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.

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 optical transmission apparatus includes an amplifier, a first output port to select a wavelength from the wavelength-division-multiplexed signal light amplified and output signal light with the selected wavelength to an operation line, a second output port to output multiplexed light obtained by multiplexing any one of first spontaneous emission light and second spontaneous emission light to a preliminary line, the first and the second spontaneous emission light being parts of spontaneous emission light generated by the amplifier, the first spontaneous emission light being in a wavelength range that is not selected, and the second spontaneous emission light being in a wavelength range other than a range of the wavelength-division-multiplexed signal light, and a judger to judge a continuity state of the operation line by using the signal light output to the operation line and a continuity state of the preliminary line.

Abstract: An optical transmission apparatus in an optical transmission system that transmits an optical signal through a transmission fiber includes a measurement device that measures Raman gain efficiency of the transmission fiber; a level determiner that determines an input level of the optical signal based on Raman gain efficiency measured by the measurement device; and a controller that controls a level of the optical signal input to the transmission fiber to become the input level determined by the level determiner.

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: A method for monitoring wavelength-division multiplexed (WDM) signal for detecting signal drift of objective signals, including generation of one or more objective signals and a guard signal. The guard signal has a wavelength that is within a range defined by a guard channel. The first and second objective signals and the guard signal are wavelength-division multiplexed to generate a wavelength-division multiplexed signal. The first objective signal, the second objective signal, and the guard signal are assigned to a first multiplexed objective channel, a second multiplexed objective channel, and a multiplexed guard channel, respectively. The wavelength-division multiplexed signal is received by a monitor and then the error rate of the multiplexed guard channel is determined.

Abstract: A channel power estimator for estimating the power of each channel in a wavelength division multiplexed (WDM) signal, comprising filter means to select and output a sub-band of an incoming WDM signal, function application means to apply a weighting function at least once to the output from the filter means and then output the weighted signal to reconstruction means, storage means for storing optical characteristic data on at least the function application means, wherein the reconstruction means calculates an estimation of the power distribution of the incoming WDM signal using the weighted signal and the optical characteristic data.

Abstract: Described is a method and system for reducing system penalty from polarization mode dispersion. The method includes receiving a plurality of signals at a receiving end of a transmission line, each signal being received on one of a plurality of channels of the transmission line and measuring a signal degradation of at least one of the channels of the transmission line. An amount of adjustment of a polarization controller is determined based on the signal degradation, the amount of adjustment being selected to reduce the polarization mode dispersion. The amount of adjustment is then transmitted to the polarization controller.

Abstract: Embodiments of the present invention relate to systems and methods for distributing an intentionally skewed optical-clock signal to nodes of a source synchronous computer system. In one system embodiment, a source synchronous system comprises a waveguide, an optical-system clock optically coupled to the waveguide, and a number of nodes optically coupled to the waveguide. The optical-system clock generates and injects a master optical-clock signal into the waveguide. The master optical-clock signal acquiring a skew as it passes between nodes. Each node extracts a portion of the master optical-clock signal and processes optical signals using the portion of the master optical-clock signal having a different skew for the respective extracting node.

Abstract: An optical channel monitor includes: a first optical device to include first, second and third optical ports, light input through the first optical port being led to the second optical port, light input through the second optical port being led at least to the third optical port; a second optical device to include fourth, fifth and sixth optical ports, light input through the fourth optical port being led to the fifth optical port, light input through the fifth optical port being led at least to the sixth optical port; an optical filter to include seventh and eighth optical ports optically connected to the second and fifth optical ports, respectively, a specified wavelength being transmitted between the seventh and eighth optical ports; a first photo detector to detect light output from the sixth optical port; and a second photo detector to detect light output from the third optical port.

Abstract: Optical networks occasionally experience a fault along a communications path. Service providers prefer to have an alternative communications path available to enable users to still communicate in a seamless manner. Accordingly, a method and corresponding apparatus for providing path protection for dedicated paths in an optical network is provided.

