Abstract: An optical transmission apparatus includes a wavelength multiplexing unit that performs wavelength multiplexing with respect to dummy light for each channel of WDM and dummy light for each sub-band including the channels in plural; and a selecting unit that measures for each sub-band and corresponding to intensity of the channel-specific dummy light, transmission characteristics at a reception end, and according to measurement results, selects for each of the sub-bands, any one among the channel-specific dummy light and the sub-band-specific dummy light. The wavelength multiplexing unit wavelength multiplexes any of the channel-specific dummy light selected for each of the sub-bands by the selecting unit.

Abstract: The system-level control of a repeatered optical communications system. In a repeatered optical communications system, two terminals are optically coupled via an optical communications span having one or more repeaters. One of the terminals may perform the control by monitoring quality metrics of optical signals received over the communication span. Based on this monitoring, certain adjustments are determined to be performed, and the repeater controllers of the respective optical repeaters are instructed to perform the adjustments. In some case, the optical repeater adjustments cannot be made without impacting the performance of the optical signals traveling in the opposite direction. In that case, the system-level control uses monitored quality metrics from both terminals to determine the adjustments to be made. The system level adjustment may be automated by software or the like thereby making optimization of the optical communications span easier.

Abstract: An example embodiment includes an optical transmission device. The optical transmission device includes an optical source, a collimator lens, and an optical monitor. The optical source is configured to transmit a channel of light. The collimator lens is configured to reflect a portion of the channel of light. The optical monitor is arranged to receive at least a first portion of the reflected channel of light directly from the collimator lens, and is configured to communicate a gross electrical signal representative of received light including the first portion of the reflected channel of light.

Abstract: A light channel monitor includes an optical separating section configured to separate a wavelength multiplexed optical signal into optical signals for channels and monitors configured to measure intensities of the optical signals for the channels. A processing section is configured to correct the measured intensities of the optical signals based on a wavelength transmission characteristic of the optical separating section to calculate the wavelength multiplexed optical signal before the separation.

Abstract: A method of monitoring a differential group delay (DGD) of an optical communications signal having a polarisation multiplexed modulation format is described. The method includes the operations of receiving a signal and performing analogue to digital conversion of the signal to generate a digitised signal corresponding to one polarisation of the signal and to generate another digitised signal corresponding to another polarisation of the signal, and applying a polarisation mode dispersion(PMD) compensation to each of the digitised signals. The method further includes the operations of obtaining an indication of the channel transfer function of the optical communications signal, determining a DGD in dependence on the indication of the channel transfer function, determining a delay between the PMD compensated digitised signals, subtracting the delay from the DGD to obtain a corrected DGD, and generating and transmitting a monitoring signal with an indication of the corrected DGD.

Abstract: Optical network protection devices and protection methods including: a working line; a protection line; a determination module configured to determine the protection type of optical network; a first judgment module configured to judge whether the working line is normal according to performance parameter values of service signal in the working line and switching conditions configured for multiplexing section protection when the protection type of optical network is the multiplexing section protection; a second judgment module, configured to judge whether the working line is normal according to performance parameter values of service signal in the working line and switching conditions configured for channel section protection when the protection type of optical network is the channel section protection; a switching module, configured to take the service signal in the protection line as an output signal when working line is abnormal.

Abstract: A display method and apparatus provides an easy to interpret presentation of multiple channel data, in the form of columns where the height of the column represents the relative measurement. A threshold line provides an indication of whether the measurement is above or below the threshold. Greater detail and numeric measurement values can be displayed for individual channels while the multiple channel display is in view.

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 wavelength sensing lighting system may include a light source, a sensor and a controller. One or more light sources and sensors may be included in an array. The light source may emit an illuminating light and the sensor may sense an environmental light. The illuminating light may include data light. The lighting system may include a plurality of nodes connected in a network. The nodes may communicate by emitting and receiving the data light, which may be analyzed by the controller. The light source and the sensor may be provided by a light emitting semiconductor device that is capable of emitting illuminating light and receiving environmental light. A conversion material may convert the wavelength of a source light into a converted light. The conversion material may increase the wavelength range of light emittable and detectable by the lighting system.

Abstract: Tuning an optical network unit (ONU) to an appropriate communication wavelength may be performed by initiating an activation procedure responsive to receiving a wavelength configuration message, and identifying an instruction in the wavelength configuration message to modify a present wavelength used by the network unit to a different wavelength. The process may also provide assigning an optical network unit identifier (ONU-ID) to the network unit, modifying the present wavelength to the different wavelength, and transmitting subsequent data messages from the network unit at the different wavelength.

