Abstract: Optical transmission system transmits WDM signal from first node to second node via optical fiber. The optical transmission system includes: first OCM that detects optical power of each wavelength channel of the WDM signal in the first node; second OCM that detects optical power of each wavelength channel of the WDM signal in the second node; first processor that calculates linear SNR of each wavelength channel based on the optical power of each wavelength channel detected by the second OCM; second processor that calculates non-linear SNR of each wavelength channel based on the optical power of each wavelength channel detected by the first OCM; third processor that calculates GSNR for each wavelength channel using the linear SNR and the non-linear SNR; and fourth processor that controls transmission power of each wavelength channel of the WDM signal based on the GSNR of each wavelength channel.

Abstract: There is herein provided a method for measuring the GOSNR that can be implemented using commercial-grade transceivers and which accounts for linear optical impairments (e.g. PMD, PDL and CD) and transceiver intrinsic impairments. The method may be implemented using an Optical Spectrum Analyzer (OSA) and either the system transceivers or other commercial-grade transceivers. The proposed measurement method is based on mixed optical and electronic technologies, using an OSA and a transceiver pair. By measuring a signal quality metric Qm and the OSNR under varied power and ASE noise conditions, a constant value RBW that relates the GOSNR to the signal quality metric Qm is derived. The GOSNR is then obtained from these results.

Abstract: A method comprising obtaining, via a test system, data from one or more tests of a mobile network having at least one antenna, wherein the data includes a stream of RF samples captured over-the-air or from a Common Public Radio Interface (CPRI) or enhanced CPRI (eCPRI) link; processing the data to detect peaks; performing an analysis of any detected peaks to identify any issues on the mobile network, the analysis including determining a relative power of the detected peaks; and causing display of a user interface that includes a reporting of any the relative power. Determining a relative power includes obtaining a baseline of a subset of the data and comparing an absolute power of the peak to the baseline.

Abstract: The present invention relates to a method for optimizing performance of a multi-span optical fiber network. Each span has an associated optical transmission fiber connected to an associated optical amplifier. Gain and output power of the associated optical amplifier are respectively controlled independently. An amplifier noise figure respectively depends on the gain of the associated optical amplifier, with each associated optical amplifier further connected to launch optical signals into a remainder of a corresponding optical transmission line. The method includes the steps of for each span, computing the amplifier noise figure and a non-linear noise generated in the span based on information about the span and using the computed amplifier noise figure and the computed non-linear noise to compute an optimum launch power, and optimizing performance of the multi-span optical fiber network based on the computed optimum launch powers of all spans.

Abstract: Systems, methods, and computer-executable programs are provided for estimating margin in a network path. A method, according to one implementation, includes the step of executing a section-based analysis by estimating a margin parameter for each section of a plurality of sections forming a path through a network. The margin parameter is related to at least an available Optical Signal-to-Noise Ratio (OSNR) parameter and a Required OSNR (ROSNR) parameter. The method further includes the step of combining the estimated margin parameters for the plurality of sections to obtain a section-based estimate. In response to determining that the section-based estimate falls outside an acceptable confidence range, the method includes executing an additional path-based analysis to modify the estimate of the margin parameter.

Abstract: In some embodiments, an apparatus includes a memory and a processor operatively coupled to the memory. The processor is configured to be operatively coupled to a first optical transponder and a second optical transponder. The processor is configured to receive, from the second optical transponder, a signal representing a skew value of an optical signal and a signal representing a bit-error-rate (BER) value of the optical signal. The skew value is associated with a skew between an in-phase component of the optical signal and a quadrature component of the optical signal. The processor is configured to determine, based on at least one of the skew value or the BER value, if a performance degradation of the first optical transponder satisfies a threshold. The processor is configured to send a control signal to the first optical transponder to adjust a pulse shaping or a data baud rate of the first optical transponder.