Abstract: Methods and systems are disclosed including receiving, by circuitry of a node conforming to GMPLS protocol, a signal comprising at least one of an optical signal attribute indicative of parameters of a super-channel, the super-channel including a plurality of optical carriers, each of which having a corresponding one of a plurality of wavelengths and being modulated to carry a corresponding one of a plurality of data streams, the super-channel being provisioned in the optical network as one optical channel, wherein the optical signal attribute is one of: quantity of wavelengths of the super-channel, wavelength center frequency of the super-channel, wavelength modulation of the super-channel, wavelength baudrate of the super-channel, and wavelength FEC type of the super-channel. The node further receiving information indicative of frequency slices in use by the super-channel and calculating, using algorithms conforming to CSPF-TE protocol, a path of a second super-channel.

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: Disclosed are, inter alia, methods, apparatus, computer-storage media, mechanisms, and means associated with registration of optical device characteristics of optical network devices with an optical control layer of the optical network for use in establishing compatible connections through the optical network. Especially end network devices and internal network optical devices that regenerate the optical signal register their communication capabilities of their optical interfaces with the optical control layer of an optical network. This registration allows a light path to be established through the optical network which is compatible with the registered capabilities. The optical control layer may be centralized in an optical layer server and/or distributed among optical devices in the optical network, such as on control processors in multiple, optical layer devices.

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: The present disclosure relates to an optical line terminal, the disclosure includes: an optical transmitter for generating a low speed downstream optical signal; a wavelength-multiplexer for wavelength-multiplexing the downstream optical signal; a first optical power branching tap coupler for allowing wavelength-multiplexed downstream optical signal to branch off; a wavelength band separator/coupler for separating between the wavelength-multiplexed downstream optical signal and a wavelength-multiplexed upstream optical signal; a circulation type wavelength-demultiplexer for wavelength-demultiplexing a downstream optical signal branched off by the first optical power branching tap coupler and an upstream optical signal separated by the wavelength band separator/coupler; an optical receiver for outputting a downstream electrical signal by using the wavelength-demultiplexed optical signal; and a signal processing module for controlling an optical power and a wavelength of the optical transmitter according to a s

Abstract: The present invention includes novel techniques, apparatus, and systems for optical WDM communications. Tunable lasers are employed to generate respective subcarrier frequencies which represent subchannels of an ITU channel to which client signals can be mapped. In one embodiment, subchannels are polarization interleaved to reduce crosstalk. In another embodiment, polarization multiplexing is used to increase the spectral density. Client circuits can be divided and combined with one another before being mapped, independent of one another, to individual subchannels within and across ITU channels. A crosspoint switch can be used to control the client to subchannel mapping, thereby enabling subchannel protection switching and hitless wavelength switching.

Abstract: In an n-node optical communications system, energy harvesting photodetectors at each node receive extraneous electromagnetic wavelengths that are not used for communication or other purposes by the associated node. The energy harvesting photodetectors convert the unused electromagnetic energy into reusable electrical energy. The harvested electrical energy may be used as auxiliary power at the node or elsewhere in the communication system, or stored in a battery, capacitor, or other energy storage device. The system may be used in an “all-to-all” broadcast and select communication scheme or in some other broadcast and select interconnect system that has extraneous wavelengths at node receivers.

Abstract: An optical source uses feedback to maintain a substantially fixed spacing between adjacent wavelengths in a set of wavelengths in a wavelength comb output by the optical source. In particular, a set of light sources in the optical source provide optical signals having the set of wavelengths. Moreover, the optical signals are output at diffraction angles of an optical device in the optical source (such as an echelle grating), and optical detectors in the optical source determine optical metrics associated with the optical signals. Furthermore, control logic in the optical source provides control signals to the set of light sources based on the determined optical metrics.

