With Multiple Systems Patents (Class 359/341.33)
  • Patent number: 7729046
    Abstract: In a laser device, a crystal array includes a laser gain crystal and an optically non-linear frequency conversion crystal. A pump source couples at least two mutually spatially separated pump beams into the crystal array. Between two pump beams, a saw kerf of the crystal array extends parallel to the pump beams.
    Type: Grant
    Filed: July 9, 2008
    Date of Patent: June 1, 2010
    Assignee: Osram Opto Semiconductors GmbH
    Inventors: Michael Kühnelt, Thomas Schwarz, Ulrich Steegmüller, Frank Singer
  • Publication number: 20100067099
    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: Application
    Filed: November 16, 2009
    Publication date: March 18, 2010
    Applicant: The Furukawa Electric Co., Ltd.
    Inventors: Youichi AKASAKA, Yoshihiro Emori, Shu Namiki
  • Publication number: 20090279166
    Abstract: There is provided a long-band rare-earth-doped optical amplifier and method for amplifying an optical signal. The optical amplifier has a pre-, a mid- and a post-amplification stage. Only the mid-amplification stage is pumped with a pump light source. The other two are pumped using Amplified Spontaneous Emission (ASE) generated in the mid-amplification stage. An optical coupling device is used to couple the three amplification stages together and to split the ASE generated in the mid-amplification stage and available at one end of the mid-amplification stage. One part of the split ASE is used to pump the pre-amplification stage while the other part is used to pump the post-amplification stage.
    Type: Application
    Filed: May 9, 2008
    Publication date: November 12, 2009
    Inventor: Louis DESBIENS
  • Publication number: 20090201576
    Abstract: A fiber amplifier having two erbium doped fiber coils and a pump laser diode optically coupled, through a fiber array, to a planar lightwave circuit, is described. A photodetector array, a multiport free-space optical isolator, and a strip of thin-film gain flattening filter are attached to a side surface of the planar lightwave circuit, which has a tunable optical power splitter for variably splitting the optical pump power for the laser diode between the two erbium doped fiber coils, and variable tilters for correcting the gain tilt of the amplifier. The variable splitter and the tilters are thermally tunable Mach-Zehnder interferometers.
    Type: Application
    Filed: February 12, 2009
    Publication date: August 13, 2009
    Inventors: Maxim BOLSHTYANSKY, Gregory Cowle, Barrie Keyworth, Peter David Roorda
  • Patent number: 7515331
    Abstract: An apparatus for amplifying optical communications systems is provided in which one or more amplifier modules, each containing an optical amplifier and at least two pump lasers, are optically isolated from a plurality of control modules. Each control module controls a single pump laser in one or more of the amplifier modules. A control module can thus be removed without disabling any amplifier module, while the plurality of pump lasers in each amplifier module allow for effective operation even if one of the pump lasers should fail. The pump lasers in each module are controlled by a master-slave relationship, whereby the master pump laser is adjusted to optimise overall output, while the slave laser(s) are adjusted to equalize the power output of the lasers.
    Type: Grant
    Filed: July 24, 2006
    Date of Patent: April 7, 2009
    Assignee: Xtera Communications Ltd.
    Inventor: Alan Olway
  • Patent number: 7508575
    Abstract: A method for pumping remote optically-pumped fiber amplifiers (ROPAs) in fiber-optic telecommunication systems is disclosed which uses cascaded Raman amplification to increase the maximum amount of pump power that can be delivered to the ROPA. According to the prior art, high power at the ROPA pump wavelength, ?p, is launched directly into the fiber and the maximum launch power is limited by the onset of pump depletion by Raman noise and oscillations due to the high Raman gain at ˜(?p+100) nm. In preferred embodiments of the present invention, a ‘primary’ pump source of wavelength shorter than ?p is launched into the delivery fiber along with two or more significantly lower-power ‘seed’ sources, among which is included one at ?p. The wavelength and power of the seed source(s) are chosen such that, when combined with the high-power primary source, a series, n, where n?2, of Raman conversions within the fiber ultimately leads to the development of high power at ?p.
    Type: Grant
    Filed: September 28, 2004
    Date of Patent: March 24, 2009
    Assignee: MPB
    Inventors: Serguei Papernyi, Vladimir Karpov, Vladimir Ivanov, Wallace Clements
  • Patent number: 7346280
    Abstract: A bi-directional configuration is employed to implement a hybrid ultra long haul (ULH)/long haul (LH) optical transmission system. The link carries ULH channels and LH channels in opposite directions in different bands. Raman amplification is employed for the ULH band while Erbium-doped fiber amplification (EDFA) is used for both the LH and ULH bands. Optical circulators are employed for multiplexing and demultiplexing. This solution does not incur the ripple penalty of prior art solutions based on interferential filters while providing excellent isolation between the ULH and LH channels and bi-directional communication within a single fiber.
