Monitoring Patents (Class 398/177)
  • Patent number: 7751726
    Abstract: Systems and methods for operating transponders that automatically accommodate multiple received signal types. The different signal types may include different clients such as, e.g., SONET/SDH, G.709, 10 Gigabit Ethernet, etc. as well as different data rates. A transponder can automatically detect the client signal type and data rate and respond by processing the received signal appropriately, notifying a control processor, and invoking an appropriate performance monitoring method. This maximizes the network operator's flexibility and ease of configuration.
    Type: Grant
    Filed: March 10, 2009
    Date of Patent: July 6, 2010
    Assignee: Cisco Technology, Inc.
    Inventors: Maurizio Gazzola, Emanuela Grandi, David Bianchi, Stefano Binetti, Luca Della Chiesa
  • Patent number: 7729620
    Abstract: Methods and systems for controlling optical power attenuation are provided. A method comprises periodically measuring an optical power of an optical signal received by an optical receiver and periodically measuring a first attenuation control signal voltage. When the optical power measurement is outside a target power range, the method continues with calculating a target voltage necessary to maintain the optical power measurements at a target power level; calculating a second attenuation control signal based on the target voltage, wherein the second attenuation control signal is calculated to provide an over-damped transient response that maintains the second attenuation control signal within a usable range of a variable optical power attenuator; applying a second attenuation control signal voltage based on the second attenuation control signal to the variable optical power attenuator; and adjusting attenuation of the optical signal based on the second attenuation control signal voltage.
    Type: Grant
    Filed: September 29, 2005
    Date of Patent: June 1, 2010
    Assignee: ADC Telecommunications, Inc.
    Inventors: Paul Schatz, Dean Zavadsky, William J. Mitchell, Steve Stuart, Ana Santos
  • Patent number: 7725042
    Abstract: An automated optical transport system is provided which provides for automatic discovery of system components, automatic inventory of system components, automatic topology detection, automatic provisioning of channels, and automatic characterization and tuning of system components and fiber. The invention provides automation capability through inclusion of management card capabilities at each station which communicates through a reverse propagating service channel. Dynamic and propagation direction independent segments are provided in conjunction with a token-based scheme to repeatedly tune, update and monitor the transport system.
    Type: Grant
    Filed: April 22, 2003
    Date of Patent: May 25, 2010
    Inventors: Marvin Ray Young, Michael H. Eiselt, Daniel Nooner, Jeffrey Pearlman, Michael L. Cooper
  • Patent number: 7715710
    Abstract: Methods and apparatus for optical-power control in an optical network employing wavelength-division multiplexed (WDM) optical-fiber links are devised to circumvent the effect of crosstalk caused by optical-power scattering. Each carrier signal is amplitude-modulated by an identifying tone, with the power of an identifying tone having a predetermined ratio to the power of its carrier signal. A fiber span within an optical-fiber link is tapped at a preferred monitoring point, and the power spectrum of the envelope of the tapped optical signal is measured. To estimate an individual carrier power, a temporary gain is applied and the power of a corresponding tone is measured. To control optical power of each wavelength carrier in several spans in the network, a network controller selects an order of processing the spans of interest, and selects the order of processing of each channel within each span.
    Type: Grant
    Filed: May 29, 2007
    Date of Patent: May 11, 2010
    Assignee: Alcatel Lucent
    Inventors: Ping Wai Wan, Derrick Remedios
  • Patent number: 7697845
    Abstract: An optical add-drop function part of an optical add-drop multiplexer has an output end of transmitted light signal in which an optical termination mechanism formed by an optical detector for detecting open of an optical fiber, an optical switch, and an optical terminator are mounted. Further, a reflection level calculation circuit, a reflection warning determination circuit, and an optical switch selection circuit are mounted to perform laser safety in the optical add-drop function part as well. The laser safety part in the optical add-drop function part is operated earlier than the laser safety part in an optical amplification function part.
    Type: Grant
    Filed: May 23, 2007
    Date of Patent: April 13, 2010
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Yasuhiro Uchiyama, Hiroyuki Nakano
  • Patent number: 7697842
    Abstract: An automated optical transport system is provided which provides for automatic discovery of system components, automatic inventory of system components, automatic topology detection, automatic provisioning of channels, and automatic characterization and tuning of system components and fiber. The invention provides automation capability through inclusion of management card capabilities at each station which communicates through a reverse propagating service channel. Dynamic and propagation direction independent segments are provided in conjunction with a token-based scheme to repeatedly tune, update and monitor the transport system.
    Type: Grant
    Filed: August 31, 2006
    Date of Patent: April 13, 2010
    Inventors: Marvin Ray Young, Michael H. Eiselt, Daniel Nooner, Jeffrey Pearlman, Michael L. Cooper
  • Patent number: 7689131
    Abstract: A WDM system includes a plurality of P to P WDM systems connected for wavelength-multiplexing optical signals of a plurality of wavelengths, transmitting them to a transmission path, transmitting wavelength-division multiplexed light while performing amplification by using optical AMP in the transmission path, and subjecting the wavelength-division multiplexed light to wavelength isolation at the reception side. An OSC which is a monitoring control signal such as a normal optical signal is used closely within one P to P WDM system. However, by transmitting and receiving the OSC between a plurality of P to P WDM systems, it is possible to solve a problem at the system rise. Moreover, since accumulative OSNR data is transmitted up to the P to P WDM system of the final stage, it is possible to detect an accurate OSNR value and a leak ASE light quantity at the end side.
