Abstract: An apparatus includes an array of lasers, an array of electrical drivers, and optical filter. Each laser is configured to produce light in a corresponding wavelength-channel, wherein the wavelength-channels of different ones of the lasers are different. The electrical drivers are connected to directly modulate the lasers. Each driver produces a first driving current or voltage to cause a corresponding one of the lasers to be in a first lasing state and produces a different second driving current or voltage to cause the corresponding one of the lasers to be in a different second lasing state. The optical filter is connected to receive light output by the lasers. The optical filter selectively attenuates light from each of the lasers in the first lasing states thereof and to selectively pass light from each of the lasers in second lasing states thereof.

Abstract: The embodiments of the invention provide a method of routing convergence in a control plane of an intelligent optical network, which includes: a function unit perceiving a service link state transmitting an alarm notification message indicating a failure in a service link to a routing protocol unit when the service link is in failure; the routing protocol unit confirming a service link failure in the control plane according to the alarm notification message. The embodiments of the invention also provide an apparatus of routing convergence in a control plane of an intelligent optical network. According to the embodiments of the invention, the establishment of a new service or re-routing may be implemented within several seconds or even hundreds of milliseconds after the service link failure in the control plane occurs.

Abstract: When an ONU accommodating range is enlarged, and ONUs shorter and ONUs longer in a communication path to an OLT are accommodated in a PON at the same time, there is a need to change a light intensity at the time of transmitting a downstream signal in order that both of the ONUs receive a downstream signal from the OLT. When a near-end ONU receives a signal having a light intensity necessary to communicate between the OLT and a far-end ONU, there arises such a problem that the light intensity is as high as an ONU receiver fails. In order to eliminate the ONU failure of the above problem, prior to transmission of the downstream signal, a downstream signal transmission schedule (downstream light intensity map) is notified to all of the ONUs. An optical transceiver of the OLT has a function of adjusting an output light intensity, and adjusts the light intensity to values receivable by the individual ONUs when the signal arrives at the respective ONUs according to route distances to the respective ONUs.

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: Methods and systems for controlling power fluctuations in a network including a plurality of nodes are disclosed. A node in the network may be configured to modify power levels in accordance with either an active state or an inactive state. The node may transition to an inactive state in response to a power change that exceeds a power change threshold. The role of the node in controlling the power fluctuation in the network is reduced in the inactive state.

Abstract: Provided is a bidirectional wavelength division multiplexed passive optical network (WDM-PON) which includes a central office (CO) that transmits and receives multiplexed optical signals, a remote node (RN) that communicates with the CO, receives a multiplexed optical signal to demultiplex, and receives a demultiplexed optical signal to multiplex, an optical network unit (ONU) that transmits and receives demultiplexed optical signals to and from the RN, operational and protective backbone optical fibers that connect the CO to the RN, and operational and protective distribution optical fibers that connect the RN to the ONU.

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: Described is a method for controlling the wavelength of a laser in a wavelength division multiplexed (WDM) system. The method includes generating broadband light having a dithered optical power and a wavelength spectrum that includes a plurality of WDM wavelengths. The broadband light is spectrally filtered to generate a spectrally-sliced optical signal having a wavelength spectrum that includes one of the WDM wavelengths. The spectrally-sliced optical signal is injected into a laser and a dithered optical power of the laser is determined. A parameter of the laser is controlled in response to the determination of the dithered optical power to thereby align a wavelength of the laser to the wavelength spectrum of the spectrally-sliced optical signal.

Abstract: In an optical transmission apparatus, levels of signal lights obtained by demultiplexing a WDM signal and corresponding to channels are detected, based on which a channel in which a signal is transmitted and a channel in which no signal is transmitted are determined. An attenuation amount of a channel in which no signal is transmitted in a predetermined range from the channel in which the signal is transmitted is set to a value equal to an attenuation amount of the channel in which the signal is transmitted. An attenuation amount of a channel in which no signal is transmitted out of the predetermined range from the channel in which the signal is transmitted is set to a value larger than the attenuation amount of the channel in which the signal is transmitted. The signal lights are attenuated based on the values and multiplexed.