Abstract: A method for configuring hardware-configured optical links includes generating a first optical signal comprising a slow scan of wavelength channels where the slow scan has a dwell time on a particular wavelength channel. A second optical signal is generated comprising a fast scan of wavelength channels, where the fast scan has a dwell time on a particular wavelength channel and a complete channel scan time where the slow scan dwell time is greater than or equal to complete channel scan time. The first optical signal is transmitted over a link and a portion is then detected. A pulse of light having a duration that is less than the dwell time on the particular wavelength channel of the fast scan is then detected. Client data traffic is then sent over the link in response to the detected pulse of light and the detected portion of the first optical signal.

Abstract: Provided is a technology for simultaneously monitoring a plurality of relay devices. A relay device 1 comprises a superimposing unit 2 and a monitor unit 3. The relay device 1 is interposed on an optical transmission path between optical communication devices that send and receive an optical signal, and has a function for relaying the optical signal flowing through the optical transmission path. The monitor unit 3 monitors the operation status of the relay device 1. At a predetermined timing, the superimposing unit 2 superimposes monitor unit 3 monitoring-information onto an optical signal of a primary signal flowing through the optical transmission path, by performing modulation processing on the basis of an oscillation signal having a predetermined oscillation frequency. The relay device 1 can spontaneously superimpose the monitoring information onto an optical signal and transmit same.

Abstract: A method includes receiving a sensor data stream from a sensor, determining that the sensor data stream is associated with a sensor fidelity rule specifying a triggering event, a fidelity modification, and a modification period, sampling the sensor data stream according to a first sampling interval, responsive to occurrence of a triggering event, changing the first sampling interval to a second sampling interval based on the fidelity modification, wherein the second sampling interval is different from the first sampling interval, determining whether the modification period has elapsed and whether the triggering event is active, and sampling the sensor data stream according to the second sampling interval when it is determined that the modification period has not elapsed and the triggering event is active.

Abstract: When a plurality of transport apparatuses perform their respective signal compensations using dummy lights, such compensations performed by the plurality of transport apparatuses affect each other in multiplex, with the result that such compensations produce no expected effects. A transport apparatus of the invention is characterized in that the transport apparatus comprises: a transmission unit that transmits a first signal; a generation unit that generates a dummy signal for compensating the first signal transmitted by the transmission unit; and a combination unit that combines the first signal with the dummy signal; wherein the generation unit adjusts the intensity of the dummy signal, which is to be generated, such that a second signal obtained by combining the first signal with the dummy signal will have a constant intensity.

Abstract: In some embodiments, an apparatus comprises a memory and a processor operatively coupled to the memory. The processor is configured to receive, from a forward error correction (FEC) decoder of an optical transponder, a first plurality of pre-FEC bit error rate (BER) values at a plurality of times to identify a degradation over a first transmission path. The processor is configured to determine, based on the first plurality of pre-FEC BER values, a signal pattern. The processor is configured to adjust, based on the signal pattern, a set of parameters including a first threshold and a second threshold. The processor is configured to send, in response to a second pre-FEC BER value exceeding the second threshold and being below the first threshold, a signal to trigger traffic rerouting to a second transmission path to reduce traffic loss due to the degradation over the first transmission path.

Abstract: A signal detection device including: a comparison unit that obtains data including central frequencies of optical signals respectively transmitted by a plurality of optical transmitters and a central frequency interval indicating the interval between the central frequencies, power measurement values obtained by measuring, at sampling point frequencies arranged at a prescribed sampling interval, the power of a WDM signal for which the wavelength of optical signals has been multiplexed, a sampling interval, and sampling point frequencies, that selects a selection value from among the power measurement values on the basis of the central frequency interval and the sampling interval, and that outputs a result of comparison between the selection value and a prescribed threshold; and an alarm generator that outputs a signal interruption alarm in a case where the comparison result indicates that the selection value is less than the threshold.