    Type: Grant
    Filed: November 11, 2003
    Date of Patent: March 30, 2010
    Assignee: Fujitsu Limited
    Inventors: Kimio Uekama, Takehiro Fujita, Motoyoshi Sekiya
  • Patent number: 7684711
    Abstract: An optical transmission system comprises two optical fibers carrying optical signal traffic between two terminals, and a plurality of optical repeaters coupled to the two fibers each repeater having a permanently connected passive high loss loop back circuit between the two fibers. One terminal includes a transmitter, which launches a pulsed supervisory signal on a dedicated supervisory wavelength into one optical fiber, and a receiver, which detects a portion of the supervisory signal looped back from each repeater in order to identify the existence and location of faults in the transmission system. The pulsed supervisory signal is of sufficiently short duration such that portions of the signal returned from each repeater do not overlap with one another and interference with the counter-propagating traffic is avoided by utilizing a dedicated supervisory wavelength. Each return pulse is integrated sequentially by a single detector and processed by heterodyne reception and synchronous demodulation.
    Type: Grant
    Filed: April 21, 2005
    Date of Patent: March 23, 2010
    Assignee: Xtera Communications, Inc.
    Inventors: Steve Desbruslais, John Ellison, David Powell
  • Patent number: 7680419
    Abstract: A repeater is disclosed that transmits an optical signal using wave division multiplexing. The repeater includes a demultiplexing unit that separates plural channels contained in the optical signal, an adjusting unit that adjusts at least optical power of each of the channels according to a control signal, a multiplexing unit that outputs a multiple wavelength signal in which the channels are multiplexed, and a monitoring unit that determines a modulation scheme and a bit rate of the optical signal for each of the channels so as to generate the control signal.
    Type: Grant
    Filed: June 2, 2006
    Date of Patent: March 16, 2010
    Assignee: Fujitsu Limited
    Inventors: Hisao Nakashima, Takeshi Hoshida
  • Patent number: 7680412
    Abstract: A method and device for determining in-band noise of an optical signal. The optical signal is split to produce two optical signal components, of distinct polarisation, such that the respective noise component in each signal component is uncorrelated. The optical signal components are converted to the electrical domain to produce electrical signal components. The signal component powers are equalised either in the optical domain or the electrical domain. The equalised electrical signal components are then subtracted together to cancel the correlated portions of the signal components (e.g. the data signal), such that only uncorrelated signal components (e.g. noise) are output for measurement.
    Type: Grant
    Filed: April 28, 2006
    Date of Patent: March 16, 2010
    Assignee: National ICT Australia Limited
    Inventors: Trevor Anderson, Sarah Dods
  • Patent number: 7676152
    Abstract: In an optical telecommunication system in which an intensity of an arriving optical signal is different for each packet, detected is an optical intensity for each packet with little error. For this purpose, contrived is to detect an average optical intensity across header parts for each packet by focusing on the fact that the header part comprising the preamble and delimiter of a packet is in a bit pattern which includes approximately the same numbers of “0” and “1”.
    Type: Grant
    Filed: September 28, 2006
    Date of Patent: March 9, 2010
    Assignee: Fujitsu Limited
    Inventors: Tetsuji Yamabana, Kazuyuki Mori, Satoshi Ide
  • Patent number: 7676160
    Abstract: The present invention aims at providing a technique capable of supervising and controlling optical repeaters, without affecting transmission characteristics and wavelength bands of signal lights, by utilizing the Raman effect. To this end, the present invention provides a supervisory controlling system of an optical repeater, in an optical amplifying-and-repeating transmission system for amplifying and repeatingly transmitting signal light propagated through an optical transmission path by the optical repeater, wherein the supervisory control signal light is amplified due to the Raman effect by the signal light acting as excitation light in an optical transmission path (Raman amplifying medium), to thereby supervise and control the optical repeater in accordance with the thus Raman amplified supervisory control signal light.
    Type: Grant
    Filed: March 12, 2002
    Date of Patent: March 9, 2010
    Assignee: Fujitsu Limited
    Inventor: Kenji Ohta
  • Patent number: 7668459
    Abstract: In a wavelength division multiplexing optical transmission system, in order to know an influence amount of a temperature dependency of a dispersion slope, a method of monitoring a dispersion variation amount in two or more of wavelength channels is provided. Further, a method of compensating a wavelength dependency of a temperature dependency of the dispersion by providing an appropriate dispersion individually to the channels or summarizingly for all of bandwidths based on the monitored dispersion variation amounts is provided. According to the present invention, in the WDM optical transmission system, a deterioration in a transmission characteristic by influence of a temperature variation of the dispersion slope can be reduced.