Abstract: An apparatus comprising a processor, wherein the processor is configured to to determine a plurality of available wavelengths that are available to transmit data over an optical network comprising a plurality of downstream nodes, select a plurality of encoding wavelengths from the available wavelengths, wherein the encoding wavelengths is a subset of the available wavelengths, and encode the data using the encoding wavelengths, wherein the encoding wavelengths dictate the switching behavior of the downstream nodes when the data is received by the downstream nodes.

Abstract: 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 wherein the pluggable module comprises Time Division Multiplexing (TDM) between an optical network interface and an electrical host interface.

Abstract: In an optical communication device, a light source is capable of varying the wavelength of light to be output. An optical multiplexer multiplexes light output from the light source with signal light received from a transmission path. To an optical medium, light output from the optical multiplexer is input. A monitor monitors light having a predetermined wavelength output from the optical medium. A wavelength number measuring unit measures the number of wavelengths of signal light transmitted through the transmission path based on the result of monitoring by the monitor.

Abstract: A transmitter to be added or reduced turns ON/OFF an optical output. A relay station and a receiving terminal station acquire the amount of fluctuation of the optical output of the received signal light when the optical output of the added transmitter is turned ON and OFF. From the amount of fluctuation of the optical output, the number of wavelengths after the addition or reduction is acquired. Without an OSC signal, each station may be informed of the number of wavelengths. Therefore, the configuration for transmitting and receiving the OSC signal is not requested, thereby reducing the total cost, appropriately controlling the gain of the optical amplifier, and successfully maintaining transmission quality.

Abstract: A method and apparatus for performing a path based quality check for a specified bit rate in a wavelength division multiplexing optical network is described. According to one embodiment of the invention, a method selects from a database one of the available paths as a currently selected path. The database stores a representation of the available paths from an access node of the optical network to other access nodes of the optical network. The method further determines a cumulative noise, cumulative chromatic dispersion, and a maximum allowable chromatic dispersion for the currently selected path. In addition, the method determines whether the currently selected path passes the path based quality check based on whether the cumulative noise is less than the maximum allowable noise at a specific bit rate and whether the chromatic dispersion is less than the maximum allowable chromatic dispersion at the specified bit rate.

Abstract: The invention relates to a method for controlling the center wavelength of at least one narrow band WDM optical channel transmitting device in a WDM network. A reflected signal portion of a WDM channel signal is evaluated at the location of a WDM transmitting device. In order to generate the reflected signal portion, the optical multiplexing device or an additional reflective filter may be used, the additional filter revealing a low reflectivity at the desired channel center wavelength and a sharply increasing reflectivity adjacent thereto. The center wavelength of the WDM transmitting device is tuned to this target center wavelength by wavelength-modulating the center wavelength with a predetermined low modulation frequency and predetermined wavelength amplitude. The center wavelength of the WDM transmitting device is tuned such that the first order modulation frequency component of the reflected signal portion is minimized.

Abstract: This invention relates to an apparatus and a method for monitoring statistical characteristics of phase noises, as well as to a coherent optical communication receiver. The apparatus for monitoring statistical characteristics of phase noises comprises an argument calculating unit (203), for obtaining an argument of a signal input thereto; an unwrapping unit (204), for unwrapping the argument obtained by the argument calculating unit (203) to obtain a phase signal (205); a delaying unit (207), for delaying the phase signal; a differentiating unit (209), for obtaining a difference between a phase signal currently obtained by the unwrapping unit (204) and a phase signal delayed by the delaying unit (207); a modulus squaring unit (210), for obtaining a square of the modulus of the difference; and an averaging unit (211), for averaging squares of moduli of a plurality of differences obtained by the modulus squaring unit (210) to obtain a mean-squared differential phase (MSDP) 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: Due to demand for more network bandwidth, a need for multi-user optical network topologies has, and will continue to, increase. A method or corresponding apparatus in embodiments of the present invention provide for an availability determination tool for determining and displaying wavelength and subrate availabilities within a network. Benefits of embodiments of a tool include allowing a user to identify the availability and capacity of any wavelength on any network, via an interactive graphical user interface, such as by using three-dimensional representations. In one embodiment, the disclosed availability determination tool allows users to locate and view any combination of available wavelengths between nodes in an optical network topology, and generate graphical and tabular reports of the availability in order to maintain an efficient and organized method or apparatus for determining and controlling wavelengths in a network.