    Type: Grant
    Filed: March 15, 2002
    Date of Patent: March 18, 2008
    Assignee: Cisco Technology, Inc.
    Inventors: Alessandro Sguazzotti, Fransisco Martinez Rodriguez, Marco Mazzini
  • Patent number: 7321461
    Abstract: Provided are a broadband light source suitable for a pump light module for Raman amplification and a Raman amplifier which uses such light source. The broadband light source comprises a light source system for emitting light having two or more different output peak wavelengths and a nonlinear medium having an input port and an output port, and the nonlinear medium affords nonlinear effect on light emitted from the light source system and input from the input port, and outputs the resultant light as pump light from the output port. The Raman amplifier, which comprises an optical fiber for Raman amplification, a multiplexing module, and the broadband light source of the present invention, amplifies signal light propagating through the optical fiber for Raman amplification.
    Type: Grant
    Filed: November 4, 2003
    Date of Patent: January 22, 2008
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Motoki Kakui
  • Patent number: 7286283
    Abstract: Apparatus for optically pumping a clad amplifier fiber includes one or more transmission fibers arranged and configured to insert pump-light from a pump light source such as a diode-laser into the cladding of the amplifier fiber. The pump light propagates through the cladding and a portion of the pump light is absorbed in the doped core of the amplifier fiber. At least one of the transmission fibers is arranged to receive an unabsorbed portion of the propagated pump light from the amplifier cladding and re-insert the unabsorbed portion of the pump-light into the cladding for re-propagation through the cladding. This provides that pump light that would otherwise be wasted is circulated through the amplifier fiber for further absorption by the amplifier core.
    Type: Grant
    Filed: March 15, 2006
    Date of Patent: October 23, 2007
    Assignee: Coherent, Inc.
    Inventor: Andrei Starodoumov
  • Patent number: 7253944
    Abstract: A Raman amplifier having at least a first and a second optical Raman-active fiber disposed in series with each other is disclosed. A first pump source is connected to the first Raman-active fiber, and is adapted for emitting and coupling into the first Raman-active fiber a first pump radiation including a first group of frequencies. A second pump source is connected to the second Raman-active fiber, and is adapted for emitting and coupling into the second Raman-active fiber a second pump radiation including a second group of frequencies. The whole of the first and second group of frequencies extends over a pump frequency range having a width of at least 40% of the Raman shift. The minimum and the maximum frequency in each of the first and second group of frequencies differ from each other by at most 70% of the Raman shift.
    Type: Grant
    Filed: July 31, 2002
    Date of Patent: August 7, 2007
    Assignee: Pirelli & C. S.p.A.
    Inventors: Attilio Bragheri, Giulia Pietra, Raffaele Corsini, Danilo Caccioli
  • Patent number: 7242519
    Abstract: It is an object of the present invention to provide a Raman amplifier capable of easily reducing the wavelength deviation of a Raman gain while suppressing system performance degradation, and an optical transmission system using such a Raman amplifier.
    Type: Grant
    Filed: March 30, 2004
    Date of Patent: July 10, 2007
    Assignee: Fujitsu Limited
    Inventors: Kenichi Torii, Takao Naito, Toshiki Tanaka, Masahiro Yuki
  • Patent number: 7230958
    Abstract: Provided are a Raman amplifier and a Raman pumping method. A light source unit outputs a pumping light having a wavelength that periodically changes. A light intensity control unit varies a light intensity of the pumping light using the pumping light to improve the gain flatness of a Raman gain. A control unit directs the light intensity control unit to control the light intensity of the pumping light in synchronization with changes in the wavelength of the pumping light.
    Type: Grant
    Filed: April 28, 2004
    Date of Patent: June 12, 2007
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Sun Hyok Chang, Hee Sang Chung, Jin Soo Han, Ji Sung Jung, Heuk Park, Won Kyoung Lee, Hyun Jae Lee
  • Patent number: 7224513
    Abstract: A pumping light source unit for Raman amplification includes at least one pumping light source that outputs a first pumping light covering a current amplification band; at least one additional pumping light source that outputs a second pumping light covering an amplification band to be extended; and a setting control unit that controls a setting for a gain of an entire amplification band by resetting outputs of the first pumping light and the second pumping light. The pumping light source unit has a function of extending the amplification band in a stepwise manner.
    Type: Grant
    Filed: January 14, 2005
    Date of Patent: May 29, 2007
    Assignee: The Furukawa Electric Co., Ltd.
