Abstract: There is provided a method for determining the in-band noise in agile multichannel Dense Wavelength Division Multiplexing (DWDM) optical systems, where the interchannel noise is not representative of the in-band noise in the optical channel. The method relies on the analysis of two observations of the same input optical signal. In the two observations, the linear relationship between the optical signal contribution and the optical noise contribution (i.e. the observed OSNR) is different, which allows the discrimination of the signal and noise contributions in the input optical signal. In a first approach, the two observations are provided by polarization analysis of the input optical signal. In a second, the input optical signal is obtained using two different integration widths.

Abstract: A tunable dispersion compensation device includes a plurality of tunable dispersion compensators coupled in series, a controller configured to control an amount of chromatic dispersion to be set in each of the plurality of tunable dispersion compensators, and a table including a correspondence relationship between an amount of chromatic dispersion and a wavelength band, for each of the plurality of tunable dispersion compensators, wherein the controller decides an amount of chromatic dispersion to be set in each of the plurality of tunable dispersion compensators, based on a total amount of chromatic dispersion desired for the plurality of tunable dispersion compensators and the correspondence relationship included in the table so that a difference between bandwidths of a first tunable dispersion compensator having the widest wavelength band and a second tunable dispersion compensator having the narrowest wavelength band, among the plurality of tunable dispersion compensators, is within a given range.

Abstract: A wavelength-division multiplexing transmission device including: a dummy light source configured to emit and quench dummy light; a monitoring unit configured to monitor an optical level relating to the received wavelength-division multiplexed light; a dummy light controller configured to control the dummy light source to emit dummy light in case where the monitoring unit determines based on the monitored optical level that the wavelength-division multiplexed light is in a condition of input interruption; and a multiplexer configured to multiplex the light of the wavelength modulated based on the transmission data and the dummy light emitted by the dummy light source, wherein the transmitter transmits wavelength-division multiplexed light generated by the multiplexer.

Abstract: An optical transport network signal (OTM) comprising at least one optical channel is received at a first network equipment. The optical transport network signal (OTM) is processed to extract optical data units (ODUk) for each optical channel (OCh). There is detection for defects during the processing. The optical data units are retransmitted within optical transport units (OTUk) towards a second network equipment. When a defect has been detected, the retransmitting comprises inserting an optical channel transport unit alarm indication signal (OTUk-AIS) in an optical channel transport unit (OTUk) containing optical channel data units (ODUk) that are affected by the detected defect.

Abstract: An optical transmission system includes an optical transmitting apparatus that includes a polarization controller configured to change a polarization state of a signal light at an operating frequency included in a frequency range at which polarization trackability is obtained on a receiving side, based on a notified monitoring result, the optical transmitting apparatus being configured to output the signal light having the changed polarization state, and an optical receiving apparatus that is provided on the receiving side and includes a monitoring control unit configured to receive the signal light having the changed polarization state and monitor transmission quality of the received signal light, the optical receiving apparatus being configured to notify the optical transmitting apparatus of the monitoring result.

Abstract: Provided are an automatic wavelength recognition apparatus and method. The automatic wavelength recognition apparatus includes: a division unit receiving a single optical signal and dividing the received optical signal into a plurality of optical signals; a plurality of filter units filtering the optical signals and having different and wavelength-dependent pass characteristics; a plurality of detection units detecting the filtered optical signals and measuring intensities of the detected optical signals; at least one comparison unit comparing outputs of any two of the detection units; and a wavelength determination unit receiving an output of the at least one comparison unit and determining a wavelength of the above single optical signal using a pre-stored look-up table.

Abstract: An optical transmission apparatus includes an interleaver configured to filter an optical carrier, a multiplexer configured to combine lights output from the interleaver to generate a composite light, a monitor configured to monitor a light intensity of the composite light, and a control circuit configured to change a grid spacing in a filter characteristic of the interleaver in a direction in which an amount of change in a light intensity of the composite light increases, on the basis of a monitoring result measured while changing a center frequency in the filter characteristic of the interleaver and to change the center frequency in the filter characteristic in a direction in which a maximum value of the light intensity increases, on the basis of the monitoring result.