Abstract: An optical transmission system includes optical transmission apparatuses configured to transmit wavelength-division multiplexed light signals via lightpaths, each of a pair of optical transmission apparatuses includes a conditioning unit configured to adjust the optical intensities of channels included in the wavelength-division multiplexed light signal, and one or more first processors configured to control, based on a conditioning level notified, the conditioning unit; and a managing apparatus configured to manage the pair of the optical transmission apparatuses, the managing apparatus including one or more second processors configured to compute a conditioning level on a basis of system information for respective the pair of optical transmission apparatuses in the optical transmission system.

Abstract: An attenuation amount corresponding to each wavelength at OADM node is optimized according to a calculation result in a network management system (NMS), so that an optical signal level diagram according to traffic volume variations is set, the level diagram allows each of optical signal quality indexes at terminal nodes for all wavelengths to be maintained at a required threshold value or more, and allows an optical signal quality index of a specific wavelength to be improved. Then, an FEC circuit in an optical receiver corresponding to the specific wavelength is turned OFF or the error correction ability is lowered, whereby power consumption of an overall optical network is efficiently reduced.

Abstract: A method and apparatus are provided for attenuating an optical beam. The method includes selecting a level of attenuation to be applied to the optical beam. A pattern of on-state and off-state pixels in a two dimensional spatial light modulator (SLM) is selected such that the pattern will modulate the optical beam to provide the selected level of attenuation. Finally, the optical beam is directed onto the SLM while tile pixels are arranged in the selected pattern. The pattern is periodic along a first axis and symmetric along a second axis along which an intensity distribution of die optical beam extends.

Abstract: In order to realize a multiplexer/demultiplexer in which utilization efficiency of a frequency is high, wavelength characteristics of a transmission band is flat, the cost is low, the size is small, and a wavelength and a band are variable, the multiplexer/demultiplexer includes: first light branching means for branching inputted light into plurality of pieces of light and outputting the branched pieces of light; a plurality of light wavelength separating means for separating and outputting light outputted from the first light branching means for each of predetermined frequency bands; and an optical coupling means for making outputs having frequency bands different from each other among outputs from the light wavelength separating means gather and be outputted.

Abstract: An optical transmission node including an optical preamplifier to amplify input light and an optical postamplifier to amplify light output from the optical preamplifier, includes the optical postamplifier configured to generate amplified spontaneous emission light without signals input, the optical preamplifier configured to amplify the amplified spontaneous emission light from the optical postamplifier, a loopback switch configured to discouple a path of the light output from the optical preamplifier to the optical postamplifier, and couple a path of the light output from the optical postamplifier to the optical preamplifier.

Abstract: In one aspect, the present invention embraces a wavelength locking method for causing a narrow-band wavelength spectrum of an optical transmit signal of an optical transceiver device to track a narrow-band wavelength spectrum of an optical receive signal received by the optical transceiver device Further, the present invention embraces a wavelength lockable optical transceiver device, especially for a passive optical transmission network, using this wavelength locking method.

Abstract: In accordance with the present disclosure, disadvantages and problems associated with transmitting high capacity (e.g., 400 G) optical signals may be reduced. In accordance with an embodiment of the present disclosure a method for regenerating an optical signal comprises receiving an optical signal at a network element and measuring a performance characteristic of the optical signal. The method further comprises determining that the optical signal needs regeneration based on the performance characteristic of the optical signal. The method additionally comprises performing signal regeneration of the optical signal based on the determination that the optical signal needs regeneration.