    Type: Grant
    Filed: July 21, 2003
    Date of Patent: February 23, 2010
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Tetsuro Inui, Hidehiko Takara, Takashi Yamamoto
  • Publication number: 20100040367
    Abstract: An economical optical network is constituted by effectively using network resources by using the minimum number of, or minimum capacity of 3R repeaters. 3R section information corresponding to topology information on the optical network to which an optical node device itself belongs is stored, and the 3R section information stored is referred so as to autonomously determine whether or not the optical node device itself is an optical node device for implementing the 3R relay when setting an optical path passing through the optical node device itself. Alternatively, when the optical node device itself is a source node, another optical node device for implementing the 3R relay among the other optical node devices through which the optical path from the optical node device itself to the destination node passes is identified, and this identified optical node device is requested to implement the 3R relay when setting an optical path in which the optical node device itself is a source node.
    Type: Application
    Filed: October 20, 2009
    Publication date: February 18, 2010
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Eiji OKI, Akira MISAWA, Masaru KATAYAMA, Satoru OKAMOTO
  • Patent number: 7657187
    Abstract: An optical transmission apparatus for amplifying and relaying a wavelength-division-multiplexed optical signal includes (1) a variation-detecting unit which detects varying speed of input power of the wavelength-division-multiplexed optical signal and compares the varying speed with a set value, (2) an optical amplifying unit which amplifies the wavelength-division-multiplexed optical signal at a fixed amount of amplification, (3) a variable optical attenuating unit which variably attenuates the wavelength-division-multiplexed optical signal, (4) and a controlling unit which controls attenuation amount of the variable optical attenuating unit in accordance with the varying speed.
    Type: Grant
    Filed: March 8, 2006
    Date of Patent: February 2, 2010
    Assignee: NEC Corporation
    Inventor: Katsuhiko Shimizu
  • Patent number: 7643759
    Abstract: Provided are a signal-quality evaluation device and a signal adjustment method which require shorter evaluation time and which have high flexibility of application. A signal quality evaluation device 100 includes an optical component 110 and an optical output detector 120. In the optical component 110, an output optical power Pout is a function of an input optical power Pin, and this function Pout(Pin) has at least one maximum point. The optical output detector 120 detects the time-average power of light output from the optical component 110.
    Type: Grant
    Filed: January 12, 2006
    Date of Patent: January 5, 2010
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Masato Tanaka
  • Publication number: 20090324249
    Abstract: Various high loss loop back (HLLB) repeater architectures are disclosed that enable selectively monitoring (e.g., measuring, analyzing, etc) of Rayleigh signals from both inbound and outbound directions of an optical communication system. In one such embodiment, first and second optical test signal frequencies (or ranges) are used, in conjunction with selective filtering, for monitoring the outbound and inbound paths, respectively. The repeater architectures allow optical time domain reflectometry (OTDR) monitoring techniques to be employed, for example, in particularly long repeater spans, such as those in excess of 90 km in length.
    Type: Application
    Filed: June 26, 2008
    Publication date: December 31, 2009
    Applicant: TYCO TELECOMMUNICATIONS (US) INC.
    Inventor: Hongbin Zhang
  • Patent number: 7630649
    Abstract: An economical optical network is constituted by effectively using network resources by using the minimum number of, or minimum capacity of 3R repeaters. 3R section information corresponding to topology information on the optical network to which an optical node device itself belongs is stored, and the 3R section information stored is referred so as to autonomously determine whether or not the optical node device itself is an optical node device for implementing the 3R relay when setting an optical path passing through the optical node device itself. Alternatively, when the optical node device itself is a source node, another optical node device for implementing the 3R relay among the other optical node devices through which the optical path from the optical node device itself to the destination node passes is identified, and this identified optical node device is requested to implement the 3R relay when setting an optical path in which the optical node device itself is a source node.
    Type: Grant
    Filed: March 12, 2004
    Date of Patent: December 8, 2009
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Eiji Oki, Akira Misawa, Masaru Katayama, Satoru Okamoto
  • Patent number: 7620273
    Abstract: A technique for improving optical cross-connections comprises placing a switch in front of a number of processing units. So configured, the units are no longer dedicated to a specific link or signal. When necessary, a unit is connected/disconnected to one or more optical links by the switch to carry out any number of processing functions, such as regeneration, Raman pumping, dispersion equalization/compensation or performance monitoring. Because the units are no longer dedicated to specific links the cost of the cross-connections and the network it is a part of can be reduced.
    Type: Grant
    Filed: February 14, 2002
    Date of Patent: November 17, 2009
    Assignee: Alcatel-Lucent USA Inc.
    Inventors: Bharat Tarachand Doshi, Stefan Hunsche, Ramesh Nagarajan, Srinivasa Prasanna, Narayan Raman, Meenakshi Sharma
  • Patent number: 7606488
    Abstract: In a wavelength-division-multiplexing optical transmission system in which optical-node apparatuses that perform relay transmission of wavelength-division-multiplexed light are located at specified nodes in a main optical transmission path, an optical amplifier switches level control to constant-gain control when there is a notification of a change in the number of multiplexed wavelengths, and then after a specified amount of time restarts level control so that the level becomes a target level that corresponds to the actual number of wavelengths.