Abstract: A method 10 of configuring a WDM PON comprising an OLT and a plurality of ONTs, comprising: a. identifying a plurality of OLT ports which do not have an assigned ONT assigned 12, selecting one port 12, and generating and transmitting a wavelength availability signal from the port indicative of an operating wavelength of each port 14; b. at each of a plurality of unassigned ONTs: i. receiving said availability signal and tuning a transmission wavelength of the ONT tunable filter until it transmits said signal 16; ii. generating a wavelength sequence of the operating wavelengths of the ports; iii. sequentially setting the transmission wavelength of the tunable filter at the wavelengths of the wavelength sequence 20, 28 and generating and transmitting a handshake signal at each wavelength 22 until the availability signal is no longer received 30; c. at the selected port, determining a number of handshake signals received at its operating wavelength 24.

Abstract: A system and method are provided for monitoring traffic in a network comprising a plurality of links, wherein each of the plurality of links comprises a plurality of neighboring pairs of slots. The system and method may include identifying a first usage status and a second usage status, calculating a utilization entropy value based at least on the difference between the first and second usage status, iteratively calculating a set of utilization entropy values for a portion of the network, and calculating an overall utilization entropy value for the portion of the network under analysis based at least on a statistical analysis of the set of utilization entropy values.

Abstract: Node equipment 1, having optical attenuator unit 21 for optically attenuating wavelength division multiplexing signals received and optical multiplexer/demultiplexer unit 5 for performing optical multiplexing/demultiplexing of the wavelength division multiplexing signals received from the optical attenuator unit 21 via an optical cord 11, includes: output level detecting unit 24 for detecting the optical power level of the wavelength division multiplexing signals at a pre-stage of the optical cord 11; input level detecting unit 52 for detecting the optical power level of the wavelength division multiplexing signals at a post-stage of the optical cord 11; deciding unit 25 for deciding abnormality of the optical power level loss through the optical cord 11 from the optical power levels detected by the output level detecting unit 24 and input level detecting unit 52; and control unit 26 for controlling the optical attenuation of the optical attenuator unit 21 according to the abnormality decision result by the d

Abstract: An optical channel monitor includes a demultiplexer, a plurality of paths and a processing section. The demultiplexer demultiplexes an input optical signal, which is wavelength-multiplexed, for respective multiplexed wavelengths to generate a plurality of optical signals. The plurality of paths respectively generate a plurality of digital signals indicating optical powers of the plurality of optical signals. The processing section inputs the plurality of digital signals to calculate correction values of the optical powers, which correspond to characteristics of the demultiplexer. The demultiplexer includes a filter having FMHM (Full With at Half Maximum) within a predetermined range. The predetermined range is set based on a pass center wavelength accuracy of the filter and an oscillation wavelength accuracy of a transponder which generates the input optical signal.

Abstract: A quantum key distribution system is deployed in an optical fiber network transporting classical data traffic. A source of entangled photon pairs is used to generate quantum keys. Classical data traffic is typically transported over channels in the C-band. If a pair of channels for transport of quantum data is available within the C-band, then the source of entangled photon pairs is tuned to emit in a pair of channels in the C-band. If a pair of channels for transport of quantum data is not available within the C-band, then the source of entangled photon pairs is tuned to emit in a pair of channels in a combined S-band and L-band. When a periodically-poled lithium niobate waveguide pumped with a laser is used for the source of entangled photon pairs, the output spectral properties are tuned by varying the temperature of the waveguide.