Abstract: Systems and methods are described for an optiplex. A method includes: conveying a first narrowcast signal to a first optical combiner; conveying a second narrowcast signal to a second optical combiner; tapping into said first narrowcast signal; monitoring a first characteristic of said first narrowcast signal; tapping into said second narrowcast signal; monitoring a second characteristic of said second narrowcast signal; combining a broadcast signal with the first narrowcast signal using the first optical combiner; and combining said broadcast signal with the second narrowcast signal using the second optical combiner.

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: In one embodiment, a method for receiving optical signals includes receiving a first set of one or more signals and a second set of one or more signals, determining a block length used to process the first set of signals, and processing the first set of signals using the block length. The first set of signals and the second set of signals are separated by a guard band. The block length is based upon the width of the guard band.

Abstract: A wavelength division multiplexing passive optical network (WPON) comprising an optical line terminal (OLT) and a plurality of optical network units (ONUs) coupled to the OLT via a power optical splitter. The OLT is configured to monitor wavelengths in use by the ONUs and to divide upstream traffic from the ONUs into multiple channels using tunable filters. Also disclosed is an OLT for a PON, the OLT comprising a plurality of receivers and a plurality of tunable filters corresponding to each of the receivers. The OLT also comprises channel control logic coupled to the tunable filters, wherein the channel control logic is configured to detect a plurality of wavelengths in use for upstream traffic in the PON and to divide the upstream traffic into multiple channels using the tunable filters. Included is a method for managing upstream traffic in a PON, the method comprising monitoring, by a processor, wavelengths in use for upstream traffic in the PON.

Abstract: An optical channel monitor, includes: a wavelength demultiplexer that demultiplexes input signal light; photodetectors that are arranged on a demultiplexed side of the wavelength demultiplexer, and receive light in a wavelength band wider than a wavelength band of the signal light; and a calculator that calculates a light level of signal light of each wavelength by means of linear compensation on the basis of a received light level of light in the wavelength band of the signal light and a received light level of light of a wavelength outside the wavelength band of the signal light at the photodetectors.

Abstract: An optical signal correction apparatus includes a power information generation unit that generates power information indicating power of optical main signal in wavelength band according to optical wavelength multiplexed signal, a power information adjusting unit that generates adjusted power information obtained by adjusting the power information according to the number of the optical main signal included in the wavelength band based on optical signal identifying information which identifies the number of the optical main signal in the wavelength band, a correction amount calculation unit that calculates a tilt amount of the optical wavelength multiplexed signal according to the adjusted power information, and a correction amount for correcting a tilt of the optical wavelength multiplexed signal according to a difference between the calculated tilt amount and a target tilt amount, and an optical signal correction unit that corrects the tilt of the optical wavelength multiplexed signal according to the correct

Abstract: A WDM signal light monitoring apparatus includes an optical delay interference circuit, a demultiplexer and a determiner. The optical delay interference circuit demultiplexes a phase-modulated WDM signal light, gives a delay difference to the demultiplexed WDM signal lights, then multiplexes the demultiplexed WDM signal lights, and thereby generates an intensity-modulated WDM signal light. The demultiplexer demultiplexes the intensity-modulated WDM signal light into signal lights of respective channels, and outputs the demultiplexed signal lights. The determiner determines the presence or absence of the signal light of each of the channels, based on the signal lights outputted from the demultiplexer.

Abstract: Provided is an optical relay system (10) which is capable of suppressing wasteful power consumption of an entire system to a low level. The optical relay system (10) includes a plurality of relay devices (30) and a network control device (20). The network control device (20) causes an optical signal to be regenerated by a regenerative repeater (35) within the relay device (30) existing at an upstream of the relay device (30) reporting that the optical signal has deteriorated by a degree exceeding a predetermined level. Further, the network control device (20) causes the regenerative repeater (35) to stop regenerating the signal in a case where deterioration of the signal remains within an allowable range even when the regenerative repeater (35) stops regenerating the signal.