Abstract: Provided is a wavelength division multiplexing (WDM) optical transmitting apparatus including first to n-th optical transmitters configured to output first to n-th optical signals having different wavelengths, respectively; a wavelength multiplexer configured to multiplex the first to n-th optical signals and generate an output optical signal; a tap coupler configured to receive the output optical signal and generate a controlling optical signal based on some of the output optical signal; a controlling photodetector configured to receive the controlling optical signal and output an optical current based on the controlling optical signal; and a controller configured to control each of the first to n-th optical transmitters based on the optical current, wherein the controller comprises a look-up table, sequentially detects driving conditions for the first to n-th optical transmitters, stores the detected driving conditions in the look-up table, and controls the first to n-th optical transmitters based on the de

Abstract: Each optical transmission device includes a detecting unit, a notifying unit, and a control unit. The detecting unit detects a value of the optical power of each of multiple wavelengths. The notifying unit notifies an optical transmission device at the upstream side of a control frame that includes the value and that includes information that indicates the execution state of the optical power control. The control unit calculates the adjustment level on the basis of the optical power of each of the wavelengths detected by the detecting unit. Furthermore, when the information included in the control frame sent from an optical transmission device at the downstream side indicates that the optical power control is being stopped, the control unit calculates the adjustment level on the basis of the value included in the control frame and executes optical power control by setting the calculated adjustment level to the optical device.

Abstract: A method includes generating a test signal and modulating the test signal. The method may also include transmitting the test signal on an optical path, where the optical path may include a number of add-drop multiplexer devices and amplifiers. The method may also include receiving the test signal at a destination device and converting the received test signal into an electrical signal. The method may further include identifying a portion of the electrical signal that is associated with the modulated test signal.

Abstract: Techniques are presented herein to setup a wavelength on a path from a source node to a destination node. Cross-talk margin information already computed for one or more installed wavelengths is obtained between the source node and destination node. A total margin as a function of the cross-talk margin information is computed. A determination is then made as to whether to perform non-linear impairment validation of the wavelength based on the total margin. These techniques may be generalized to account for coherent and non-coherent portions of a network.

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: Exemplary systems, devices, and methods for evaluating a link status of a fiber-optic communication system are disclosed. An exemplary transceiver device includes a transmitter configured to transmit an optical signal having a first wavelength to an additional transceiver device by way of a single optical fiber, a receiver configured to receive an optical signal having a second wavelength from the additional transceiver device by way of the single optical fiber, and a link status facility communicatively coupled to the transmitter and the receiver and configured to provide one or more visual indications of a link status between the transceiver device and the additional transceiver device. Corresponding systems, devices, and methods are also disclosed.

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 wavelength selective optical switch device includes an incidence and exit part where a signal beam made of light of a multiplicity of wavelengths enters and a signal beam of a selected wavelength exits, a wavelength dispersion element that spatially disperses a signal beam according to the wavelength thereof and multiplexes reflected light, a condensing element that condenses the light dispersed by the wavelength dispersion element onto a two-dimensional plane, and a wavelength selection element that uses a multilevel optical phased array arranged in a position to receive incident light developed on an xy-plane made of an x-axis direction and a y-axis direction perpendicular thereto developed according to a wavelength, having a multiplicity of pixels arrayed in a lattice on the xy-plane, and that cyclically changes the phase shift amount in the y-axis direction to a sawtooth wave pattern for each pixel on the x-axis.

Abstract: The present invention enables to prevent transmission characteristics from deteriorating due to the nonlinear effect in the transmission path caused by an increase in the channel power when a cable disconnection occurs.

Abstract: A method of determining a power correction factor for an optical power of an optical channel of a wavelength division multiplexed communications network. The method comprises configuring an optical source of the communications network to generate an unmodulated optical carrier signal for the optical channel. The method further comprises determining the optical power of the unmodulated optical carrier signal (PHIGH). The method further comprises configuring the optical source to apply a test modulation pattern to the optical carrier signal, to generate a modulated optical carrier signal. The method further comprises determining the optical power of the modulated optical carrier signal (PMOD). The method further comprises determining a power correction factor for the optical channel by determining the difference between the optical powers of the unmodulated optical carrier signal and the modulated optical carrier signal.

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 (e.g. 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: Example embodiments presented herein are directed towards an optical testing node, and method therein, for establishing transmission parameters for optical communications in an iterative manner. The establishment of the transmission parameters may comprise adjusting various parameters such as a modulation scheme, a light path length, and/or a spectral width.