Abstract: A wavelength control system, method, and apparatus are described in the present disclosure. An example method include: adjusting powers of subcarriers on a super channel to a same power, where the subcarriers of the super channel includes consecutive subcarriers, a subcarrier i?1, a subcarrier i, and a subcarrier i+1; obtaining Q values of the subcarrier i?1 and the subcarrier i+1, where the Q values indicate performance of the subcarriers; calculating a Q value difference between the Q value of the subcarrier i+1 and the Q value of the subcarrier i?1, and calculating a difference between the Q value difference and a pre-obtained reference value of the subcarrier i; determining whether the absolute value of the difference is not less than the pre-obtained allowable frequency offset value, and adjusting a center wavelength of the subcarrier i according to the difference.

Abstract: Techniques for automatic bandwidth optimization of an optical communication channel in an optical network are provided. In one embodiment, a method of automatically optimizing bandwidth includes receiving, at a first optical network element, a first signal transmission transmitted according to a first set of transmission parameters over an optical communication channel established between the first optical network element and a second optical network element. The method includes determining a first quality of signal parameter associated with the first signal transmission and determining whether the first quality of signal parameter is worse than a predetermined quality of signal value. Upon determining that the first quality of signal parameter is not worse than the predetermined value, the method further includes transmitting a second set of transmission parameters to the second optical network element to further optimize the bandwidth of the optical communication channel.

Abstract: A Raman spectroscopic detection device comprising at least one microfluidic sample channel; at least one excitation waveguide for exciting a Raman signal and at least one collection waveguide for collecting a Raman signal. The output of the excitation waveguide and the input of the collection waveguide are positioned directly in the microfluidic sample channel.

Abstract: The present disclosure teaches an antenna structure comprising an antenna transmitting a signal in the terahertz band and at least one mirror, which is moveable to reflect a terahertz-band signal from a neighboring antenna. There may be a communication cell comprising a plurality of such antenna structures. The communication cell may define a coverage area. In another embodiment, the present disclosure teaches a method for controlling the antenna structures to improve the performance of the communication cell.

Abstract: An optical signal-to-noise ratio measurement device includes a measurement unit and a determination unit and measures an optical signal-to-noise ratio of an optical signal including a fixed pattern in a specified cycle. The measurement unit measures an optical signal-to-noise ratio of the optical signal respectively in a plurality of time sections in a measurement period so as to generate a plurality of measured values, a length of the measurement period being the same or substantially the same as a length of the specified cycle. The determination unit selects, from the plurality of measured values generated by the measurement unit, at least one measured value other than a worst measured value in the plurality of measured values, and determines an optical signal-to-noise ratio of the optical signal based on the selected at least one measured value.

Abstract: Systems and methods for preconditioning an optical spectrum through predicting optical spectral profiles in advance of capacity changes in an optical section include obtaining data associated with the optical section to model a current state of spectral loading in the optical section; responsive to a proposed capacity change in the current state of spectral loading, estimating a future state of spectral loading which includes the capacity change; and causing changes to one or more settings in the optical section to achieve an optimized spectral loading for the future state of spectral loading.

Abstract: A wireless communication method and an apparatus are provided. The method includes: sending, by a dual-mode terminal, first binding relationship information to an access device on a network side by using a wireless communications module; receiving, by using a visible light receiver, downlink data sent by a visible light transmitter corresponding to the access device; receiving, by using the wireless communications module, second binding relationship information sent by the access device on the network side, or, receiving, by using the visible light receiver, second binding relationship information sent by the visible light transmitter, where the second binding relationship information carries information about a correspondence between a wireless access point of the access device and the visible light transmitter; and sending, by using the wireless communications module, uplink data and/or a feedback message of the downlink data to the wireless access point of the access device.