    Type: Grant
    Filed: September 29, 2006
    Date of Patent: October 20, 2009
    Assignee: Fujitsu Limited
    Inventor: Yasushi Sugaya
  • Patent number: 7606487
    Abstract: The distortion component of an optical signal received from an optical transmission system, such as an all-optical system, subject to noise and amplitude distortion components, can be evaluated by a method that utilises information derived from analysing the bit error ratio (BER) of the signal as a function of a movable threshold. The analysis is performed in high and low bit error ratio areas of the eye diagram used for data one/zero decision making. The intersections with the threshold axis (where BER=0.25) of extrapolations of the high and low bit error ratio values provide variables V1 and V2 which are divided (V1/V2) to obtain an estimate/prediction of the amplitude closure of the eye diagram resulting from amplitude distortion. The analysis is preferably carried out after Q conversion of the BER values. The method can also be extended to provide indications of Q, bit error ratio and optical signal-to-noise ratio within the signal.
    Type: Grant
    Filed: October 9, 2001
    Date of Patent: October 20, 2009
    Assignee: Nortel Networks Limited
    Inventors: Peter J Anslow, Richard W Heath
  • Patent number: 7593640
    Abstract: A method of dynamically adjusting an optical module in an optical system including a plurality of transmission channels includes the following steps: measuring the quality of the optical signal at the output of the system as defined by an error function, varying an optical parameter of at least one module of the system, measuring a differential error introduced by each variation on the error function of the optical signal at the output of the system, estimating an operating point of the system corresponding to an expected reduction of the error function, and adjusting a parameter of an optical module toward the operating point of the system.
    Type: Grant
    Filed: November 15, 2002
    Date of Patent: September 22, 2009
    Assignee: Alcatel Optronics France
    Inventor: Dominique Hamoir
  • Patent number: 7574138
    Abstract: A device (D2) is dedicated to controlling degradation parameters associated with signals on channels with different wavelengths, possibly arranged in bands of channels, and transmitted by transmission lines (Lj) connecting nodes (Ni) of a transparent optical communication network. The device includes processing means (PM2) adapted, in the event of transmission of signals of at least two channels or bands of channels by at least one transmission line (Lj), to measure for each of said channels or each of said bands of channels, firstly, the value of a parameter representative of the degradation of the signals on the corresponding line (Lj) and, secondly, taking account of said measured values, a power profile to be imposed on the signals so that they have predetermined degradation parameter values.
    Type: Grant
    Filed: January 9, 2004
    Date of Patent: August 11, 2009
    Assignee: Alcatel
    Inventors: Jean-Paul Faure, Vincent Bouder
  • Patent number: 7567758
    Abstract: A transceiver module having intergrated eye diagram opening functionality for reducing jitter is describe. The transceiver module may transmitter eye opener and a receiver eye opener integrated in a single circuit. The transceiver module may also include serial control and various other integrated components. Other functionalities that may be integrated on the transceiver module include loopback modes, bypass features, bit error rate testing, and power down mode.
    Type: Grant
    Filed: July 28, 2003
    Date of Patent: July 28, 2009
    Assignee: Finisar Corporation
    Inventors: Lewis B. Aronson, Rudy Hofmeister, Christopher Madden, Mark Farley, Dan Case, Tom Lenosky
  • Patent number: 7565083
    Abstract: An optical network route and method are disclosed that mitigate distortion in a route having different types of fibers. For an optical network route that includes a plurality of fiber spans of a first type and a fiber span of a second type, assume that the optical network route is transporting optical signals having a plurality of original wavelengths where one or more of the original wavelengths is in a distortion wavelength region of the second type of fiber span. For optical signals entering the second type of fiber span, the original wavelength that is in the distortion wavelength region of the second type of fiber span is shifted to a temporary wavelength outside of the distortion wavelength region. The optical signals then travel over the second type of fiber span. For optical signals exiting the second type of fiber span, the temporary wavelength is shifted back to the original wavelength.
    Type: Grant
    Filed: June 22, 2004
    Date of Patent: July 21, 2009
    Assignee: Sprint Communications Company L.P.
    Inventor: Youichi Akasaka
  • Patent number: 7561796
    Abstract: An optical transmission system for transmitting optical signals in which signals at different bit rates coexist, includes an optical sending apparatus for, when one or more faults are detected in a signal for transmission, generating a fault information signal with one frequency set in advance in accordance with the faults, converting the fault information signal into an optical signal, and sending out the optical signal, an optical transmission line for transmitting the optical signal sent out from the optical sending apparatus, and an optical receiving apparatus for receiving the optical signal transmitted through the optical transmission line, converting the received optical signal into an electric signal, detecting the fault information signal from the electric signal, and halting output of the electric signal to the outside.