Abstract: A system and method for optimizing the selection of ghost channels to mitigate the effects of polarization hole burning in a node of an optical communication system including identifying an optical communication channel in the node for use as a ghost channel, identifying a first set of degrees carrying the optical communication channel within the node, identifying a second set of degrees within the first set of degrees, the second set containing the degrees with the optical communication channel being a valid channel, identifying a third set of degrees within the first set of degrees, the third set containing degrees with the optical communication channel being sufficiently powerful, and selecting a first degree to source the ghost channel from the first set of degrees based at least on the second set of degrees and the third set of degrees.

Abstract: To provide a wavelength division multiplex device capable of detecting an abnormality in counting of a wavelength number of a wavelength multiplex signal transmitted and received between two opposing devices.

Abstract: An optical signal detecting device and an optical signal detection method which can detect true signal strength from a signal including a noise are provided. Therefore, an optical signal detecting device according to the present invention includes: at least two filter means, each of the filter means receiving an identical optical signal, having a transmission peak at a specific wavelength different from each other and having same after-pass noise intensity; a detection means for detecting output light intensity of each of the filter means; and a calculating means for calculating signal strength of a signal component of said optical signal based on said output light intensity detected by said detection means.

Abstract: For wavelength division multiplexing (WDM) communications, apparatus and methods are provided for performing tone-based optical channel monitoring that is less sensitive to stimulated Raman scattering (SRS). In tone-based optical channel monitoring, in which WDM channels are modulated with one or more tones, detecting and measuring the tone power is commonly used as a measure of signal power in each channel. In WDM systems with long fiber spans and high signal powers, however, SRS tends to transfer energy from shorter wavelengths to longer wavelengths, whereby the tones are no longer accurately indicative of the signal power of the individual wavelength channels. Apparatus and methods are provided which reduce the effect of SRS by filtering the monitored WDM signals into sub-bands and detecting each sub-band independently.

Abstract: A WDM signal monitoring system includes a measuring unit that measures power levels in a plurality of predetermined wavelength bands about a wavelength division multiplex signal, a waveform determination unit that determines an approximate waveform of each channel from each bit rate and modulation system of a plurality of channels which forms a wavelength division multiplex signal, and an approximation unit that determines a power level and a wavelength of each channel by approximating the power level in a plurality of wavelength bands which the measuring unit measured with the approximate waveform of each channel which the waveform determination unit determined.

Abstract: An optically amplified wavelength division multiplexing network has the functionality to add/drop channels at the optical add/drop multiplexing (OADM) nodes. The OADM node includes a receiver amplifier, an OADM module, and a transmitter amplifier. Once the OADM node detects a loss of signal (LOS) due to a fiber cut or network element failure upstream, the receiver amplifier is kept in operation as a noise source. The output of the receiver amplifier is immediately raised by increasing pump power to compensate for the LOS. The noise power received at the transmitter amplifier from the receiver amplifier is substantially equal to the signal power expected before LOS. The transient effect of downstream optical amplifiers is therefore completely suppressed and the inter-channel stimulated Raman scattering (SRS) induced spectrum tilt does not change. After the noise power is raised, the receiver amplifier may be shut down at a speed much slower than the speed of downstream amplifier control circuitry.