    Inventors: Atsushi Oguri, Yoshihiro Emori, Shu Namiki
  • Patent number: 7215836
    Abstract: The invention is in the field of distributed Raman amplification for digital and analog transmission applications and other applications, e.g., instrumentation and imaging applications, including HFC-CATV applications. In particular, the invention uses a high power broadband source of amplified spontaneous emission (ASE) as the Raman pump source for improved system performance. The invention also includes methods for constructing such a high-power broadband Raman pump.
    Type: Grant
    Filed: August 1, 2003
    Date of Patent: May 8, 2007
    Assignee: Ahura Corporation
    Inventors: Daryoosh Vakhshoori, Masud Azimi, Min Jiang, Kevin J. Knopp, Peidong Wang
  • Patent number: 7206124
    Abstract: Disclosed is a gain-providing optical power equalizer which can equalize optical channel output or gain while amplifying signal output. In prior art technologies, optical power equalization has been achieved by attenuating signal output differently depending upon optical channels. However, the optical power equalizer of the present invention is characterized in that it achieves equalization of optical power by giving optical gain differently depending upon optical channels. According to the present invention, the output of optical channels can be adjusted to be flat or as desired without deteriorating signal to noise ratio.
    Type: Grant
    Filed: March 20, 2003
    Date of Patent: April 17, 2007
    Assignee: Luxpert Technologies Co., Ltd.
    Inventors: Nam-Kyoo Park, Jung-Hoon Shin
  • Patent number: 7180654
    Abstract: Multi-wavelength light, including a plurality of segments of light signal with a different wavelength each, is inputted into a Raman amplification fiber. Pumping light generated by a pumping light source is supplied to the Raman amplification fiber in the opposite direction of the transmission direction of the multi-wavelength light. An auxiliary light source generates auxiliary light. An auxiliary light control circuit adjusts the optical power of the auxiliary light with a prescribed response time, based on the change in input power of the multi-wavelength light. The auxiliary light is supplied to the Raman amplification fiber in the same direction as the transmission direction of the multi-wavelength light.
    Type: Grant
    Filed: July 21, 2003
    Date of Patent: February 20, 2007
    Assignee: Fujitsu Limited
    Inventors: Yasushi Sugaya, Shinichirou Muro, Etsuko Hayashi
  • Patent number: 7130111
    Abstract: An optical amplifier comprises a device substrate, a first waveguide embedded in the device substrate, and a plurality of lasers. The lasers are positioned to provide a first plurality of light beams substantially transverse to the first waveguide.
    Type: Grant
    Filed: December 13, 2001
    Date of Patent: October 31, 2006
    Assignee: Intel Corporation
    Inventors: Andrew C. Alduino, Rongchung Tyan, Christopher J. Scholz
  • Patent number: 7095554
    Abstract: Optical pumping unit comprising a first pump source adapted to emit a first pump radiation at wavelength ?p1; a second pump source adapted to emit a second pump radiation at wavelength ?p2, with wavelength ?p2 different from wavelength ?p1; and a common coupling section comprising a first and a second port connected to the first and second pump source for respectively receiving the first and the second pump radiation; a third port for a signal radiation at wavelength ?s; a fourth port, wherein the coupling section is adapted to combine, in the fourth port, the signal radiation and the first and second pump radiation through a reversal of the direction of propagation of the first pump radiation from the first port to the fourth port.
    Type: Grant
    Filed: August 19, 2003
    Date of Patent: August 22, 2006
    Assignee: Avanex Corporation
    Inventors: Aurelio Pianciola, Marco De Donno, Paolo Milanese
  • Patent number: 7081989
    Abstract: Disclosed is a wide-band fiber amplifier for amplifying C-band and L-band optical signals, including a first amplifying unit including a first amplifying fiber adapted to be (1) pumped in at least one direction (2) amplify both the C-band and L-band optical signals and (3) output Amplified Spontaneous Emission (ASE), a second amplifying unit including a second amplifying fiber adapted to be pumped by amplified ASE and secondarily amplify the amplified L-band optical signal, and an L-band pumping light source including a third amplifying fiber adapted to be pumped in at least one direction while being pumped by the ASE, and output amplified ASE used to pump the second amplifying fiber.
    Type: Grant
    Filed: October 17, 2003
    Date of Patent: July 25, 2006
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Kwan-Woong Song, Jun-Ho Koh, Seong-Taek Hwang, Yun-Je Oh
  • Patent number: 7058301
    Abstract: A request method for performing optical power management to accomplish planned addition and removal of wavelengths in an optical communications system is disclosed, wherein each wavelength has a path of transmission through the system. The method comprises communicating a request for a power ramp to at least one path network component in the path, determining that the path network component has made preparations for the power ramp, and performing a power ramp in response to the determination. Further, a response method for performing power management to accomplish planned addition and removal of wavelengths in an optical communications system is disclosed, wherein each wavelength has a path of transmission through the system. The method comprises receiving a request for a power ramp, making preparations for the power ramp, determining that the power ramp has been completed, and resuming normal operation in response to the determination.