    Type: Grant
    Filed: June 30, 2006
    Date of Patent: July 14, 2009
    Assignee: NEC Corporation
    Inventor: Makoto Ishiguro
  • Patent number: 7554721
    Abstract: A pumping unit supplies pumping light to a fiber connecting medium; a light monitoring unit detects light power of multiple-wavelength light; and a control unit controls the pumping light based on light power detected by the light monitoring unit and connecting medium information indicating optical characteristics in the connecting medium. The connecting medium information includes information indicating a fiber type of the fiber connecting medium, information indicating a length of the fiber connecting medium, an average fiber loss coefficient of the fiber connecting medium and an intra-station loss value.
    Type: Grant
    Filed: July 2, 2004
    Date of Patent: June 30, 2009
    Assignee: Fujitsu Limited
    Inventors: Maki Hiraizumi, Yoshio Shimano, Masao Nakata
  • Patent number: 7551852
    Abstract: A method and apparatus configured to transmit module data between optic modules over a primary communication channel, such as an optic fiber configured to carry network data or outgoing data. A control center may send the module data, such as any type of DDMI data, over the optic fiber to control one or more aspects of the optic module system. The optic module may also be configured to send module data regarding any aspect of module status or operation, to a control center, via the optic fiber. Use of the primary communication channel, normally reserved for only network data, allow for module to module communication or module to control center communication without need of cumbersome two wire interface or supplement channels. Optic module data communication may occur concurrent with network data transmission. Optic module data back-up may occur via the optic channel to provide rapid re-load of important optic module data.
    Type: Grant
    Filed: July 15, 2005
    Date of Patent: June 23, 2009
    Assignee: Mindspeed Technologies, Inc.
    Inventors: Maurice M. Reintjes, Daniel Draper, Gilberto I. Sada
  • Patent number: 7551857
    Abstract: An optical amplifier may be quickly returned from a shutdown state to a regular state after getting recovery information of a fault. Gain setting by ASE is conducted to the repeaters on the up-stream side during the shutdown state, by outputting ASE light with the same intensity as the WDM signal. Accordingly, before realizing the recovery of shutdown, the gain setting is completed with the light whose intensity is within the safe criterion. After realizing the recovery of shutdown, the optical transmission system can be returned quickly to the regular operating state after recovery of shutdown state.
    Type: Grant
    Filed: July 11, 2005
    Date of Patent: June 23, 2009
    Assignee: Fujitsu Limited
    Inventors: Tougo Fukushi, Hideaki Sugiya, Akira Yamamoto, Masanori Kondoh
  • Patent number: 7539413
    Abstract: The present invention discloses a submarine observation system in which a plurality of carrier lights assigned to each submarine observation equipment is transmitted from a land terminal apparatus to an optical submarine cable (down-going) by using a WDM transmission. In the submarine observation equipment, only a prescribed carrier light is demultiplexed by an optical demultiplexer, an observation signal indicating an observation result is generated by an observation device, intensity of the carrier light demultiplexed by the optical demultiplexer is modulated by an optical amplifier based on an observation signal, and the modulated carrier light is multiplexed by an optical multiplexer. The multiplexed carrier light is output to the optical submarine cable (up-going) to be returned to the land terminal apparatus being the transmission station.
    Type: Grant
    Filed: March 14, 2005
    Date of Patent: May 26, 2009
    Assignees: Mitsubishi Denki Kabushiki Kaisha, Independent Administrative Institution, Japan Agency for Marine-Earth Science and Technology
    Inventors: Hiroaki Munehira, Junichi Nakagawa, Toshiyuki Tokura, Kenichi Asakawa, Hitoshi Mikada, Katsuyoshi Kawaguchi
  • Patent number: 7536110
    Abstract: In the WDM systems, the OSNR and the signal loss among the optical signals are substantially minimized at the receiving terminal to combat the SRS effects. An equal amount of the signal loss is expected for every span in the transmission path so that the optical amplifier gain tilt is not affected among a number of wavelength frequencies in the optical signal. This is accomplished by controlling the amplification process according to a feedback from the monitoring units for monitoring the optical signal.
    Type: Grant
    Filed: May 10, 2007
    Date of Patent: May 19, 2009
    Assignee: Hitachi, Ltd.
    Inventors: Tetsuya Uda, Hiroshi Masuda, Hirofumi Nakano, Eita Miyasaka, Satoshi Asamizu
  • Patent number: 7526199
    Abstract: An optical transmission apparatus includes a demultiplexer for separating wavelength-division multiplexing light received from a first optical transmission line into signals of different wavelengths to transmit the signals to an outside and a multiplexer for multiplexing signals of different wavelengths received from the outside to transmit multiplexed signals to a second optical transmission line. An input check unit is provided for monitoring a power level of a signal separated by the demultiplexer and for providing an output indicative thereof. An output adjuster is provided for intercepting a signal from the outside so as to inhibit receipt of the signal from the outside by the multiplexer depending on the output of the input check unit.