Abstract: A network control apparatus includes a processor. The processor calculates a first OSNR corresponding to an allowable limit BER from an OSNR yield strength curve of a transmission end in a node of a transmission end. The processor acquires a reception BER of a second node of a reception end, and calculates a second OSNR corresponding to the reception BER from the OSNR yield strength curve of the transmission end. The processor calculates a first noise intensity corresponding to the allowable limit BER from the first OSNR. The processor calculates a second noise intensity corresponding to the reception BER from the second OSNR. The processor calculates a noise intensity margin, based on the first noise intensity and the second noise intensity.

Abstract: A method for enhancing optical signal-to-noise ratio measuring precision by correcting spectral resolution is provided, which can obtain optical signal-to-noise ratio with enhanced measuring precision, by measuring actual power of broad spectrum signals in a certain bandwidth, determining the sum of the power of the sampling points for the broad spectrum signals in the bandwidth by using an optical spectrum analyzer, obtaining the corrected resolution of the optical spectrum analyzer, and replacing the setting resolution of the optical spectrum analyzer with the corrected resolution. The method can effectively solve the problem of large OSNR measuring error resulted from the difference between the setting resolution and the actual resolution of optical spectrum analyzer.

Abstract: Systems and methods for Optical Transport Network (OTN) adaptation to provide sub-rate granularity and distribution include segmenting an OTN signal into N flows of cells with associated identifiers, based on tributary slots of the OTN signal, wherein N?0, and wherein the cells do not include unallocated payload from the OTN signal; switching the cells to a scheduler; and scheduling, from the scheduler, the cells for a line side modem.

Abstract: An information processing apparatus, includes: a memory that stores a wavelength defragmentation program; and a processor that performs, based on the wavelength defragmentation program, operations of: selecting an optical line according to a specific sequence in design information to allocate optical lines for respective optical wavelengths within a network; moving a selected optical line to a move-to optical wavelength; stopping, when movement of the selected optical line to the move-to optical wavelength is difficult, a selection of the optical line according to the specific sequence; and selecting a new optical line from optical lines indicated in a priority list.

Abstract: A method may include transmitting, by an optical device, a first set of channels using a first modulation format. The first set of channels may be attenuated during transmission by a filter associated with a wavelength selective switch. The method may further include transmitting, by the optical device, a second set of channels using a second modulation format. The second set of channels may be attenuated during transmission by the filter associated with the wavelength selective switch. The first set of channels and the second set of channels may be included in a super-channel. The first modulation format may be selected based on a first signal quality factor associated with attenuation by the filter associated with the wavelength selective switch. The second modulation format may be selected based on a second signal quality factor associated with attenuation by the filter associated with the wavelength selective switch.

Abstract: An optical time domain reflectometer and a method for detecting an optical fiber are disclosed. In an embodiment the optical time domain reflectometer includes: a service signal generator, a signal coupler connected to the service signal generator, an electro-optical modulator connected to the signal coupler, a transmitter connected to the electro-optical modulator, a photoelectric detector connected to the transmitter, and an analog to digital converter connected to the photoelectric detector. The optical time domain reflectometer further includes: a digital signal processor, connected to the service signal generator, the signal coupler, and the analog to digital converter, and configured to generate compensation data and a PN code sequence, receive a sampled signal sent by the analog to digital converter, and calculate a first optical fiber function.

Abstract: A device for measuring optical signal-to-noise ratio (OSNR) of a wavelength division multiplexing (WDM) optical signal including multiple wavelength channels may include a tunable optical filter to select an optical wavelength channel of the plurality of optical wavelength channels. The device may also include a polarization controller to adjust a polarization state of the selected optical wavelength channel, and a control unit to compute the OSNR of the selected wavelength channel based on a target control point.

Abstract: Methods and systems for optimizing the transmission of superchannels with different modulation formats may include pre-calculating different guardband (GB) values between superchannels and sets of power values for subcarriers to implement subcarrier power pre-emphasis (SPP). When a request for an optical path is received at a network management system, the spectral allocation of each superchannel, including a GB, is determined according to pre-specified rules based on co-propagation of the superchannels with different modulation formats.

