A detection system includes: a signal output unit configured to output, to a measurement target, a measurement signal that exhibits a predetermined temporal change; a signal measurement unit configured to measure a response signal, to the measurement signal, from the measurement target; a calculation unit configured to calculate an impulse response of the measurement target, based on a measurement result of the response signal measured by the signal measurement unit; and a detection unit configured to detect abnormality regarding the measurement target, based on the impulse response calculated by the calculation unit.

A wavelength demultiplexer includes a photonic circuit and a control circuit that adjusts wavelength characteristics of the photonic circuit. The photonic circuit converts two orthogonal polarized waves contained in the incident light into two same polarized waves, which are supplied to a first optical demultiplexing circuit and a second optical demultiplexing circuit provided in the photonic circuit and having the same configuration. The photonic circuit supplies a total output power of monitor lights extracted from the same positions in the first optical demultiplexing circuit and the second optical demultiplexing circuit to the control circuit. The control circuit controls a first wavelength characteristic of the first optical demultiplexing circuit and a second wavelength characteristic of the second optical demultiplexing circuit based on the total output power of the monitor lights.

Techniques for predicting times-to-failure of components of a PON include generating an optical profile of a PON segment that has components including a last mile termination unit and an optical fiber received by the last mile termination unit, determining a drift over time of the segment's optical profile, and predicting the time-to-failure of a component of the segment based on the drift over time. The segment's optical profile corresponds to one or more characteristics of optical signals delivered over the segment (e.g., attenuation, changes in frequencies, changes in power outputs, etc.). Predicting the time-to-failure of the component may be based on, for example, a comparison of the drift over time of the segment's optical profile with drifts over time of other segments' optical profiles, a distance between the segment's optical profile and a boundary of a designated operating range of the PON, characteristics of the segment, etc.

The invention provides a computing device for determining and conveying a bandwidth coverage of an optical communication modality within a space, wherein the space comprises at least one optical transmitter arranged for communicating over said optical communication modality; wherein the computing device comprises a controller configured to: obtain configuration data characterizing a configuration of said space; obtain lighting data characterizing the at least one optical transmitter; determine the bandwidth coverage of the optical communication modality within the space based on the configuration data and the lighting data; wherein the computing device comprises an output interface configured to: convey a signal indicative of the bandwidth coverage of the optical communication modality within the space.

The present disclosure has an object of proposing a method and a device for estimating the state of a transmission path or an optical transmitter capable of mechanically estimating a factor causing an error with a small amount of constellation data and a low computing amount. The present disclosure provides a device for estimating a state of optical communication, the device including: a data preprocessing unit that reduces the number of data using random sampling with respect to constellation data in which an amplitude and a phase of optical communication data are represented by a polar coordinate diagram and performs distribution calculation and a dimension reduction; a learning unit that learns a dictionary matrix in sparse coding using learning constellation data processed by the data preprocessing unit; and a recognition unit that calculates a sparse coefficient using recognition constellation data processed by the data preprocessing unit and the dictionary matrix learned by the learning unit and estimates a factor causing degradation of the optical communication using the calculated sparse coefficient.

The present disclosure aims to enable communication to be performed with stable quality even when a user uses a terminal while moving. In the wireless communication system according to the present disclose, a switching control unit 15 sets switching illuminance p.sub.th for maintaining illuminance of an optical signal received by a terminal 91 at requested illuminance corresponding to throughput or higher during the time until connection switching between the communication with an optical wireless access point 92 and the communication with an RF wireless access point 93 is completed, and when the received illuminance p becomes lower than the switching illuminance p.sub.th during connection with the optical wireless access point 92, the switching control unit 15 performs connection switching from the optical wireless communication to the RF wireless communication.

A preFEC BER of a selected optical link is determined. A FEC Detected Degrade (FDD) threshold, FEC Excessive Degrade (FED) threshold, and FEC limit threshold are obtained for the selected optical link. The FDD threshold is less than the FED threshold and the FED threshold is less than the FEC limit. Based on the FDD threshold, FED threshold, the FEC limit, and a determination that a postFEC BER==0, it is determined whether a link down condition of the selected optical link can be asserted or de-asserted.

In a coherent optical receiver device, the dynamic range considerably decreases in the case of selectively receiving the optical multiplexed signals by means of the wavelength of the local oscillator light, therefore, a coherent optical receiver device according to an exemplary aspect of the invention includes a coherent optical receiver receiving optical multiplexed signals in a lump in which signal light is multiplexed; a variable optical attenuator; a local oscillator connected to the coherent optical receiver; and a first controller controlling the variable optical attenuator by means of a first control signal based on an output signal of the coherent optical receiver; wherein the coherent optical receiver includes a 90-degree hybrid circuit, a photoelectric converter, and an impedance conversion amplifier, and selectively detects the signal light interfering with local oscillation light output by the local oscillator out of the optical multiplexed signals; and the variable optical attenuator is disposed in the optical path of the optical multiplexed signals in a stage preceding the photoelectric converter, inputs the optical multiplexed signals, and outputs them to the coherent optical receiver controlling the intensity of the optical multiplexed signals based on the first control signal.

An optical signal detection system includes: a nonlinear converter that nonlinearly converts a plurality of first optical signals into a plurality of second optical signals, and also a third optical signal into a fourth optical signal; a spectrometer that obtains each of a plurality of first spectral data items from a different one of the plurality of second optical signals, and also a third spectral data item from the fourth optical signal; and a detection device that detects the third optical signal and outputs a detection result. The detection device includes: an analyzer that performs sparse principal component analysis on the plurality of first spectral data items to generate a plurality of second spectral data items; and a detector that compares the third spectral data item with each of the plurality of second spectral data items, and detects the third optical signal based on the result of the comparison.

A method and system are provided for continuously monitoring bandwidth utilization in real time on a backbone of a network. Prefixes using the highest traffic can be identified and additional bandwidth can be provisioned in the form of optical transponder wavelengths. The additional bandwidth can be an express path that passes directly through optical nodes (thereby bypassing transit network devices) to the destination optical node. A centralized controller can perform the monitoring of the network devices, decide that an express path needs to be generated, and control both the network device and the optical network nodes to generate the express path from the network device, through the optical network, to the destination network device. The controller can apply and remove IP static routes and IP addresses associated with an express path. Additionally, the controller can request the setup or tear-down of an optical wavelength within the optical network.