    Type: Grant
    Filed: February 28, 2002
    Date of Patent: June 6, 2006
    Inventors: Jonathan L. Bosloy, Lacra Pavel, Chris Passier, Matthew Brown
  • Patent number: 7027218
    Abstract: A thulium-doped fiber amplifier is disclosed and includes a thulium-doped fiber to amplify optical signals belonging to S-band, a first pumping unit to output amplified spontaneous emission that represents a peak value in a predetermined wavelength range belonging to C-band, to pump the thulium-doped fiber, and a second pumping unit to output pumping light belonging to the wavelength band different from the C-band to pump the thulium-doped fiber.
    Type: Grant
    Filed: August 1, 2003
    Date of Patent: April 11, 2006
    Assignee: Samsung Electronics Co. LTD
    Inventors: Seong-Taek Hwang, Yun-Je Oh
  • Patent number: 7019892
    Abstract: A wideband light source is disclosed. The wideband light source includes a first optical amplifier for generating and amplifying a C-band spontaneous emission light, a second optical amplifier for generating C-band and L-band spontaneous emission lights which is pumped by the C-band spontaneous emission light to amplify an L-band spontaneous emission light, and a reflector positioned between the first and second optical amplifiers to reflect the C-band spontaneous emission light provided from the first optical amplifier back to the first optical amplifier and the C-band and L-band spontaneous emission lights provided from the second optical amplifier back to the second optical amplifier.
    Type: Grant
    Filed: May 26, 2004
    Date of Patent: March 28, 2006
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Seong-Taek Hwang, Chang-Sup Shim, Yun-Je Oh
  • Patent number: 6989945
    Abstract: A long-throw, tight focussing optical coupler has a first passive optical element capable of coupling light between an optical source and an optical destination and a second passive optical element, capable of coupling light between the optical source and the optical destination, located between the first passive optical element and one of the optical source or the optical destination such that, a light beam from the optical source will be transferred to the optical destination when the optical source and optical destination are spaced apart by a distance.
    Type: Grant
    Filed: June 26, 2002
    Date of Patent: January 24, 2006
    Assignee: Xanoptix, Inc.
    Inventors: Keith Kang, John Trezza
  • Patent number: 6978063
    Abstract: An optical fiber amplifier module is disclosed which comprises a signal path located between a signal input and a signal output. A WDM coupler and an amplifying gain medium are disposed along the signal path. A pump laser is disposed out of the signal path in a manner that allows a pump signal from the pump laser to reflect off the WDM coupler and enter the signal path. An embodiment utilizing a second WDM coupler and a second pump laser is also disclosed.
    Type: Grant
    Filed: January 3, 2003
    Date of Patent: December 20, 2005
    Assignee: Photon-X, LLC
    Inventor: Renyuan Gao
  • Patent number: 6972898
    Abstract: Disclosed is a wide band optical fiber amplifier for amplifying C and L-band optical signal components having an economical configuration, high amplification efficiency while exhibiting a low noise figure. The amplifier includes first and second isolators; first, second, and third amplification units; a distributor; a gain flattening filter; and first and second reflectors. The amplifier receives C and L band optical signals and process the signals by: amplifying C and L band signals; gain flattening the only C band signal twice; amplifying C and L band signals for the second time; splitting the C band signal from L band signal; subjecting L band signal to be amplified three more times; and combining resulting C and L band signals.
    Type: Grant
    Filed: February 26, 2003
    Date of Patent: December 6, 2005
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Seong-Taek Hwang, Kwan-Woong Song
  • Patent number: 6967769
    Abstract: Optical systems of the present invention generally include at least one optical amplifier having a first pump source configured to supply power to said amplifier via a first pumping paths. A second pumping path is provided to supply power to the amplifier from a second pump source configured to replace power from the first pump source. The amplifier allows the replacement and repair of a pump source during operation by providing in-service hot swap capability, which increases the overall availability of the amplifier. The pump source can also be changed during operation to allow reconfiguration of the optical system.
    Type: Grant
    Filed: September 8, 2004
    Date of Patent: November 22, 2005
    Assignee: Corvis Corporation
    Inventors: Nabil M. Badr, Raymond Zanoni
  • Patent number: 6937389
    Abstract: An optical system including an optical amplifier having an optical coupler adapted for receiving and coupling pump radiation from a plurality of pump radiation sources. The gain profile of the amplifier being modified to employ optical couplers that are periodic in radiation wavelength with a period ??.