Abstract: A signal detection device including: a comparison unit that obtains data including central frequencies of optical signals respectively transmitted by a plurality of optical transmitters and a central frequency interval indicating the interval between the central frequencies, power measurement values obtained by measuring, at sampling point frequencies arranged at a prescribed sampling interval, the power of a WDM signal for which the wavelength of optical signals has been multiplexed, a sampling interval, and sampling point frequencies, that selects a selection value from among the power measurement values on the basis of the central frequency interval and the sampling interval, and that outputs a result of comparison between the selection value and a prescribed threshold; and an alarm generator that outputs a signal interruption alarm in a case where the comparison result indicates that the selection value is less than the threshold.

Abstract: A method of determining a path in an optical server network (31) comprises obtaining an indication of an amount of premium traffic from a client network (21). The method further comprises considering paths (48) utilising an elastic capability of one or more network elements (30) of the optical server network, and selecting a path from the considered paths, wherein the path is selected based at least partially on having at least a capacity to carry the amount of premium traffic.

Abstract: An optical device includes an optical port array having first and second optical inputs for receiving optical beams and a first plurality of optical outputs associated with switching functionality and a second plurality of optical outputs associated with channel monitoring functionality. A dispersion element receives the optical beam from an input and spatially separates the beam into a plurality of wavelength components. The focusing element focuses the wavelength components. The optical path conversion system receives the plurality of wavelength components and selectively directs each one to a prescribed one of the optical ports. The photodetectors are each associated with one of the optical outputs in the second plurality of optical outputs and receive a wavelength component therefrom. The controller causes the optical path conversion system to simultaneously direct each of the wavelength components to a different one of the optical outputs of the second plurality of optical outputs.

Abstract: This application provides an apparatus and method for detecting online failure and a system. The apparatus includes: a reading unit configured to read signal to noise ratios of subcarriers from a receiver of a multicarrier optical communication system according to a predetermined monitoring time interval; a judging unit configured to judge whether there exist a first predetermined number of subcarriers of which the signal to noise ratios are less than a first threshold value; a detecting unit configured to monitor a change of distortion of the system when it is judged yes by the judging unit, and determine a cause of degradation of signal to noise ratios according to the change of distortion of the system; and a reporting unit configured to report degradation of signal to noise ratios and/or the cause of degradation of signal to noise ratios.

Abstract: Systems and methods of flexible behavior modification of a service implemented in a node during restoration in an optical network include provisioning the service on a home route with a first set of attributes; defining one or more protect routes in the network for the service, wherein each of the one or more protect routes have a corresponding set of attributes which differs from the first set of attributes; and, responsive to restoration of the service, determining a protect route of the one or more protect routes to restore the service and changing the service to have the corresponding set of attributes while on the protect route.

Abstract: A device and a method for optical measurement of a target, wherein the target is irradiated with radiation beam (15) and a measurement beam (27) is received from the target and detected. Commonly used absorbance, reflectance and fluorescence measurements do not provide adequate information in e.g. measuring small contents of sulphur compounds. The present solution provides a new Raman spectrometer which is suitable for mass applications. A target is activated with pulses of a laser diode (12). The Raman signatures are measured and integrated successively with a point detector (44). A Fabry-Perot interferometer (42) on the measurement path is successively controlled into corresponding pass bands. While high spectral resolution or range is not required it is possible to use small-sized and low cost components.

Abstract: A system for centralized automatic bias control for a plurality of modulators, including a coupler for coupling output of each of the plurality of modulators to generate a combined modulator output. A pilot insertion device inserts a pilot tone into each of the plurality of modulators such that a different pilot tone frequency is inserted for each of the plurality of modulators. A monitoring device iteratively monitoring power (Pt) of each inserted pilot tone over time to determine whether a current modulator bias is optimal for each of the plurality of modulators, and an adjuster device iteratively adjusts the modulator bias for each of the plurality of modulators for which the current modulator bias is determined to be sub-optimal until a threshold condition has been met.