Abstract: There is provided an optical communication device includes a first transmission unit including an optical source configured to emit a reference optical pulse, an optical splitter configured to branch the reference optical pulse, and generate a plurality of optical pulses, a plurality of optical fibers configured to have different length to set various time delays for the optical pulses, and a first optical connector, and a second transmission unit including a second optical connector coupled to the first optical connector, an optical multiplexer configured to multiplex the optical pulses that have passed through optical ports of the first and second optical connectors, and generate an optical pulse train, an optical receiver configured to convert the optical pulse train into an electric pulse train, and a measuring processor configured to determine communication states of the optical ports, based on the levels of electric pulses included in the electric pulse train.

Abstract: A WDM transmission apparatus to receive or relay WDM light in a WDM transmission system, includes a measuring unit configured to measure an optical level of each channel transmitted by the WDM light; an adjusting unit configured to adjust a resolution of the measuring unit; and a processing unit configured to obtain, for each channel, optical level information which represents an optical level respectively measured with a resolution corresponding to a bit rate of a transmission signal of each channel.

Abstract: A node device includes a data pattern generator configured to generate different fixed patterns for a plurality of ports to insert the generated fixed patterns into optical signals output from a plurality of optical transmitters, an optical switch configured to switch outgoing paths of the optical signals to output the optical signals as a multiplexed signal from one of the ports, a detector configured to detect a frequency spectrum of the multiplexed optical signal, and a management part configured to monitor a peak frequency of the detected frequency spectrum to detect an erroneous optical fiber connection associated with the optical transmitters based on peak frequencies corresponding to the different fixed patterns for the respective ports.

Abstract: A method for estimating optical power in an optical channel includes determining a tunable filter full-width, FWF, by measuring a response of the tunable filter to a known signal and mapping the response to frequency. A portion of an optical channel is coupled to an input of the tunable optical filter. A peak power response, PR, and a full width tunable filter response, FWR, to the optical channel are determined by measuring a response of the tunable filter to the optical channel and mapping the response to frequency. A signal power, PS, is then calculated from the peak power response, PR, and a ratio of the full width tunable filter response, FWR, to the tunable filter full-width, FWF.

Abstract: Described herein is an optical channel monitor (100), including a plurality of input ports in the form of optical fibers (102) disposed in a vertical “port displacement” dimension. Each fiber (102) inputs a respective optical beam (103) having a plurality of individual wavelength channels. A lens (104) collimates each beam and converges the beams in the port displacement dimension to a focal plane (105). The collimated and converged beams are incident onto a rotatable micro-electromechanical system (MEMS) mirror (106), which selectively directs each optical beam onto a wavelength dispersion element in the form of a grism (108) at a predetermined angle (denoted by ?) in a horizontal “dispersion” plane. The grism (108) spatially separates, in the dispersion plane, the wavelength channels contained within each optical beam (103) by diffraction. The angle at which each channel is diffracted is controlled by the angle ?.

Abstract: An optical packet switching apparatus includes an optical packet switching apparatus, an optical transmitting apparatus, and an optical packet receiving apparatus. The optical packet transmitting apparatus includes a packet generator for generating a packet signal by adding the routing information to a received client signal, a BIP adding unit for adding BIP to the generated packet signal, and an electrical-to-optical converter for converting the packet signal, to which the BIP has been added, into an optical packet signal so as to be sent out. The optical packet receiving apparatus includes an electrical-to-optical converter for converting the received optical packet signal into an electrical packet signal, and a BIP comparison unit for detecting the error occurrence in the packet signal, based on the BIP added to the packet signal.

Abstract: The present document relates to a method and apparatus in optical transmission systems for the estimation of the carrier phase and the degree of non-linear distortions incurred in an optical transmission channel. A plurality of signal samples are provided at succeeding time instances such that the plurality of signal samples: is associated with a modulation scheme and a carrier phase; has been transmitted over the optical transmission channel; comprises a plurality of signal phases, respectively; comprises a plurality of data phases and a plurality of residual phases, respectively; and the plurality of residual phases is associated with the carrier phase. The method comprises further canceling the plurality of data phases from the plurality of signal phases by taking into account the modulation scheme; thereby yielding the plurality of residual phases; and determining a set of autocorrelation values of the plurality of residual phases for a set of lag values, respectively.