    Type: Grant
    Filed: December 13, 2002
    Date of Patent: August 30, 2005
    Assignee: Corvis Corporation
    Inventor: Nandakumar Ramanujam
  • Patent number: 6930825
    Abstract: An optical repeater is provided that includes at least four optical amplifiers each supplying optical amplification to an optical signal traveling in a different unidirectional optical fiber that collectively form at least two bi-directional pairs of optical fibers. The repeater also includes a first plurality of pump sources for providing pump energy to a first optical fiber located in a first of the optical fiber pairs and a second optical fiber located in a second of the optical fiber pairs. The first optical fiber and the second optical fiber support optical signals traveling in a common direction. A first combiner arrangement combines the pump energy from the first plurality of pump sources and distributes it to the optical amplifiers supplying amplification to optical signals traveling in the first and the second optical fibers.
    Type: Grant
    Filed: August 20, 2003
    Date of Patent: August 16, 2005
    Assignee: Red Sky Systems, Inc.
    Inventors: Jonathan A. Nagel, Michael J. Neubelt
  • Patent number: 6917731
    Abstract: According to one embodiment of the present invention an amplification module comprises a housing containing a plurality of optical ports. This housing: (i) at least partially encloses at least one amplification medium, (ii) provides at least one position for at least one optical filter, and (iii) includes a first optical port configured to provide both signal and pump light to the amplification module. According to an embodiment of the present invention the amplification module does not include a WDM for multiplexing pump light and signal light.
    Type: Grant
    Filed: March 27, 2002
    Date of Patent: July 12, 2005
    Assignee: Corning Incorporated
    Inventors: Kevin W Bennett, Jeffery A DeMeritt, Paul A Jakobson, Kenneth R Lane, Richard G Smart, Jason S Watts, Peter G Wigley
  • Patent number: 6914717
    Abstract: A nonlinear polarization amplifier stage includes a gain medium operable to receive a multiple wavelength optical signal. The amplifier further includes a pump assembly operable to generate a plurality of pump wavelengths forming a pump spectrum comprising a plurality of peaks. The amplifier also includes a coupler operable to introduce the at least one of the plurality of pump wavelengths to the gain medium to facilitate amplification of at least a portion of the multiple wavelength optical signal through nonlinear polarization. In one particular example, at least a wavelength or an intensity of the at least one of the plurality of pump wavelengths is manipulated to affect the shape of a gain curve associated with the multiple wavelength optical signal in the amplifier stage.
    Type: Grant
    Filed: July 1, 2002
    Date of Patent: July 5, 2005
    Assignee: Xtera Communications, Inc.
    Inventor: Mohammed N. Islam
  • Patent number: 6894831
    Abstract: A method of amplifying optical signals comprising providing a plurality of input radiation signals into the inputs of a P×V coupler, each of the input radiation signals having a respective input radiation profile having a set of pump wavelengths and pump powers corresponding to the respective wavelengths, wherein at least one set is different from at least one other set; providing V output pump radiation profiles from the outputs of the P×V coupler; and amplifying an optical data signal by coupling at least one of the V output pump radiation profiles with the optical data signal, wherein at least one of the V output pump radiation profiles has a different power than at least one other of the V output pump radiation profiles.
    Type: Grant
    Filed: August 29, 2003
    Date of Patent: May 17, 2005
    Assignee: Dorsal Networks, Inc.
    Inventors: William Shieh, Vladimir Petricevic, Thomas Clark
  • Patent number: 6882466
    Abstract: An optical amplifier is provided for performing amplification of optical signals of two wavelength bands, where deterioration in the optical SN ratio relative to one wavelength band is reduced, with a simple construction which can deal with restrictions on installation space, power consumption and the like. To this end, the present optical amplifier has a C/L band optical amplifying section for amplifying respective optical signals of a C band and an L band, a demultiplexer for demultiplexing output light from the C/L band optical amplifying section into the C band and the L band, an L band optical amplifying section for amplifying L band optical signals which have been demultiplexed by the demultiplexer, and a multiplexer for multiplexing the C band optical signals which have been demultiplexed by the demultiplexer and the L band optical signals which have been amplified by the L band optical amplifying section.
    Type: Grant
    Filed: August 9, 2000
    Date of Patent: April 19, 2005
    Assignee: Fujitsu Limited
    Inventors: Naomasa Shimojoh, Takao Naito
  • Patent number: 6850360
    Abstract: Fiber-optic communications systems are provided for optical communications networks. Fiber-optic communications links may be provided that use spans of transmission fiber to carry optical data signals on wavelength-division-multiplexing channels at different wavelengths. Raman pump light may be used to provide Raman amplification for the optical data signals. The Raman pump light may be used to make measurements on the spans of transmission fiber. Raman pump light may be modulated to make optical time domain reflectometry measurements and measurements of the Raman gain coefficient in the fiber. Information on the measurements made using the Raman pump light may be used to control the Raman pump light during operation of the communications link and may be provided to a network management system.