    Type: Grant
    Filed: July 20, 2005
    Date of Patent: April 28, 2009
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Kenro Sekine, Junya Kosaka, Tadashi Matsuoka
  • Patent number: 7522835
    Abstract: In a wavelength division multiplexed (WDM) optical communication system having optical transmitters and receivers communicating via a optical channels, the bit error rate (BER) for the optical channels is tested simultaneously by performing a BER measurement for the cascaded chain. A BER test signal is supplied from a BER tester to a first optical transmitter. The BER test signal passes through the optical channels. The last optical receiver in the cascaded chain supplies the test signal to the BER tester measure the BER. The measured BER is compared to a predetermined system BER threshold to determine if the optical channels meet their specified BER values. Each optical transmitter and receiver includes a performance monitoring circuit that monitors the quality of the BER signal supplied to the optical transmitter/receiver for identifying one or more optical channels that the measured BER exceeds a predetermined system BER threshold.
    Type: Grant
    Filed: April 17, 2000
    Date of Patent: April 21, 2009
    Assignee: Ciena Corporation
    Inventors: Jarod Guertin, Michael J. Ransford
  • Patent number: 7519300
    Abstract: In an optical transmission node network in which a first optical transmission node is connected with a second optical transmission nodes through an optical fiber cable and automatic optical output (APSD: Automatic Power Shut-Down) control is activated, after the APSD control is brought into an inhibited status, if an optical conduction to the second optical transmission node is detected, the APSD control inhibited status is canceled. In this way, if an optical transmission fiber is resorted (reconnected) after optical output power measurement or the like is carried out, the APSD control inhibition status (invalid status) is canceled for automatically restoring the APSD control activated status. Thus, optical output can be prevented from being inadvertently emitted at a high energy level from the optical fiber cable.
    Type: Grant
    Filed: June 7, 2004
    Date of Patent: April 14, 2009
    Assignee: Fujitsu Limited
    Inventors: Toshihiro Ohtani, Masaki Sato
  • Patent number: 7502565
    Abstract: A laser filter circuit includes an input terminal configured to receive an input laser signal and a first filter chain configured to generate a filtered signal. The first filter chain is coupled to the input terminal and has one or more filters connected in series. Each filter includes one or more adjustable capacitor networks. An adjustable capacitor controller generates one or more capacitor switch control signals based on an operating frequency of the input laser signal. The one or more control signals are for adjusting the capacitance of the one or more adjustable capacitor networks in the first filter chain. A plurality of output terminal output the filtered signal from the first filter chain.
    Type: Grant
    Filed: March 4, 2005
    Date of Patent: March 10, 2009
    Assignee: Finisar Corporation
    Inventor: Timothy G. Moran
  • Patent number: 7499648
    Abstract: A method and apparatus for signal amplification and decision device operation on a signal which has a magnitude, peak value, or other average power that varies over time. In general, a peak detector detects the peak value of a received signal and responsive to the peak value, selectively enables a decision device when the signal is amplified to increase decision device accuracy. The decision may occur before the amplification forces the signal into saturation. Multi-stage amplification in combination with controlled switching or multiplexing may be utilized to selectively amplify the signal and selectively initiate decision device operation. The peak detector value may also control signal amplification levels in a multi-stage amplifier. Responsive to the peak value, a switch, which receives as its input the output from one or more amplifier stages, may be controlled to output the signal after a desired amount of amplification.
    Type: Grant
    Filed: September 27, 2004
    Date of Patent: March 3, 2009
    Assignee: Mindspeed Technologies, Inc.
    Inventors: Daniel S. Draper, Charles E. Chang, Wim F. Cops
  • Patent number: 7496296
    Abstract: Terminal equipment of a wavelength division multiplexing optical transmission system is provided with a monitoring apparatus for monitoring optical transmission paths with an OTDR. For this monitoring, OTDR probe lights of different wavelengths are allocated to optical fibers and optical amplifier-repeaters, which are elements constituting the optical transmission paths. Further, different wavelengths are allocated to OTDR probe lights between the up link and the downlink. Such a wavelength as makes the wavelength dispersion over the optical transmission paths negative (usually the shorter wavelength side than the zero dispersion wavelength of the optical transmission paths) is allocated to the OTDR probe light for optical fiber monitoring, and a wavelength longer than 1550 nm is allocated to the OTDR probe light for optical amplifier-repeater monitoring.
    Type: Grant
    Filed: August 22, 2001
    Date of Patent: February 24, 2009
    Assignee: NEC Corporation
    Inventor: Yukio Michishita
  • Patent number: 7489876
    Abstract: The present invention is aimed at providing a low-cost optical transmission system of simple configuration, capable of achieving a satisfactory OSNR even in the time of transmission of a small number of wavelengths. To this end, the optical transmission system is provided with a noise elimination unit corresponding to each of optical amplifiers arranged on a transmission path. This noise elimination unit includes a transmission characteristic capable of selectively transmitting a light in a wavelength band in which a signal light exists through an amplification band of the optical amplifier, and includes a function of automatically eliminating a noise light in a wavelength band in which a signal light does not exist, of noise lights generated in the optical amplifiers.