Abstract: The TWDM-PON system includes a service provider equipment configured to comprise a plurality of Optical Line Terminals (OLTs), wherein each OLT provides a service in a TWDM scheme; a subscriber equipment configured to comprise a plurality of an Optical Network Units (ONUs), wherein each of the plurality of ONUs utilizes a service provided from one of the plurality of OLTs using an optical signal of an arbitrary wavelength; an Optical Division Network (ODN) configured to transmit multi-wavelength downstream optical signals and multi-wavelength upstream optical signals; and a Reach Extender (RE) configured to comprise at least one of a downstream optical amplifier and an upstream optical amplifier, wherein the downstream optical amplifier is configured to amplify the multi-wavelength optical signals simultaneously, and the upstream optical amplifier is configured to amplify the multi-wavelength optical signals simultaneously.

Abstract: Disclosed is an optical line terminal for monitoring and controlling upstream and downstream optical signals, and more particularly, to an optical line terminal for monitoring and controlling upstream and downstream optical signals, which adds different low frequency monitoring signals to upstream and downstream wavelength division multiplexing optical signals in a bidirectional wavelength division multiplexing (WDM) optical network and senses and detects low frequency components of upstream and downstream optical signals to unite, monitor, and control optical outputs and wavelengths of the upstream and downstream wavelength division multiplexing optical signals into a single system.

Abstract: A system to provide carrier frequency control in an optical network includes a first network element monitoring performance information and a second network element coupled to the first network element by the optical network. The second network element receives performance information from the first network element using an administration channel bandwidth, and modifies a carrier frequency associated with the second network element based on the performance information such that the carrier frequency is aligned to a center of a signal channel bandwidth. A method of providing carrier frequency control includes transmitting performance information by the first network element to the second network element using an administration channel bandwidth, and modifying the carrier frequency by the second network element based on the performance information such that the carrier frequency is aligned to the center of the signal channel bandwidth.

Abstract: An apparatus comprising an optical transmitter, a coarse tuner coupled to the optical transmitter and having a first tuning range, a fine tuner coupled to the optical transmitter and having a second tuning range smaller than and within the first tuning range, a wavelength division demultiplexer coupled to the optical transmitter and to a plurality of optical fibers, and a detector coupled to the optical transmitter and the wavelength division demultiplexer.

Abstract: A passive optical network (PON) component comprising a processor coupled to a plurality of receivers, the processor configured to monitor a plurality of drifting laser wavelengths and cause the drifting laser wavelengths to be tuned to a plurality of pass-bands. Also disclosed is an optical network unit (ONU) comprising a receiver, a transmitter coupled to the receiver, and a partially-tunable laser coupled to the transmitter and having a drifting laser wavelength, wherein the drifting laser wavelength is periodically tuned to one of a plurality of pass-bands. Included is a method comprising monitoring a plurality of drifting laser wavelengths associated with a plurality of pass-bands, and reconfiguring a plurality of time division multiple access (TDMA) timeslots when one of the drifting laser wavelengths migrates from one pass-band to another pass-band.

Abstract: A tunable optical filter is configured to take point measurements at a few optical frequencies per frequency channel of a DWDM optical network. The measurement frequencies are shifted by pre-determined amounts relative to the optical frequency channel being characterized. Since the spectral shape of the tunable optical filter is known, the center optical frequency, the modulation bandwidth, and the total optical power of the channel can be obtained from as few as three optical measurements. The center optical frequency and the total optical power can be continuously monitored by providing a tunable filter stage coupled to an interleaver stage, and computing a ratio and a weighted sum the optical signals at the two outputs of the interleaver stage.

Abstract: An amplifier receives an optical signal including a number of labeled channels via a fiber. The amplifier determines a count of the labeled channels and a spectral distribution of the labeled channels. The amplifier adjusts a parameter of the amplifier based on the count of the labeled channels and the spectral distribution of the labeled channels. The amplifier amplifies the optical signal at an adjusted output gain resulting from adjusting the parameter of the amplifier.

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: An optical transmission system includes: an optical transmission device that has a plurality of optical transmitters configured to output at least one different wavelength and a multiplexer configured to multiplex wavelength lights output by the plurality of optical transmitters and output a multiplexed wavelength light; and a detection unit configured to detect each wavelength light that is branched before being fed into the multiplexer by sweeping an objective wavelength for detection, wherein, in a single sweeping, the detection unit selects and detects two or more wavelength lights with a wavelength interval that is wider than a wavelength interval of an output light of the multiplexer.