Abstract: The optical channel monitor includes a polarization adjuster, a wavelength divider, a polarization divider, a first intensity detector, and a second intensity detector. The polarization adjuster adjusts the plane of polarization of a first optical signal to a first direction and the plane of polarization of a second optical signal to a second direction. The wavelength divider divides each of the optical signals multiplexed on the first and second optical signals, in accordance with the wavelengths. The polarization divider divides each of the divided optical signals, based on the direction of the plane of polarization. The first intensity detector receives an optical signal whose direction of the plane of polarization is the first direction among the divided optical signals. The second intensity detector receives an optical signal whose direction of the plane of polarization is the second direction.

Abstract: A system and method is disclosed that allows for the monitoring, analyzing and reporting on performance, availability and quality of optical network paths. The correlation of PM parameter metrics to client connections, coupled with threshold-based alarm generation provides a proactive and predictive management, reporting and analyzing of the health and effectiveness of individual path connections to alert Operational Support (OS) staff and/or customers to signal degradation and impending Network Element (NE) failures. The system and method performs in real-time processing intervals required for alarm surveillance in a telecommunications network.

Abstract: The path selection and wavelength assignment to a selected path are performed by mapping the wavelength reach to the demand distribution (agile reach) resulting in a 50-60% increase in the network reach. The network reach is further increased (about 2.2 times) when on-line measured performance data are used for path selection and wavelength assignment. The connections may be engineered/upgraded individually, by optimizing the parameters of the entire path or of a regenerator section of the respective path. The upgrades include changing the wavelength, adjusting the parameters of the regenerator section, controlling the launch powers, mapping a certain transmitter and/or receiver to the respective wavelength, selecting the wavelengths on a certain link so as to reduce cross-talk, increasing wavelength spacing, etc.

Abstract: The invention relates to a network comprising at least one host device having an interface card connected to a backplane of said host device, wherein said interface card comprises at least one cage for receiving a pluggable module which performs a traffic management of data transported via at least one optical fiber connected to said pluggable module.

Abstract: Methods and apparatus for varying the transmission rate of a signal transmitted within a dense wavelength division multiplexing (DWDM) system or network are disclosed. According to one aspect of the present invention, a method includes obtaining a first signal and determining a transmission rate associated with the first. If it is determined that the transmission rate is a first rate, the method includes processing the first signal as having a first transmission format and the first rate. Alternatively, it is determined that the transmission rate is not the first rate and is a second rate, the method includes processing the first signal as having a second transmission format and a second rate.

Abstract: In a network design apparatus, a full channel evaluator determines whether all wavelength channels for main signals can deliver the main signals of an existing optical network. When it is found that one or more wavelength channels cannot deliver main signals, a chromatic dispersion evaluator determines whether there are a specified number of wavelength channels that satisfy a specified chromatic dispersion condition. An optical signal-to-noise ratio (SNR) evaluator extracts a specified number of wavelength channels out of those satisfying the chromatic dispersion condition in descending order of optical SNRs thereof, and determines whether the extracted wavelength channels satisfy a specified optical SNR condition.

Abstract: A storage device stores information regarding a channel from which an optical transmission apparatus at a subsequent stage drops a signal light. A processor determines that switching from second channel transmission using a larger number of channels than a first number of channels to first channel transmission is performed, and controls an attenuation amount, when performing the first channel transmission using the first number of channels, by referring to the storage device according to the determination and making the attenuation amount in a no-signal channel larger than a determine value if the no-signal channel whose wavelength is within a determined range from the wavelength of the signal light channel for the first channel transmission is a channel from which the optical transmission apparatus at the subsequent stage drops a signal light, so as to transmit an amplified spontaneous emission light along the no-signal channel.

Abstract: According to an aspect of an embodiment, an apparatus includes an optical branching unit for branching an input signal light in four directions, a polarization component extraction unit extracting four polarization components having mutually different polarization parameters from lights branched in four directions by the optical branching unit, and a determination unit determining input/non-input of the signal light based on the four polarization components extracted by the polarization component extraction unit.