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 division multiplex optical ring network comprises optical fibre (1-4) arranged in a ring configuration and a plurality of doped fibre optical amplifiers (17-20) arranged in the ring. The spectral response in the ring is configured such in use amplified spontaneous emission (ASE) noise circulates around the ring in a lasing mode to clamp the gain of each doped fibre optical amplifier. Each optical amplifier (17-20) includes respective control means (28) which in use control the optical amplifier to produce a substantially constant output power or to maintain a substantially constant pump power. In the event of loss of the lasing peak, detection means switches the doped fibre optical amplifiers to a different mode of gain control, for example, a mode to produce constant gain at the value before the loss of the lasing peak. Optionally, after a predetermined delay, the optical amplifiers may revert to constant output power or pump power mode.

Abstract: Techniques are provided for receiving a connection request at a first network node configured to request a connection from the first network node to a second network node. At the first network node, it is determined if a path to the second network node without an optical regenerator is available for the connection. In response to determining that a path without an optical regenerator is not available, a path to the second network node is determined that has a minimum number of optical regenerators. The connection is set up using the path with the minimum number of optical regenerators.

Abstract: An algorithm is disclosed for performing channel balancing on channels between optical network elements within an optic-fiber communications system. The algorithm groups at least a portion of the channels into channel pairs, differentially adjusts the transmitter output power level of each of the channel pairs until the bit error ratio (BER) of at least one channel in each of the channel pairs exceeds a threshold, and records a respective power margin for each of the channels as the difference between the initial and final power levels. From the recorded power margins, a mean power margin is determined that is used to shift the transmitter output power level of each of the channels.

Abstract: A method and apparatus for restoration of operating conditions of a WDM optical ring network comprising a plurality of amplifiers linked together in a ring after a break or fault has occurred in the network. The method comprises in response to repair of the break or other fault, increasing output power or/and pump power of an amplifier in the network such that the output power or/and pump power increases substantially in accordance with a ramp function.

Abstract: Optical autodiscovery is provide between two optical modules to insure that when an optical signal is coupled between the two optical module, the optical signal from a first module does not interfere with operation of a second module. The autodiscovery is implemented by sending an optical identification signal from the first optical module via the coupling to the second optical module from which signal, the second optical module can verify and determined acceptance of the coupled first optical module. During this autodiscovery process, the optical identification signal from the first optical module may be attenuated or shifted in optical spectrum so as not to interfere with the operation of the second optical module. Autodiscovery may also be employed in cases where a first optical module is to receive an optical signal from a second module.

Abstract: An optical network unit for a passive optical network (10), configured to: initiate an upstream wavelength (wus) for an upstream signal (US) from the optical network unit to an optical line terminal (10); iteratively, until an iteration criterion is met, i) transmit the upstream signal (US) to the optical line terminal (10), ii) receive from the optical line terminal (10) power level data (p) for the upstream signal (US) as measured by the optical line terminal (10), and iii) set the upstream wavelength (wus) for the upstream signal (US) to a new wavelength-value; and adjust the upstream wavelength (wus) to a wavelength-value previously set for the upstream signal (US) and associated with power level data corresponding to a certain power level. A passive optical network system, the optical line terminal and related methods are also disclosed.

Abstract: The present invention relates to controlling wavelength switching in a plurality of nodes that are provided to increase the distance of signal transmission in inverse MUX transmission in which a high-speed line is divided into a plurality of low-speed lines for transmission. A maximum skew occurring between adjacent nodes is measured, and switching of wavelength channels is performed in one or a plurality of nodes on the basis of the measured maximum skew to keep the skew of the entire inverse MUX transmission system at or below a prescribed value. The optical communication device is provided with an NNI functional block to which high-speed lines on the transmission channel side are connected, and a UNI functional block to which low-speed lines on the client side are connected.

Abstract: The disclosure relates to a tunable 50 GHz and 100 GHz channel spacing DWDM transceiver, and methods of making and using the same. The transceiver comprises an electro-absorption modulation laser (EML), a system board configured to compare a preset wavelength with an actual emission wavelength of the EML, a microcontroller and one or more associated registers configured to communicate with the system board, a temperature controlling circuit configured to stabilize the actual emission wavelength of the EML; and a wavelength meter connected to the output of the EML and having an output connected to the system board. The system board may be configured to provide a feedback loop from the EML to the microcontroller. The transceiver, suitable for 50 GHz channel spacing standards, can be made from existing standard transceivers and can switch between 50 GHz and 100 GHz channel spacing modes.