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: The present disclosure describes a reconfigurable optical add-drop multiplexer. The reconfigurable optical add-drop multiplexer includes a first optical equalizer to precompensate a received optical signal for optical filtering effects to produce a first compensated optical signal. A first interleaver, coupled to the first optical equalizer, separates the first compensated optical signal into an odd optical signal and an even optical signal. A plurality of wavelength selective switches processes the odd optical signal and the even optical signal. A second interleaver, combines the odd optical signal and the even optical signal to produce a combined optical signal. A second optical equalizer, coupled to the second interleaver, postcompensates the combined optical signal for optical filtering effects to produce an output optical signal.

Abstract: Optical service channel (OSC) systems and methods over high loss links are described utilizing redundant telemetry channels. A first telemetry channel provides a low bandwidth communication channel used when Raman amplification is unavailable on a high loss link for supporting a subset of operations, administration, maintenance, and provisioning (OAM&P) communication. A second telemetry channel provides a high bandwidth communication channel for when Raman amplification is available to support full OAM&P communication. The first and second telemetry operate cooperatively ensuring nodal OAM&P communication over high loss links (e.g., 50 dB) regardless of operational status of Raman amplification.

Abstract: A method for blocking estimation to evaluate connection blocking in flexible optical wavelength division multiplexing WDM networks includes a novel Markovian model to analyze the steady state probabilities and connection blocking probability along a fiber in FWDM networks and finding the state dependent arrival rate for each type of line rate on a fiber

Abstract: A first transmission apparatus and a second transmission apparatus recognize the working path and the back-up path group from communication paths between the two apparatuses. The first transmission apparatus selects a measurement path from the back-up path group and transmits a test signal via the measurement path to the second transmission apparatus. The second transmission apparatus uses the test signal to measure communication quality, records the measurement data, and transmits a test signal including the measurement data via the measurement path to the first transmission apparatus. The first transmission apparatus records the measurement data included in the test signal from the second transmission apparatus, uses the test signal to measure communication quality, and records that measurement data.

Abstract: An optical transmission apparatus includes a reception part for receiving a wavelength division multiplexed (WDM) signal reached via optical amplifiers; a measuring part for measuring an optical power level of each wavelength of the WDM signal received by the reception part; a determination part for determining whether an amount of tilt of the WDM signal calculated based on measurement results of the measuring part is suitable or not; an operation part for calculating the tilt correction amount to be applied to tilt correction processing performed by the optical amplifiers if the amount of tilt of the WDM signal is not suitable; and a notification part for notifying the optical amplifiers of the tilt correction amount.

Abstract: A node for a communications network has a converter for digitizing at a receiver clock rate a received optical signal received over an optical link from an optical transmitter at a source node, a framer for detecting frames and a forward error correction part for correcting errors in the payload of the frame. An error rate in the received payload part is monitored and a processor sends, according to the monitored error rate, a request to the optical transmitter to adapt a length of the transmitted forward error correction part and to adapt a clock rate of the transmission of the frame if FEC length is reduced or FEC is disabled. This can enable power saving, when less FEC information is being sent.

Abstract: An apparatus comprising a plurality of optical transmitters coupled to a fiber, a signal generator coupled to the optical transmitters and configured to provide a single pilot tone to the optical transmitters, and a processor positioned within a feedback loop between the fiber and the optical transmitters, the processor configured to adjust a wavelength for each of the optical transmitters to lock the wavelengths. An apparatus comprising at least one processor configured to implement a method comprising receiving an optical signal comprising a pilot tone, detecting an amplitude and a phase of the pilot tone, calculating a quadrature term using the amplitude and the phase, and wavelength locking the optical signal using the quadrature term.

Abstract: A method and system for protecting integrated optoelectronic devices are disclosed. The method includes (1) providing standby light source links of fixed wavelength and their corresponding standby data channel in a transmitting-end integrated optoelectronic device; (2) detecting whether there is failure in each active light source link in the transmitting-end integrated optoelectronic device; and (3) selecting a standby light source link having a fixed wavelength and its corresponding standby data channel for accomplishing service transmission of failed active light source link and its corresponding active data channel when detecting failure of an active light source link. The system includes a transmitting-end integrated optoelectronic device and a receiving-end integrated optoelectronic device.

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 signal processing of data comprised of at least one WDM channel transported via at least one optical fiber connected to said pluggable module in the optical domain.

Abstract: A clock at a first network element that is connected to a second network element over first and second optical links that are physically distinct from each other is aligned using optical timing signals having different wavelengths. Transit delays between the first and second network elements may be determined using the same optical timing signals.