Abstract: The path selection and wavelength assignment to a selected path are performed by mapping the wavelength reach to the demand distribution (agile reach) resulting in a 50-60% increase in the network reach. The network reach is further increased (about 2.2 times) when on-line measured performance data are used for path selection and wavelength assignment. The connections may be engineered/upgraded individually, by optimizing the parameters of the entire path or of a regenerator section of the respective path. The upgrades include changing the wavelength, adjusting the parameters of the regenerator section, controlling the launch powers, mapping a certain transmitter and/or receiver to the respective wavelength, selecting the wavelengths on a certain link so as to reduce cross-talk, increasing wavelength spacing, etc.

Abstract: An optical network (10) comprising an optical network element (12) comprising a first optical transmitter (14), a first controller (16), an optical receiver (18), a second optical transmitter (22), a second controller (24) and optical receiver apparatus (26). Said first controller is arranged to control said first optical transmitter to generate and transmit a first optical signal in response no second optical signal being detected. Said first controller is arranged to iteratively generate and transmit said first optical signal at different wavelengths of a plurality of wavelengths until said second optical signal is detected, and is further arranged to subsequently maintain generation and transmission of said first optical signal at said wavelength at which said second optical signal is detected. Said second controller is arranged to control said second optical transmitter to generate and transmit said second optical signal following detection of said first optical signal by said optical receiver apparatus.

Abstract: In one exemplary embodiment, a method comprises transmitting an optical signal via the optical line, measuring a relative change in spectral intensity of the optical signal near a clock frequency (or half of that frequency) while varying a polarization of the optical signal between a first state of polarization and a second state of polarization, and using the relative change in spectral intensity of the optical signal to determine and correct the DGD of the optical line. Another method comprises splitting an optical signal traveling through the optical line into a first and second portions having a first and second principal states of polarization of the optical line, converting the first and second portions into a first and second electrical signals, delaying the second electrical signal to create a delayed electrical signal that compensates for a DGD of the optical line, and combining the delayed electrical signal with the first electrical signal to produce a fixed output electrical signal.

Abstract: An optical communication system includes logic to communicate using optical channels set outside a fiber zero dispersion zone, and having channel spacing that decreases with increasing distance from the fiber zero dispersion zone.

Abstract: An embodiment of the invention is an optical node configured to transmit/receive a wavelength-division-multiplexed signal. An optical monitoring unit monitors power levels of the wavelength-division-multiplexed signal on a wavelength-by-wavelength basis to acquire wavelength-by-wavelength power level values of the optical signals. A comparison arithmetic unit performs a comparison between each of the acquired wavelength-by-wavelength power level values of the optical signals, and a predetermined upper limit value and a predetermined lower limit value. A target value calculation unit determines target values of power levels at wavelengths whose acquired power level values exceed the upper limit value to be values between a center value and the upper limit value, and determines target values of power levels at wavelengths whose acquired power level values fall below the lower limit value to be values between the center value and the lower limit value.

Abstract: A method and a device are provided for processing data in an optical network. The method includes the steps of events of a login scan are recorded by a first optical network element; the events are conveyed to a second optical network element; and the events are processed by the second optical network element. A communication system is described that includes the device.

Abstract: Described herein are systems and methods for a field-configurable optical network terminal (ONT) device at a subscriber to provide one or more communication services to the subscriber. The field-configurable ONT device is of a modular design operable for the insertion of additional communication modules or removal of existing communication modules from the ONT device for scaling the device to increased or decreased communication capacity as desired.

Abstract: There is provided an abnormal light cut-off system in which even when a high power light is inputted from an optical fiber connected to a user side apparatus by a malicious user or an accident, a trouble rate is low, the abnormal light is cut off at high sensitivity, and security is high.