Abstract: Provided is a wavelength division multiplexing transmission apparatus that enables operation control of transponders each carrying an FBTL optical module from the monitoring control unit by the same operation control as one for the transponders each carrying an NB optical module with four wavelengths assigned. For that purpose, the wavelength division multiplexing transmission apparatus includes the transponders for converting optical signals from wideband wavelengths to narrowband wavelengths, and a monitoring control unit for controlling the transponders by instructions from an operator.

Abstract: An apparatus comprising an optical modulator modulating a light in accordance with a modulation signal and an operating point of the optical modulator, to thereby output a modulated optical signal; and a controller controlling the operating point in accordance with a branched portion of the modulated optical signal and a detected intensity of the modulation signal so that the operating point is kept stable when the detected intensity falls below a predetermined value.

Abstract: The WDM optical transmission system using distributed Raman amplification, before starting operation of main signal light, transfers a plurality of lights having different wavelengths to that of the main signal light (for example Raman amplification pump lights or the like) between first and second optical transmission devices connected to opposite ends of a transmission line, monitors transmission line input and output power for each light, calculates a transmission line loss in each wavelength using the monitor results, and specifies a type of the transmission line based on a loss wavelength characteristic that can be estimated from the calculation result. Then the power of pump light provided to the transmission light is optimized in accordance with the type of transmission line.

Abstract: An optical signal identifying method and apparatus are provided. The optical signal identifying method includes: assigning signal IDs with different frequencies to optical signals with different wavelengths, where the signal IDs are controlled in an amplitude-modulation manner according to a binary data sequence; and distinguishing the optical signals with different wavelengths by using different signal IDs. A signal ID detecting method and apparatus, and an optical signal identifying and detecting system are further provided. The optical signals with different wavelengths are distinguished by using the signal IDs controlled in an amplitude-modulation manner according to the binary data sequence, and optical channels of the optical signals with different wavelengths are detected and information such as the optical power is obtained by detecting the signal IDs.

Abstract: A method for preventing a temporary traffic interruption between two client ports and the consequent state transition of the receiving port in a communication network providing for the transmission of a data stream between two clients along at least one path when a fault condition is detected in the path. The method includes the steps of monitoring the data stream directed to the receiver and, upon detecting in the data stream an error sequence capable of starting the state transition, replacing the data stream with a filling data stream to prevent the receiver from detecting an error condition, and resuming the forwarding of the received data stream after a predetermined time interval. An apparatus able to mask to the receiver for the predetermined time interval, a storage area network and a computer program product are also disclosed.

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 for engineering of a connection in a WDM photonic network with a plurality of flexibility sites connected by links comprises calculating a physical end-to-end route between a source node and a destination node and setting-up a communication path along this end-to-end route. An operational parameter of the communication path is continuously tested and compared with a test threshold. The path is declared established whenever the operational parameter is above the margin tolerance. The established path is continuously monitored by comparing the operational parameter with a maintenance threshold. A regenerator is switched into the path whenever the operational parameter is under the respective threshold, or another path is assigned to the respective connection. An adaptive channel power turn-on procedure provides for increasing gradually the power level of the transmitters in the path while measuring an error quantifier at the destination receiver until a preset error quantifier value is reached.

Abstract: A wavelength division multiplexing transmission system, the system comprising: a plurality of channels at different wavelengths, each channel comprising a transmitter, a receiver, and one or more amplifiers, the system further comprising an encoder for encoding data with a coding, and; a decoder for decoding transmitted data; prioritizing means for prioritizing the data on each channel; monitoring means for monitoring directly or indirectly, raw (uncorrected) bit errors on each channel; power adjusting means for, varying the power on a channel in response to the bit error rate.