Abstract: A node apparatus is installed at a node located on a route from a start node to an end node, and includes: a parameter calculating unit configured to, upon receiving routing information specifying the route and a first parameter representing an amount of signal degradation, update the first parameter by using a second parameter representing an amount of signal degradation along a transmission route to an adjacent node, and generate a third parameter representing an amount of signal degradation along a transmission route between the start node and the node, specified by the routing information; and a determination unit configured to determine reachability of the route specified by the routing information in accordance with the third parameter and a fourth parameter representing an amount of signal degradation along a transmission route from the node to the end node specified by the routing information.

Abstract: Tuning parameters of individual wavelength channels transmitted over a multimode optical fiber is provided. Characteristics of the multimode optical fiber used for an optical data link within an optical signal transmission system are retrieved. A wavelength channel grid including each central wavelength in a plurality of central wavelengths that corresponds to each particular wavelength channel in a plurality of wavelength channels used to transmit data via optical signals over the multimode optical fiber is determined. A maximum allowable data rate is calculated for each wavelength channel based on the characteristics of the multimode optical fiber at defined channel wavelengths, optical signal transceiver specifications, and data transmission performance requirements for the optical signal transmission system.

Abstract: Tuning parameters of individual wavelength channels transmitted over a multimode optical fiber is provided. Characteristics of the multimode optical fiber used for an optical data link within an optical signal transmission system are retrieved. A wavelength channel grid including each central wavelength in a plurality of central wavelengths that corresponds to each particular wavelength channel in a plurality of wavelength channels used to transmit data via optical signals over the multimode optical fiber is determined. A maximum allowable data rate is calculated for each wavelength channel based on the characteristics of the multimode optical fiber at defined channel wavelengths, optical signal transceiver specifications, and data transmission performance requirements for the optical signal transmission system.

Abstract: A device for measuring optical signal-to-noise ratio (OSNR) of a wavelength division multiplexing (WDM) optical signal including multiple wavelength channels may include a tunable optical filter to select an optical wavelength channel of the plurality of optical wavelength channels. The device may also include a polarization controller to adjust a polarization state of the selected optical wavelength channel, and a control unit to compute the OSNR of the selected wavelength channel based on a target control point.

Abstract: Embodiments of the present invention relate to a signal transmission method, transmitter, and signal transmission system. The method includes: obtaining, by a sending end, information about a power fading point of a fiber channel between the sending end and a receiving end; determining, by the sending end and according to the information about the power fading point, a subcarrier that is used to send a service signal to the receiving end on the fiber channel, where a frequency of the determined subcarrier is different from that of the power fading point; and sending, by the sending end, a service signal to the receiving end by using the determined subcarrier. According to the embodiments of the present invention, validity of a signal spectrum is ensured, and therefore it is ensured that transmitted data can be effectively recovered at a receiving end.

Abstract: Methods and systems for mitigating spectral offset may use a scanning optical filter to scan different frequencies (or wavelengths) in a signal bandwidth of an optical channel. The maximum optical power value for the optical channel may be accurate determined as well as an effective wavelength corresponding to the maximum optical power value.

Abstract: An apparatus includes an optical transmitter configured to provide an optical signal amplitude-modulated among M different levels. A constellation control module is configured to provide a drive signal to control the optical signal. A feedback module is configured to receive a measure of spacing between amplitude peaks of a symbol constellation of the optical signal. The feedback module is further configured to regulate the constellation control module to adjust the optical signal in response to the measure of spacing.

Abstract: Methods, mediums and systems described herein determine real-time in-service OSNR measurement without disrupting or turning off one or more channels of the network. An OSNR monitor described herein may be integrated with existing optical line systems. The OSNR measurements performed by the OSNR monitors are independent of the modulation format and thus, may work with all phase formats, amplitude format or a combination thereof. The real-time in-service OSNR data may be used to perform global network optimization to determine the optimal routing and data rate in the optical network. The OSNR data may be used to establish protection and restoration paths for network resiliency and to maximize data throughput.

