for increasing the number of channels amplified by an optical amplifier arrangement is provided. The optical amplifier arrangement includes at least one optical amplifier stage amplifying a first number of channels at a given average gain level. The method begins by selecting a second number of channels to be amplified by the optical amplifier arrangement. At least one additional optical amplifier stage is serially coupled to an input or output of the at least one optical amplifier stage to form a multistage optical amplifier arrangement. The gain shape of the multistage optical amplifier is adjusted to maintain, at the given average gain level or greater, a prescribed degree of gain flatness over an operating bandwidth in which the second number of channels are located.
    Type: Grant
    Filed: October 29, 2005
    Date of Patent: April 6, 2010
    Assignee: UNOPSYS, LLC
    Inventors: Paul Francis Wysocki, Mitchell Steven Wlodawski
  • Patent number: 7692852
    Abstract: A Raman amplifier according to the present invention comprises a plurality of pumping means using semiconductor lasers of Fabry-Perot, DFB, or DBR type or MOPAs, and pumping lights outputted from the pumping means have different central wavelengths, and interval between the adjacent central wavelength is greater than 6 nm and smaller than 35 nm. An optical repeater according to the present invention comprises the above-mentioned Raman amplifier and adapted to compensate loss in an optical fiber transmission line by the Raman amplifier. In a Raman amplification method according to the present invention, the shorter the central wavelength of the pumping light the higher light power of said pumping light.
    Type: Grant
    Filed: March 21, 2007
    Date of Patent: April 6, 2010
    Assignee: The Furukawa Electric Co., Ltd.
    Inventors: Youichi Akasaka, Yoshihiro Emori, Shu Namiki
  • Patent number: 7663801
    Abstract: A method of managing gain tilt in an optical transmission segment including providing an optical transmission segment having a plurality of fiber optic cable spans and a plurality of repeaters coupled to the fiber optic cable spans. Gain tilt in the optical transmission segment is monitored. If negative gain tilt is accumulated at a repeater location in the transmission segment, the repeater at the repeater location is replaced with a higher gain repeater having a higher nominal gain value than the nominal gain value of the repeater being replaced.
    Type: Grant
    Filed: July 31, 2008
    Date of Patent: February 16, 2010
    Assignee: Tyco Telecommunications (US) Inc.
    Inventor: Stuart M. Abbott