    Type: Grant
    Filed: July 30, 2004
    Date of Patent: February 10, 2009
    Assignee: Fujitsu Limited
    Inventors: Takehiro Fujita, Motoyoshi Sekiya, Hidezumi Natori
  • Patent number: 7486893
    Abstract: The disclosed technology provides a dynamic interconnection system which allows to couple a pair of optical beams carrying modulation information. In accordance with the disclosed technology, two optical beams emanate from transceivers at two different locations. Each beam may not see the other beam point of origin (non-line-of-sight link), but both beams can see a third platform that contains the system of the disclosed technology. Each beam incident on the interconnection system is directed into the reverse direction of the other, so that each transceiver will detect the beam which emanated from the other transceiver. The system dynamically compensates for propagation distortions preferably using closed-loop optical devices, while preserving the information encoded on each beam.
    Type: Grant
    Filed: August 15, 2005
    Date of Patent: February 3, 2009
    Assignee: HRL Laboratories, LLC
    Inventors: David M. Pepper, Richard P. Berg
  • Publication number: 20090003839
    Abstract: A method and apparatus for compensating for channel depletion of a multi-channel signal in an optical link or optical network comprising a chain of optical amplifiers. The method comprises determining channel depletion for each amplifier from the power of the input signal to the optical amplifier and the power of the output signal from the previous amplifier. Each amplifier is then controlled to amplify the signal to a level equal to the nominal (ideal) power plus the calculated channel depletion for that amplifier.
    Type: Application
    Filed: October 6, 2006
    Publication date: January 1, 2009
    Inventors: Gianmarco Bruno, Fabio Cavaliere
  • Patent number: 7471895
    Abstract: A method is provided for locating a fault in one or more optical amplifiers operating in saturation and located along an optical transmission path. The method begins by generating a coherent optical time domain reflectometry (COTDR) trace representing a backscattered and/or reflected optical power level along the transmission path and comparing the trace to a reference trace to generate a difference trace that represents a change in gain. The change in gain is assigned to at least one of the optical amplifiers based on the difference trace. The method comprises assigning the difference trace to faults in the optical amplifiers, equating the difference trace with a linear combination of difference trace vectors each arising from a fault in a different one of the optical amplifiers, and iterating to determine a coefficient value associated with each difference trace vector. Each nonzero coefficient value denotes a fault in an optical amplifier.
    Type: Grant
    Filed: January 7, 2005
    Date of Patent: December 30, 2008
    Assignee: Red Sky Subsea, Ltd.
    Inventor: Jonathan A. Nagel
  • Patent number: 7469102
    Abstract: Various methods, systems, and apparatuses is described in which a passive-opticalnetwork includes a first multiplexer/demultiplexer, a second multiplexer/demultiplexer, a wavelength tracking component, and a transmission wavelength controller. The first multiplexer/demultiplexer is located in a first location. The second multiplexer/demultiplexer is located in a second location remote from the first location. The wavelength tracking component determines the difference between the transmission band of wavelengths of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer to provide a control signal to match the transmission band of wavelengths of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer. The transmission wavelength controller alters an operating parameter of the first multiplexer/demultiplexer based on the control signal to control the transmission band of wavelengths of the first multiplexer/demultiplexer.
    Type: Grant
    Filed: April 18, 2003
    Date of Patent: December 23, 2008
    Assignee: Novera Optics, Inc.
    Inventors: Chang-Hee Lee, Kwang-Uk Chu
  • Patent number: 7463829
    Abstract: An optical transmission apparatus comprising a first detector for detecting the power of the supervisory signal light separated from received wavelength-division multiplexed signal lights; a second detector for detecting the power of the wavelength-division multiplexed signal lights after the separation of the supervisory signal light; a gain-controlled type optical amplifier for amplifying the wavelength-division multiplexed signal lights; an optical attenuator coupled to the amplifier; and a control unit for controlling the optical amplifier and the optical attenuator so as to keep the output level of the wavelength-division multiplexed signal lights to a predetermined target value, wherein the control unit restrains automatic output level control by the optical attenuator when the supervisory signal light power fluctuates within its permissible range and fluctuations in the signal light power have deviated from its permissible range.
    Type: Grant
    Filed: December 23, 2004
    Date of Patent: December 9, 2008
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Tetsuya Uda, Kenta Noda, Yasuhiro Uchiyama, Hiroshi Masuda, Hiroyuki Nakano
  • Patent number: 7454138
    Abstract: Span information (information about conditions of a path between a node of interest and another, adjacent node connected thereto) retained in respective nodes is cumulatively transmitted from a add-drop node, which is to become a starting-point node of a certain wavelength path, toward a add-drop node, which is to become an end-point node of the wavelength path. The end-point node autonomously determines a path satisfying predetermined transmission conditions as an optimal pathway of said wavelength path, on the basis of cumulative span information transmitted over the respective plural pathways from the starting-point node to the node of interest. As a result, a load imposed on line design to be performed by a client can be mitigated, and an optimization design for each path (wavelength) matching a mesh-type optical network can be performed.