Abstract: A method and apparatus for implementing optical network quality using bit error rate and chromatic dispersion. According to one embodiment of the invention, a method includes the provision of quality of service in a wavelength division multiplexing optical network that supports a plurality of bit rates. As part of this method, the cumulative noise and cumulative chromatic dispersion for each available path as a whole is determined, where an available path is a series of two or more nodes each connected by an optical link on which a set of wavelengths is available for establishing a lightpath. In addition, different grades of path quality are distinguished based on bit error rate (BER), where BER is based on cumulative noise and bit rate. Furthermore, a minimum path quality is required based on chromatic dispersion decibel penalty, where chromatic dispersion decibel penalty is based on cumulative chromatic dispersion and bit rate.

Abstract: An optical transmission apparatus includes an optical transmitter that outputs a signal light corresponding to a wavelength of a WDM light, a multiplexer that multiplexes lights input to the plurality of input ports, and that outputs a light generated through the multiplexing from the one or more output port, an optical amplifier that amplifies the light output from the multiplexer; and an amplified spontaneous emission (ASE) transmitter that inputs branching off part of the light output from the optical amplifier by a splitter and multiplexes, with the signal light, ASE in a wavelength band corresponding to an unused wavelength adjacent to the signal light included in the branched-off light.

Abstract: A PON station side apparatus is provided with a selection section and a receiving section. For multiple data transferred from multiple PON terminal apparatuses that transmit data at different communication speeds in time division multiplexing, the selection section selects any of the multiple receiving circuits to be a receiving circuit for a receiving destination at which data is received on the basis of the transmission time zones for the data. The receiving section switches the receiving circuit selected by the selection section among the multiple receiving circuits to be the receiving circuit for the destination at which data is received of the data and receives the data through the switched receiving circuit.

Abstract: A method of collecting data from an optical channel monitor for monitoring the power of a wavelength-division multiplexed light signal at each wavelength is disclosed. The total light power is analog-to-digital converted by an A/D converter. The data of the total light power which has been analog-to-digital converted is compared with a reference light power by a comparator for each conversion, and when the difference between the total light power and the reference light power exceeds a predetermined threshold, a power fluctuation flag is turned ON. After the comparison, the above process of the analog-to-digital conversion and the comparison is iterated until the optical channel monitor completes the data collection for each wavelength. Thereafter, the processor determines whether the power fluctuation flag is ON or not. When the power fluctuation flag is ON, the processor discards the currently collected data and maintains the data which were collected immediately before.

Abstract: The invention relates in general to a method, an apparatus and a unit for operating a Wavelength Division Multiplexing Access Network 25, and in particular to unbundling wavelengths in the network 25. Embodiments of the invention disclose monitoring a plurality of wavelengths of the Wavelength Division Multiplexing Access Network 25 to determine at least one available wavelength that is free for use. The transmitter then automatically transmits data to at least one user device 22 via at least one available wavelength.

Abstract: A wavelength selective switch includes an input port and an output port, a wavelength demultiplexer that demultiplexes wavelength-multiplexed signal light into wavelengths in different optical paths, an optical-path controller that controls an array that has a plurality of switch elements, the plurality of switch elements switching all or a part of the wavelengths to be coupled from the input port to the output port, and an actuator driver that shifts the plurality of switch elements, based on a deviation of a center wavelength of a pass band from a reference wavelength.

Abstract: To, even when a transmission wavelength varies in each ONU and an optical amplifier gain depends on the wavelength in an OLT equipped with an optical amplifier, prevent the optical amplifier gain from varying in every ONU and thus prevent deterioration of a dynamic range. The OLT estimates a transmission wavelength of each ONU at the time of ONU registration, and retains a correspondence between an ONU identifier and the transmission wavelength. Moreover, for every burst, an injection current to the optical amplifier is adjusted based on a wavelength and optical amplifier characteristic database.