    Type: Grant
    Filed: May 4, 2001
    Date of Patent: February 1, 2005
    Assignee: Bookham, Inc.
    Inventors: Chien-Jen Chen, William S. Wong
  • Patent number: 6768577
    Abstract: A tunable multimode wavelength division multiplex Raman pump and amplifier, and a system, method, and computer program product for controlling a tunable Raman pump and amplifier. The tunability of the pump source is accomplished by either straining or heating an external fiber grating, thereby causing a different wavelength of light to be emitted by the pump source. The system includes a microprocessor-based controller that monitors an amplifier's performance and adjusts the drive current and/or wavelength of the tunable pumps of an amplifier to achieve a target performance.
    Type: Grant
    Filed: March 15, 2002
    Date of Patent: July 27, 2004
    Assignee: Fitel USA Corp.
    Inventors: Benjamin J. Eggleton, Paul Steinvurzel, Yoshihiro Emori, Shu Namiki, Akira Fujisaki, Toshio Kimura
  • Patent number: 6747792
    Abstract: A method of amplifying a signal light includes initially multiplexing a signal light and a pumping light, initially amplifying the signal light initially demultiplexing so as to separately output the amplified signal light and the pumping light, and modifying a waveform of the amplified signal light so as to compensate for waveform distortion of the signal light along a transmission path of the signal light and providing an output of a waveform modified signal light. Thereafter, the waveform modified signal lights is secondarily multiplexed, secondarily amplified, and secondarily demultiplexed with a waveform of amplified signal light being compensated for waveform distortion of the signal light along a transmission path of the signal light an output of a waveform modified signal light. The waveform modified signal light is thirdly multiplexed and thirdly amplified so as to provide an output of amplified waveform modified signal light.
    Type: Grant
    Filed: May 28, 2003
    Date of Patent: June 8, 2004
    Assignee: Hitachi, Ltd.
    Inventor: Hiroyuki Nakano
  • Patent number: 6741390
    Abstract: It is an object of the present invention to provide a variable wavelength light source apparatus capable of changing continuously wavelengths of a plurality of oscillation light over a wideband and an optical amplifier using the same.
    Type: Grant
    Filed: January 22, 2003
    Date of Patent: May 25, 2004
    Assignee: Fujitsu Limited
    Inventors: Miki Onaka, Etsuko Hayashi, Hiroshi Onaka
  • Patent number: 6731428
    Abstract: An arrangement for monitoring the performance of each pump source in a fiber Raman amplifier arrangement utilizes a set of unique “signature” signals, each signature signal impressed on a different pump input signal. At the receiver, the signature signals are extracted from the received, amplified signal. If a particular signature signal is missing at the receiver, this is indicative of failure of its associated pump source at the transmitter. If a particular signature signal is noticeable weaker than other received signature signals (as evidenced by, for example a low SNR or high BER), this is indicative of a power loss in its associated pump source. Since each signature signal is chosen to be unique, the identity of each pump source can be easily ascertained. In one embodiment, a low data rate signal is impressed on an RF signal used to modulate the pump prior to be applied to the transmission fiber.
    Type: Grant
    Filed: November 21, 2001
    Date of Patent: May 4, 2004
    Assignee: Lucent Technologies Inc.
    Inventor: Narayan L. Gehlot
  • Patent number: 6731425
    Abstract: Optical amplification bandwidth is improved by providing an economical and practical way of multiplexing together multiple Raman pump energy sources at disparate wavelengths. An arrayed waveguide grating (AWG) may be used to implement a double multiplexer. The insertion loss of the AWG is very low, allowing a reduction in the necessary power. Also, a single AWG may be used to combine numerous pump wavelengths.
    Type: Grant
    Filed: March 7, 2002
    Date of Patent: May 4, 2004
    Assignee: Cisco Technology, Inc.
    Inventors: Marco Mazzini, Eliana Silvia Vercelli, Federico Carniel
  • Patent number: 6728028
    Abstract: Improved systems and methods for optical amplification of WDM signals are provided. Multiple sub-bands of a WDM signal are amplified in a first common amplification stage and separated from one another. The separated sub-bands are amplified by independent parallel amplification stages. Each of the independent parallel amplification stages is equipped with a corresponding optical pump energy source. Furthermore, all of these optical pump energy sources together also provide the pump energy for the first common amplification stage. This architecture provides low noise figure and independent power regulation for each of the sub-bands while employing only N−1 pump energy sources for N amplification stages, thus greatly reducing space requirements and cost.
    Type: Grant
    Filed: July 30, 2001
    Date of Patent: April 27, 2004
    Assignee: Cisco Technology, Inc.