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: Systems and methods are described that that dynamically configure high-speed data link lightpaths between access routers and backbone routers at geographically dispersed locations to reassign traffic when a backbone router fails or is removed from service. Embodiments reduce the quantity of backbone router ports used in dual backbone router-homed networks.

Abstract: An optical transceiver unit for an optical WDM transmitting and receiving device is taught, with a transmitting unit to which a data signal can be fed to a specified channel input port of a multiplexer unit, wherein a separate channel wavelength is allocated to each channel input port, and the transmitting unit can be tuned with respect to optical carrier wavelength across a specified range of wavelengths. The transmitting unit is constructed so that, within the specified range of wavelengths, discrete wavelengths can be set that correspond to the channel wavelengths. In tuning mode, the controller unit can drive the transmitting unit so that the possible channel wavelengths are scanned through. The controller unit evaluates the reception signal fed to it from the receiving unit for whether abort criteria for tuning mode have been fulfilled or not, wherein the scanning process is continued until the abort criteria are fulfilled.

Abstract: An optical frequency locking method tunes each of a plurality of narrow-band optical channel transmit signals (having arbitrary channel frequency spacings) to a dedicated optical channel frequency. The method includes tapping-off a portion of the optical power of the respective channel transmit signal and filtering the tapped-off channel transmit signal using at least one optical filter device. The method also includes monitoring, as an optical input signal, the optical power of the respective channel transmit signal supplied to the at least one optical filter device and, as an optical output signal, the optical power of the filtered channel transmit signal. The method further includes tuning, within a predetermined locking range for the dedicated optical channel frequency, the optical frequency of the respective channel transmit signal such that a predetermined value for the ratio of the output signal and the input signal is reached.

Abstract: An optical packet switching system includes an optical packet transmitter, an optical packet switching apparatus, an optical amplifier, an optical packet receiver, an information gathering unit, and a peak power calculation unit. The information gathering unit collects the packet density, time-averaged power and extinction ratio from the optical packet transmitter, collects the packet density, time-averaged power and noise figure from the optical amplifier, collects the packet density, time-averaged power, switch on/off time ratio and extinction ratio from the optical packet switching apparatus, and collects the packet density and time-averaged power from the optical packet receiver. The peak power calculation unit calculates the peak power of an optical packet signal outputted from each apparatus/device based on the collected information.

Abstract: A transponder device that can form D&C paths with great versatility and high reliability without complicating a device configuration is provided, as well as an optical branching device and an optical signal transmission method. The transponder device that is independent of any directions of a wavelength switching function section at a node in a WDM transport network includes a D&C branching means that branches an optical signal input from the wavelength switching function section into one stream of dropped light and at least one stream of continued light.

Abstract: A system, a device, and a method include a network interface device that measures optical power of a passive optical device; generates optical power data, and stores the optical power data. The system, the device, and the method, also includes generating alarms based on the optical power data and communication with remote network interface devices via the passive optical device.

Abstract: A method and system are provided for improving bandwidth efficiency in an optical network by dynamically utilizing unused bandwidth located around preliminarily allocated optical channels. The method comprising monitoring actual bandwidth of the preliminarily allocated optical channels incoming to a node of the optical network, reporting the monitoring results to the controller of that node and further to a network controller, receiving at that node recommendations generated by the network controller, adjusting bandwidth of one or more of the allocated optical channels thereby releasing spare bandwidth for inserting one or more additional optical channels thereat.

Abstract: A multi-wavelength light amplifier includes a first-stage light amplifier which has a first light amplifying optical fiber amplifying a light input, a second stage light amplifier which has a second light amplifying optical fiber amplifying a first light output from the first-stage light amplifier, and an optical system which maintains a second light output of the second-stage light amplifier at a constant power level. The first-stage and second-stage light amplifiers have different gain vs wavelength characteristics so that the multi-wavelength light amplifier has no wavelength-dependence of a gain thereof.