Abstract: Systems for, and methods of, generating a visual representation of a wavelength division multiplexing (WDM) optical network and nodes thereof. In one embodiment, a system for generating a visual representation of multiple nodes of a WDM optical network includes: (1) a connectivity, pass-through and error identifier configured to identify connectivity and any pass-throughs and termination errors with respect to at least some nodes of the WDM optical network and (2) a connectivity, pass-through and error displayer coupled to the connectivity, pass-through and error identifier and configured to generate the visual representation that indicates the connectivity and the any pass-throughs and termination errors.

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: The present invention includes novel techniques, apparatus, and systems for optical WDM communications. Various wavelocker apparatus and methods are disclosed that measure the frequency offsets between signal lasers and reference lasers. The measured offsets are used to adjust the signal laser frequencies to meet their target frequencies. The absolute accuracy of the reference laser frequency is improved by measuring the absorption of the reference laser by a gas cell with known fixed absorption lines versus the reference laser frequency. Apparatus and methods are disclosed to cover scenarios in which the reference laser polarization is aligned with the signal lasers, as well as those in which the reference laser polarization is not aligned with the signal lasers. The wavelocker apparatus may or may not be located at the same network site as the signal lasers.

Abstract: The specification describes tunable optical filters improved according to the invention by designing the optical system architecture to provide a double pass of the signal being analyzed through the tunable optical filter. The benefit of double passes through the tunable optical filter is narrower linewidth and better adjacent and non-adjacent channel isolation. The invention may be implemented with any tunable optical filter which is reciprocal. The optical system architecture is preferably an optical performance monitor for a WDM system.

Abstract: An iterative method for power pre-emphasis of N optical channels in a Wavelength Division Multiplex (WDM) signal in an optical communication systems in accordance with which representative Xi characteristics are defined for the channels with among the characteristics there being included at least one characteristic that is a function of the Bit Error Rate (BER).

Abstract: In an optical data transmission system, one channel is removed from a group of wavelength division multiplexed optical channels and another channel carrying different information at the same wavelength is inserted in its place. The process occurs by adding an optical signal whose electric field is the difference between the electric field of the new and old channels. The difference calculation takes into account the phase of the incoming WDM channel and phase of the laser source of the difference signal. The method has applications in optical transmission networks as add-drop nodes and optical regenerators, for generation of high bandwidth optical signals, and for secret optical communications.

Abstract: An apparatus and a method for accurately detecting Loss of Optical Power (LOS) by noise power cancellation effect and optical power is measured at two output ports of an athermal periodic filter, wherein one output port in the optical frequency domain, is aligned with the signal channels of an input WDM signal (on-grid port), whereas the second output port is aligned complementary to the first output port (off-grid port). In a preferred embodiment, the apparatus computes the ratio of the measured optical powers at the two output ports of the periodic filter, and comparing them to a threshold value that is determined from the overall common-mode rejection ratio (CMRR) of the detection apparatus. In an alternative embodiment, the apparatus additionally compares the optical power measured at the on-grid port to a threshold power that is determined from system design parameters.

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: A WDM signal light monitoring device includes a first monitor for monitoring input-side WDM main signal light and output-side WDM main signal light for each wavelength; and a second monitor for monitoring the first monitor by comparing a monitoring result received from an upstream WDM transmission device with a monitoring result of the first monitor, wherein the monitoring result of the first monitor is transmitted to a downstream WDM transmission device in the system.

Abstract: The present invention provides a mechanism and a method for indirectly controlling a packet handling device interface from an optical management system in an packet-optical network. A mechanism is provided for controlling a packet handling device, such as a router, interface from a management system indirectly, by using optical equipment as a proxy and communicating between the optical gear and router via a peer-to-peer signaling protocol. The present invention provides a management method that allows separate management systems for the optical layer and the packet network layer and a method for managing the network across the domains.