    Inventors: Fransisco Martinez Rodriguez, Marco Mazzini, Sara Gabba
  • Patent number: 6704136
    Abstract: A pumping source with a number of regulated pump lasers for broadband optical amplification of a WDM signal is provided, wherein, the powers of the pump lasers that exhibit different wavelengths are regulated such that all the channels of a WDM signal exhibit a flat profile of their levels at the end of the transmission fiber and in the event of a defect and, particularly, in the event of a failure or a partial failure of the pump lasers, the corresponding change in the gain profile is automatically compensated for by a supervisory regulation device for resetting the pumping powers in the event of a failure report, thereby resulting in a minimal change in the gain spectrum of all the channel levels of a WDM signal in the event of defective operation of the pumping source.
    Type: Grant
    Filed: January 16, 2002
    Date of Patent: March 9, 2004
    Assignee: Siemens Aktiengesellschaft
    Inventor: Richard Neuhauser
  • Publication number: 20040042060
    Abstract: An optical parametric amplifier (OPA) driven with at least two pump waves. The pump waves may be configured such that the OPA produces uniform exponential gain over a range of wavelengths that extends, for example, at least 30 nm on either side of the average pump-wave wavelength. In addition, since the Brillouin scattering limit applies to each pump wave independently, substantially twice the amount of energy may be pumped into an OPA of the present invention compared to that in the corresponding single pump-wave OPA of the prior art. An OPA of the present invention may be used in a WDM communication system and configured for simultaneous signal amplification and wavelength conversion.
    Type: Application
    Filed: August 30, 2002
    Publication date: March 4, 2004
    Inventors: Colin J. McKinstrie, Stojan Radic
  • Patent number: 6697193
    Abstract: An amplification architecture for WDM receiver systems. The WDM channel grid is divided into groups of adjacent channels. A separate optical amplifier is provided for each channel with a single pump being shared among the channels of each group. The gain experienced by channels of a given group may be adjusted by varying the power of the group's pump. This approach allows equalization of received channel power such that all channels fall within the desired dynamic range. The amplification architecture may be implemented in a space-efficient manner at low cost.
    Type: Grant
    Filed: June 6, 2001
    Date of Patent: February 24, 2004
    Assignee: Cisco Technology, Inc.
    Inventors: Fausto Meli, Roberta Castagnetti, Giorgio Grasso
  • Patent number: 6697192
    Abstract: An external-resonator laser system having multiple laser elements is configured to permit each laser to undergo individual amplification notwithstanding optical beam combination. In this way, overall output power may be scaled in a desired fashion, depending on the selected characteristics of the optical amplifier elements. To achieve additional power, each of the amplifiers may implemented as a phased array. Viewed more generally, a phased-array configuration affords beam combining in two stages, with each contributing input source itself composed of multiple sources whose outputs have been combined. If each phased-array source emits at a different wavelength, this design offers a multi-wavelength output whose power level may be scaled in accordance with the number and character of the devices forming each phased array.
    Type: Grant
    Filed: November 8, 2000
    Date of Patent: February 24, 2004
    Assignee: Massachusetts Institute of Technology
    Inventors: Tso Yee Fan, Anish Goyal, Antonio Sanchez-Rubio
  • Patent number: 6690507
    Abstract: A double pumped Raman amplifier is provided that increases gain over a same length of gain fiber without significantly increasing a percentage of noise. The amplifier may include a source of pump light coupled to the output end of a coil of Raman gain fiber, and a reflector coupled to the input end of the coil which may be either a mirror, or a fiber Bragg grating. Alternatively, a beam splitter may be connected to the source of pump light and the resulting split output may be coupled to both the input and output ends of the gain fiber. The increase in amplification efficiency allows the optical fiber used in components such as dispersion compensating modules to also be used as Raman gain fiber in such amplifiers.
    Type: Grant
    Filed: January 30, 2002
    Date of Patent: February 10, 2004
    Assignee: Corning Incorporated
    Inventors: Stuart Gray, Stephen C Guy, James R Passalugo
  • Publication number: 20030231380
    Abstract: An arrangement and method provide an optical thulium doped fiber amplifier utilizing a dual wavelength pumping scheme for amplifying an optical signal. The method includes the steps of: a first deposition (a) of energy into the fiber amplifier by pumping with radiation of a first wavelength; and a second deposition (b) of energy into the fiber amplifier by pumping with radiation of a second wavelength. The radiation of the first wavelength is arranged to induce, by single photon absorption, a population to the 3H4 level of the thulium dopant, and the radiation of the second wavelength primarily depopulates the 3F4 level, by excited absorption of a single photon, preferably by strong excited state absorption to the 3F2 level. The steps gives a population inversion between the 3H4 and the 3F4 levels and facilitate a power efficient high gain amplification.