Abstract: Disclosed are a frame error concealment method and apparatus and an audio decoding method and apparatus. The frame error concealment (FEC) method includes: selecting an FEC mode based on at least one of a state of at least one frame and a phase matching flag, with regard to a time domain signal generated after time-frequency inverse transform processing; and performing corresponding time domain error concealment processing on the current frame based on the selected FEC mode, wherein the current frame is an error frame or the current frame is a normal frame when the previous frame is an error frame.

Abstract: A network traffic monitoring apparatus and method of monitoring network traffic on a network path is disclosed. The apparatus comprises a first path arranged to receive a portion of the network traffic from the network path and a monitoring port arranged to monitor the portion of network traffic. The apparatus further comprises a switch having an input port communicatively coupled to the first path, and an output port communicatively coupled to the monitoring port. The switch is arranged to selectively toggle between the first state in which the portion of network traffic can pass from the input port to the output port and a second state, in which the portion of network traffic is prevented from passing from the input port to the output port, in dependence of a switching signal. The apparatus further comprises a second path for communicating a monitoring status signal to a network device.

Abstract: Embodiments of the present invention provide a method and an apparatus for equalizing link performance, and relate to the field of optical wavelength division multiplexing. In the present invention, target input power spectra and target output power spectra in all OMS sections in a network and single wave attenuation at a power adjusting point may be concurrently calculated based on link information of the OMS sections, fast adjustment may also be implemented for a complex network topology, and the adjustment may be implemented in a one-off manner to avoid a problem that iteration adjustment is caused by mutual impact of power adjusting points during serial adjustment in a ring network. In addition, it is not required to connect an optical path in the calculation phase, thereby eliminating reliance on a connected optical path in a process for equalizing link performance.

Abstract: A WDM optical signal is transmitted through a tunable optical filter and is polarization-nulled to find optical signal to noise ratio of individual WDM channels. The polarization nulling can be performed using a heuristic multipoint extrema search method, such as Nelder-Mead method. A plurality of checkpoints can be included in the search to verify the progress and to improve the overall robustness of a real-time polarization nulling.

Abstract: This invention concerns real-time multi-impairment signal performance monitoring. In particular it concerns an optical device, for instance a monolithic integrated photonics chip, comprising a waveguide having an input region to receive a signal for characterization, and a narrow band CW laser signal. A non-linear waveguide region to mix the two received signals. More than one output region, each equipped with bandpass filters that extract respective discrete frequency bands of the RF spectrum of the mixed signals. And, also comprising (slow) power detectors to output the extracted discrete frequency banded signals.

Abstract: The length of the optical fiber section under tension expands by a certain amount that is proportional to the level of tension applied to it. Monitoring the variations in the phase of the arriving signal allows to discover a fiber that is subject to a certain level of mechanical tension. With the method and apparatus according to the present invention it is possible to protect optical communication channels against failures in an optical transmission fiber that are caused by any kind of mechanical disturbances.

Abstract: An optical packet switching system includes a plurality of network elements for transmitting and receiving optical packet signals. Each network element includes an optical signal-to-noise ratio (OSNR) acquiring unit for acquiring the OSNR of each optical packet signal, an average value calculating unit for calculating the average value of the OSNRs of optical packet signals received within a predetermined time duration for each of the plurality of source network elements, and a difference information transmitter for calculating the difference between the calculated average value of the OSNRs and a target value of the OSNRs and then transmitting the difference to a network element corresponding to the difference. A source network element that has received the difference information adjusts the characteristics of an optical packet signal to be transmitted in a manner such that the difference is reduced.

Abstract: There is provided a system and a method for determining an in-band noise parameter representative of the optical noise contribution (such as OSNR) on a polarization-multiplexed optical Signal-Under-Test (SUT) comprising two polarized phase-modulated data-carrying contributions and an optical noise contribution.