    Type: Grant
    Filed: November 17, 2005
    Date of Patent: November 18, 2008
    Assignee: Fujitsu Limited
    Inventor: Yasuko Nozu
  • Patent number: 7450298
    Abstract: An optical signal and pump light are input to a nonlinear optical medium. In the nonlinear optical medium, the optical signal is amplified with a nonlinear effect caused by the pump light. A monitor circuit monitors parametric gain in the nonlinear optical medium. A first power controller increases input power of the optical signal so that the gain reaches saturation. A second power controller controls input power of the pump light so as to obtain a desired gain.
    Type: Grant
    Filed: September 14, 2006
    Date of Patent: November 11, 2008
    Assignee: Fujitsu Limited
    Inventor: Shigeki Watanabe
  • Patent number: 7447432
    Abstract: There is provided a method of, and apparatus for, regulating radiation component (wavelength channel) power in a wavelength division multiplexed (WDM) optical communications system (10). The system (10) comprises a plurality of nodes (20) interconnected through optical waveguides (30, 40) (optical fibers). The method is characterised by: passing one or more tokens (300) around the system from node to node; adjusting nodal settings (150, 170), such as optical attenuation, applied at each node to regulate the power of WDM radiation components at the node in response to receiving one or more tokens; and repeating the method until WDM radiation component power within the system is substantially regulated.
    Type: Grant
    Filed: February 12, 2002
    Date of Patent: November 4, 2008
    Assignee: Ericsson AB
    Inventors: John Richard Fielding, Graham Ronald French
  • Patent number: 7444078
    Abstract: An optically amplified wavelength division multiplexing network has the functionality to add/drop channels at the optical add/drop multiplexing (OADM) nodes. The OADM node includes a receiver amplifier, an OADM module, and a transmitter amplifier. Once the OADM node detects a loss of signal (LOS) due to a fiber cut or network element failure upstream, the receiver amplifier is kept in operation as a noise source. The output of the receiver amplifier is immediately raised by increasing pump power to compensate for the LOS. The noise power received at the transmitter amplifier from the receiver amplifier is substantially equal to the signal power expected before LOS. The transient effect of downstream optical amplifiers is therefore completely suppressed and the inter-channel stimulated Raman scattering (SRS) induced spectrum tilt does not change. After the noise power is raised, the receiver amplifier may be shut down at a speed much slower than the speed of downstream amplifier control circuitry.
    Type: Grant
    Filed: March 17, 2004
    Date of Patent: October 28, 2008
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Joseph T. Stango, Guodong Zhang
  • Patent number: 7437083
    Abstract: A wavelength converter for binary optical signals includes an interferometer structure (110) for generating an output signal by modulating a received local signal (LS) according to the modulation of a fUrther received first input signal (IS 1). When such interferometer structures (110) are operated in a standard mode it is known in the art to control the power of the input signal such that the extinction ratio of the output signal is kept minimal. The invention also controls the power of the input signals to achieve the minimal extinction ratio when the wavelength converter and in particular the interferometer structure (110) is operated in a differential mode receiving two input signals.
    Type: Grant
    Filed: September 10, 2004
    Date of Patent: October 14, 2008
    Assignee: ALCATEL
    Inventors: Bruno Lavigne, Olivier Leclerc, Jean-Luc Moncelet, Alex Bombrun, Jean-Baptiste Pomet, Fabien Seyfert
  • Patent number: 7437070
    Abstract: In each of a plurality of submarine observation apparatus (1 to n), a branching unit (63) branches fixed-wavelength light (?1) from an incoming wavelength-multiplexed light signal. An observation signal modulating unit (64) modulates the intensity of the branched fixed-wavelength light (?1) with observation information multiplexed by an observation signal multiplex unit (61). A combining unit (65) combines light signals (?2) to (?n) passing through the branching unit (63) and the fixed-wavelength light (?1a) modulated by the observation signal modulating unit (64) into a composite light signal, and outputs it to an optical fiber (12a). Therefore, in each of the plurality of submarine observation apparatus (1 to n), there is no necessity for providing a wavelength-division-multiplexing-transmission optical transmitter which requires high wavelength stability.
    Type: Grant
    Filed: February 18, 2005
    Date of Patent: October 14, 2008
    Assignees: Mitsubishi Denki Kabushiki Kaisha, Japan Agency for Marine-Earth Science and Technology
    Inventors: Tasuku Fujieda, Hideki Goto, Kenichi Asakawa, Hitoshi Mikada, Katsuyoshi Kawaguchi
  • Patent number: 7426347
    Abstract: An apparatus for shared optical performance monitoring (OPM) is provided. A wavelength sensitive device receives light at an input port and routes it wavelength selectively to a set of output ports. To perform optical performance monitoring on the output ports, a monitoring component of each output signal is extracted, and these monitoring components are then combined. A single OPM function is then performed on the combined signal. However, with knowledge of the wavelengths that were included in each output signal, a virtual OPM function can be realized for each output port. The per port functionality can include total power per port, power per wavelength per port, variable optical attentuation, dynamic gain equalization, the latter two examples requiring feedback.
    Type: Grant
    Filed: July 15, 2005
    Date of Patent: September 16, 2008
    Assignee: JDS Uniphase Corporation
    Inventors: Alan Hnatiw, Sheldon Walklin, Thomas Ducellier