    Type: Application
    Filed: March 10, 2003
    Publication date: December 18, 2003
    Inventors: Anderson Stevens Leonidas Gomes, Michael Lee Sundheimer, Mariana Torres Carvalho, Joaquim Ferreira Martins-Filho, Carmelo Jose Albanez Bastos-Filho, Walter Margulis
  • Publication number: 20030223106
    Abstract: Provided are an optical fiber amplification method and apparatus for controlling a gain. Initial values including target gains of first and second amplifications for an optical amplifier amplifying the input light signal are set. Power of the input light signal is measured and the power of first and second backward pump lights proceeding in the opposite direction to the input light signal is controlled based on the measured power. The input light signal is firstly amplified and a first amplification gain of the amplified light signal is calculated. Power of a first forward pump light proceeding in the same direction as the input light signal is controlled so that the first amplification gain can be substantially equal to the target gain of the first amplification. The firstly amplified light signal is secondly amplified and a second amplification gain with respect to the input light signal is calculated.
    Type: Application
    Filed: March 19, 2003
    Publication date: December 4, 2003
    Inventors: Jyung-chan Lee, Seung-il Myong, Moo-jung Chu, Hyun-jae Lee
  • Publication number: 20030206335
    Abstract: An EDFA with integrated input and output modules is presented. The integrated input module has a packaged pump laser diode mounted to the metal EDFA package to provide a heat sink for the pump laser diode which sends the pump laser light over a optical fiber section connected to the amplifying erbium-doped optical fiber section. The fiber section is formed from an optical fiber which better matches the transmission modes in the erbium-doped optical fiber section and has an end subsection of the single mode fiber for a larger numerical aperture. Collimating lenses also increase the coupling efficiency of the laser diode to the erbium-doped fiber section. The integrated output module has a photodiode with a tap filter to monitor the output power of the EDFA, an optical isolator to prevent interference in the erbium-doped optical fiber section. With a twin optical isolator, the integrated input and output modules can be arranged in different ways and combinations with the erbium-doped optical fiber section.
    Type: Application
    Filed: May 3, 2002
    Publication date: November 6, 2003
    Applicant: Lightwaves 2020, Inc.
    Inventors: Jing-Jong Pan, Xiangdong Qiu, Kejian Guan, Mingjie Zhang
  • Patent number: 6643058
    Abstract: Optical pumping unit comprising a first pump source adapted to emit a first pump radiation at wavelength &lgr;p1; a second pump source adapted to emit a second pump radiation at wavelength &lgr;p2, with wavelength &lgr;p2 different from wavelength &lgr;p1; and a common coupling section comprising a first and a second port connected to the first and second pump source for respectively receiving the first and the second pump radiation; a third port for a signal radiation at wavelength &lgr;s; a fourth port, wherein the coupling section is adapted to combine, in the fourth port, the signal radiation and the first and second pump radiation through a reversal of the direction of propagation of the first pump radiation from the first port to the fourth port.
    Type: Grant
    Filed: December 20, 2001
    Date of Patent: November 4, 2003
    Assignee: Avanex Corporation
    Inventors: Aurelio Pianciola, Marco De Donno, Paolo Milanese
  • Patent number: 6636346
    Abstract: Disclosed is an optical amplifier, comprising: at least one optically amplifying unit having: a forward excitation light source for generating a forward excitation light; a forward excitation light coupler for coupling the forward excitation light with an input optical signal; an optically amplifying medium for amplifying the input optical signal combined with the forward excitation light; a backward excitation light source for generating a backward excitation light; a backward excitation light coupler for coupling the backward excitation light with the amplified optical signal; a first controller for controlling the forward excitation light source to generate the forward excitation light with a power up to a maximum power thereof; and a second controller for controlling the backward excitation light source to generate the backward excitation light in such a way that the backward excitation light compensates gain deficiency as compared with a desired gain of the optical amplifier.
    Type: Grant
    Filed: December 17, 2001
    Date of Patent: October 21, 2003
    Assignee: NEC Corporation
    Inventor: Kouiti Akiyama
  • Patent number: 6636345
    Abstract: The optical fiber pumping system includes a connector that is adapted to selectively communicate with an external pump system. The connector communicates with an onboard pump multiplexer which also receives input from an on-board pump via a connector. The on-board pump may be hot swapped by connecting an external pump system to the connector and coordinating the power up of the external pump system with the power down of the on-board pump to replace a failed on-board pump with a new pump.
    Type: Grant
    Filed: February 27, 2001
    Date of Patent: October 21, 2003
    Assignee: Corning Incorporated
    Inventor: Martin Hempstead