Abstract: A network including nodes configured to provide auto-discovery and those that do not are provided in a network. The nodes that do not provide auto-discovery may be provided as end points or terminating nodes in the network. A path or circuit identifier is entered into a database at those nodes and communicated to a network management system. The network management system compares the path identifiers, and, if the two match, the network management system designates the nodes associated with the path identifiers as terminating nodes. A path through the network connecting these nodes can then be determined and monitored. In addition, fiber connection information may further be stored at each node and communicated to the network management system, such that links along the path can also be identified by the network management system. Thus, path determination and monitoring in a network including non-auto-discovering nodes can thus be obtained.

Abstract: Methods and apparatuses to provide an “Open access” service model using wavelength division multiplexing (“WDM”) passive optical networks (“PONs”) are described. A cross-connect is used to supply a first set of optical signals corresponding to a first service provider and a second set of optical signals corresponding to a second service provider to a WDM multiplexer/demultiplexer. The WDM multiplexer/de-multiplexer is used to multiplex and transmit the first set and the second set to a remote location. Another WDM multiplexer/de-multiplexer at the remote location is used to de-multiplex the first set and the second set. The first set may be supplied to a first user and the second set may be supplied to a second user. Transceivers coupled to the cross-connect may be used to generate the optical signals. For one embodiment, the transceivers include a wavelength-locked light source. For one embodiment, the transceivers are alike.

Abstract: An optical network (1) comprising an optical network element (10) comprising a first optical transmitter (14), a first controller (16), a first optical receiver and a second optical receiver and a second optical network element (12). There is provided a transmission path (30) between said first optical network element and said second optical network element. Said first optical transmitter is arranged to generate and transmit a first optical signal. Said first controller is arranged to control said first optical transmitter to generate and transmit said first optical signal at a wavelength selected from a predetermined plurality of wavelengths. Said first optical receiver is arranged to detect a backscatter portion of said first optical signal returned to said first optical network element along said transmission path by distributing scattering.

Abstract: A method comprises: acquiring, for a number nSOP of varied State-Of-Polarization analysis conditions of the input optical signal, nSOP polarization-analyzed optical spectrum traces; mathematically discriminating said signal contribution from said noise contribution within said optical signal bandwidth using said polarization-analyzed optical spectrum traces, said mathematically discriminating comprising: obtaining a differential polarization response that is related to the optical spectrum of said signal contribution by a constant of proportionality; estimating the constant of proportionality of a differential polarization response to the optical spectrum of said signal contribution; estimating the optical spectrum of said noise contribution from said input optical signal, within said optical signal bandwidth using said constant of proportionality and said differential polarization response; and determining said in-band noise parameter on said input optical signal from the mathematically discriminated noise c

Abstract: An optical network includes: an optical switch; a plurality of optical interface devices provided respectively for a plurality of servers and connected to the optical switch; and a manager to manage communication traffic of the plurality of servers. Each of the optical interface devices includes a fixed-wavelength optical transmitter and a wavelength tunable optical transmitter. A first optical path is set up via the optical switch by using the fixed-wavelength optical transmitters of the plurality of optical interface devices. The manager identifies first and second optical interface devices from among the plurality of optical interface devices in accordance with the communication traffic of the plurality of servers. A second optical path is set up between the first and second optical interface devices via the optical switch by using the wavelength tunable optical transmitters of the first and second optical interface devices.

Abstract: A network evaluation apparatus that evaluates a design of an optical network, the network evaluation apparatus including: a processor that selects two nodes, between which a lightpath is to be set up, from a plurality of nodes based on a traffic volume demand values, calculates a decreased amount of cost based on numbers of the plurality of nodes and a plurality of routers for relaying a signal transmitted between the two nodes selected, calculates an increased amount of cost based on a transmission distance of the lightpath and a number of a plurality of repeaters to be inserted according to a segment distance, and determines a value of the optical network based on the decreased amount of cost and the increased amount of cost.