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.

A wavelength conversion device includes: a memory; and a processor configured to: receive transmission signal light in which first wavelength division multiplexing signal light and second wavelength division multiplexing signal light that have different wavelength bands in which a plurality of rays of main signal light is wavelength-multiplexed are combined with supervisory control signal light that relates to supervisory control of the first wavelength division multiplexing signal light and the second wavelength division multiplexing signal light from a transmission line and that demultiplexes the supervisory control signal light from the transmission signal light; detect input power of the supervisory control signal light; demultiplexer each of the first wavelength division multiplexing signal light and the second wavelength division multiplexing signal light from the transmission signal light; convert at least one of the wavelength bands of the first wavelength division multiplexing signal light and the second wavelength division multiplexing signal light.

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 disclosure provides for a method for reacquiring a communication link between a first communication device and a second communication device. The method includes using one or more processors of the first communication device to receive historical data related to the first communication device and an environment surrounding the first communication device. The one or more processors are then used to determine one or more trends in the historical data related to fading of the communication link. Based on the one or more trends, the one or more processors are used to determine a starting time and an initial search direction for a search for the communication link. The one or more processors then execute the search at the starting time from the initial search direction.

The disclosure provides for a method for reacquiring a communication link between a first communication device and a second communication device. The method includes using one or more processors of the first communication device to receive historical data related to the first communication device and an environment surrounding the first communication device. The one or more processors are then used to determine one or more trends in the historical data related to fading of the communication link. Based on the one or more trends, the one or more processors are used to determine a starting time and an initial search direction for a search for the communication link. The one or more processors then execute the search at the starting time from the initial search direction.

A method and system is described. A signal indicative of a failure of a first channel within a plurality of channels of a transmission signal traversing a signal working path in a network is received. The signal working path has a headend node, a tail-end node and an intermediate node. The first channel has a frequency band and a power level prior to failing. The signal working path is associated with a protection path. The protection path includes the intermediate node, optical cross-connects, and a transmitter supplying (ASE) light. The transmitter is activated to supply the ASE light within a frequency band and having a power level corresponding to the frequency band and power level associated with the first channel. The ASE light is supplied to a cross-connect, such that the cross-connect provides a transmission signal including the ASE light.

A passive optical communication network includes two optical line terminals configured respectively to receive a communication signal from information systems and at least two optical network units configured to receive the communication signal. At least two optical switches, one part of which is connected at input to a first terminal via a primary nominal operating path and to the second terminal via a secondary path, and the other part of which is connected at input to a second terminal via a primary nominal operating path and to the first terminal via a secondary path. Each switch being connected at output to at least one optical network unit. A command controller connected to the switches and configured to control the switches such that, when a fault is detected on a primary path, the switch associated with the path is toggled.

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.

Methods and systems for monitoring an optical network are described. An optical device may receive a data signal. The optical device may send the data signal to a test port. A measuring device may measure characteristics associated with the data signal.