Abstract: The present invention relates to a passive wavelength division multiplexing device for automatic wavelength locking and a system thereof including an optical multiplexer, an optical filter, an integrated optical receiver monitor, and a tunable optical transmitter. Through wavelength locking that adjusts a wavelength of an optical signal, which changes according to an external environment such as a temperature change, into a wavelength of an optical signal having the maximum optical intensity, communication quality may be maximized by securing a stable communication channel, a locking time and a communication channel setting time may be reduced, and more robust locking may be guaranteed.

Abstract: An optical signal-to-noise ratio monitor includes a demodulator comprising an input that receives at least a portion of a phase modulated optical signal. The monitor also includes a delay interferometer with a periodic phase control that sweeps a differential delay of one arm of the interferometer through a plurality of differential optical phase shifts. The demodulator converts phase modulated optical signals to intensity modulated optical signals. A tunable optical filter continuously scans a transmission wavelength over a desired wavelength range in a time that allows more than one wavelength to be transmitted through an output of the tunable filter for each of the plurality of differential optical phase shifts. An optical detector detects the filtered optical signal and generates a corresponding electrical demodulation signal at an output. A processor determines an optical signal-to-noise ratio for the more than one wavelength of the optical signal.

Abstract: An apparatus comprising an optical transmitter, a coarse tuner coupled to the optical transmitter and having a first tuning range, a fine tuner coupled to the optical transmitter and having a second tuning range smaller than and within the first tuning range, a wavelength division demultiplexer coupled to the optical transmitter and to a plurality of optical fibers, and a detector coupled to the optical transmitter and the wavelength division demultiplexer. A network component comprising at least one processor configured to implement a method comprising detecting an Optical Time Domain Reflectometry (OTDR) signal spectrum that has a modulated pattern, and detecting a reflected OTDR signal spectrum that has a shifted modulated pattern comprising a frequency shift with respect to the OTDR signal spectrum and a time shift proportional to the frequency shift.

Abstract: A span loss monitoring system includes a supervisory signal sending apparatus with a output level monitoring section, a time stamp generation section, and a supervisory signal generation section that generates a supervisory signal including a pair of the output level measurement hour and the output level. The span loss monitoring system also includes a supervisory signal receiving apparatus with an input level monitoring section, a supervisory signal termination section and a span loss calculation section.

Abstract: A monitoring system which enables monitoring of a transponder accommodated in an optical path in a transmission node and a node according to their operation conditions is provided. The monitoring system comprises a monitor control management unit connected to at least one of ports of wavelength selective switches which monitors an inspection signal or an operation signal, and a control unit which controls the wavelength selective switch so as to enable monitoring by the monitor control management unit.

Abstract: An optical amplifier using the evanescent light to control the optical output level is provided. The optical amplifier includes: a waveguide path transmitting an optical signal; an optical amplification unit formed on the waveguide path and amplifying the optical signal by an excitation light; an irradiation unit irradiating the excitation light to the optical amplification unit; an optical detection unit generating an electric signal which corresponds to a detected light; a branching unit branching an evanescent light being the optical signal outputted from the optical amplification unit and leaked outside the waveguide path, and focusing the evanescent light on the optical detection unit; a wavelength detection unit detecting a wavelength multiplicity of the optical signal based on the detected evanescent light; and a light amount adjustment unit adjusting a light amount of the excitation light irradiated by the irradiation unit based on the wavelength multiplicity.

Abstract: Methods and apparatus to determine a capacity for a network topology are disclosed herein. An example method includes accessing a topology comprising a plurality of links; applying weights to the links; selecting a traffic element, the selected traffic element comprising a source node, a destination node, and a traffic demand; for each of the links: (a) determining for a selected link from the plurality of the links, whether the selected traffic element may be routed on the selected link without adding capacity to the selected link; and (b) applying penalties to the weights associated with the links that cannot support the selected traffic element without adding capacity; determining, based on the weights and penalties of the links, a routing path comprising at least one of the links between the source node and the destination node; and determining capacities of at least some of the links based on the routing path.

Abstract: An optical signal adjustment apparatus detects an optical signal intensity level of signal light components with multiple different wavelengths for each of the wavelengths in an optical detection unit and adjusts the signal light components with the wavelengths for each of the wavelengths in a variable optical attenuator to make the optical signal intensity levels of the signal light components uniform. The apparatus includes a control unit configured to successively select a detection signal associated with each of the wavelengths from the optical detection unit and generate a control signal for the wavelength based on the selected detection signal. The control signal generated by the control unit is supplied to the variable optical attenuator associated with the selected detection signal.