Abstract: A method and an optical component for data processing in an optical network are provided, wherein two sets of wavelengths are allocated; wherein at least one set of wavelengths is monitored; and wherein a collision between the two sets of wavelengths is avoided or compensated by adjusting at least one laser of an optical component. Furthermore, an optical communication system is suggested including said optical component.

Abstract: A method and apparatus of managing remote third party OTN & WDM transceiver equipment using the same fibers used for end user data exchange is described. A network device collects management instructions for the OTN & WDM transceiver equipment, assembles this management information into the overhead of a data frame and transmits on an optical link directly coupled to the network device. The WDM transceiver function converts the optical signal to an electrical one and the OTN function extracts the management instructions from the OTN overhead. A processor associated with the OTN framer function acts on that information. The management instructions includes the instruction to periodically and continuously, load certain performance, alarm or informational data into its OTN overhead and transmit that to a similar transceiver at the remote end of the communications link.

Abstract: Optical transmission equipment includes: a first optical amplifier to amplify an input optical signal; a second optical amplifier provided at an output side of the first optical amplifier; an optical module having a first relay port to receive an optical signal from the first optical amplifier, a second relay port to output an optical signal to the second optical amplifier, an optical device provided between the first relay port and the second relay port, and a first output port optically couplable to the optical device; and a second output port to output the optical signal amplified by the second optical amplifier.

Abstract: A testing input module for testing an in-service WDM system is provided. The testing input module includes a first light source configured to emit a first light signal to one or more empty channels of the in-service WDM system; and a tunable second light source configured to emit a second light signal to test the one or more empty channels. The testing input module also includes a first switch module configured to: receive from the first light source and output the first light signal during a first time interval; and receive from the second light source and output the second light signal during a second time interval. The second time interval is a duration wherein a channel power monitoring function of the in-service WDM system is not triggered.

Abstract: Methods and apparatus for efficiently utilizing an optical control plane distinct from an electronic control plane to facilitate the setup of paths in a dense wave division multiplexing network are disclosed. According to one aspect of the present invention, a method includes receiving a probe arranged determine the optical feasibility of a first path, and determining a probability of success associated with the probe. The probability of success indicates a likelihood that the probe will be successfully routed on the first path to the destination, and is associated with a particular wavelength. A second path on which to route the probe is dynamically identified if the probability indicates a low likelihood of successful routing on the first path. Finally, the method includes determining if a notification associated with the probe has been received, and altering the probability of success based on the notification if the notification has been received.

Abstract: An optical transmission device includes an extractor that extracts respective optical signals from optical signals multiplexed from a plurality of optical signals of different wavelengths, a detector that detects wavelengths of the extracted respective optical signals, a storage that stores the wavelengths of the detected respective optical signals, and a processor that is operative to derive trends in wavelength variation of the respective optical signals based on the detected respective optical signals and the respective optical signals stored in the storage, and determines that either one or both of the extractor and the detector cause the wavelengths to be varied when the trends in wavelength variation of two or more wavelengths are the same.

Abstract: An optical switching device includes a optical add/drop multiplexer that at least adds an optical signal into and/or drops an optical signal from wavelength division multiplexed light that is wavelength division multiplexed optical signals; a plurality of amplifiers that are disposed on optical paths included in the optical add/drop multiplexer and that can use supplied pump light to amplify the optical signals; an optical source that generates the pump light; and an optical switch that supplies the generated pump light to any one of the amplifiers.

Abstract: A pre-emphasis control method includes calculating an average value of transmission characteristics based on transmission characteristics of a plurality of light beams received by the receiver, and determining that, among signals of the plurality of light beams, a wavelength with a deviation from the average value is a wavelength at which control is to be performed, determining that the wavelength at which control is to be performed and a wavelength adjacent thereto are a group of wavelengths at which control is to be performed, obtaining an average of transmission characteristics of the group of wavelengths at which control is to be performed, and changing a light intensity output from each transmitter that transmits a group of wavelengths at which control is to be performed based on a difference between averaged transmission characteristics and respective transmission characteristics of the group of wavelengths at which control is to be performed.