Methods, systems, and optical power controllers are disclosed. Various problems caused by the use of a single L0 power controller in the prior art are addressed by using first and second L0 power controllers with the first L0 power controller managing first optical components with the optical network, and the second L0 power controller managing second optical components within the optical network.

An ONU communicates with an OLT that can transmit optical signals having different wavelengths simultaneously and receive optical signals having different wavelengths simultaneously. The ONU includes: an optical transceiver that receives any one of the optical signals that the OLT can transmit and transmits any one of the optical signals that the OLT can receive; a communication failure detection unit that detects a communication failure between the OLT and the ONU; and a wavelength selection unit that, when the communication failure detection unit detects a communication failure, changes a setting of a downstream wavelength to be received by the optical transceiver and an upstream wavelength to be transmitted by the optical transceiver.

An optical switch configuration is disclosed that gives the appearance of a logical cut in a fiber optic line. The inputs to the optical switch are redundant so that if a fiber event occurs on one input, the optical switch can switch to the other input. In the case where both paths of an optical fiber have fiber events, router convergence is delayed. One mechanism to mitigate a prolonged fiber degradation is to dampen the optical power on the output optical fiber of the optical switch, such that it creates a loss of light and appears as a clean cut of the optical fiber. Another solution uses optical switches to inject an alternate light source onto the output optical fiber, wherein the alternate light source is of a wavelength to be filtered out giving an appearance of a clean cut of the optical fiber.

Disclosed is a solution for monitoring an operation of an optical fiber. An arrangement for the purpose includes: an indicator device arranged to: receive, from an optical component, a sample of a signal conveyed in the communication channel; determine an indicator value indicative of an amount of light in the sample of the signal; and a computing device arranged to compare the indicator value to a reference value, and set a detection result to express either that the sample of the signal carries a predefined amount of light or the predefined amount of light is absent from the sample. Also disclosed is a method, a computing device, a computer program product and a communication system thereto.

A breakdown determination system includes a switching device that switches a transmission path of optical signals between an upper network and a lower network, one or more intermediate communication devices that relay communication between the upper network and the lower network, a selection device that selects a standby port of the intermediate communication devices, a measurement device that connects to the selected standby port via the switching device and measures an optical signal of the connected standby port, a determination device that determines whether an intermediate communication device including the selected standby port breaks down based on a result of measuring the optical signal, and a storage device that stores a result of determining whether the intermediate communication device breaks down.

This application provides a method and an apparatus for establishing an optical cable connection. The method includes: receiving, by a network device, a service provisioning request message including user information from a terminal device; allocating, by the network device, an optical splitter port based on the user information; sending, by the network device, a service provisioning response message to the terminal device, where the service provisioning response message includes the user information and port information; receiving, by the network device, an optical cable installation complete indication message sent by the terminal device, where the optical cable installation complete indication message carries the port identifier, the user information, and an optical cable identifier, and the optical cable identifier is used to indicate an optical cable corresponding to the user information; and storing, by the network device, a correspondence between the optical cable identifier, the port identifier, and the user information.

Systems and methods include detecting a fast fiber transient on a span based on analyzing power data, wherein the power data is for any of optical wavelengths of traffic channels, optical service channel (OSC) wavelengths, and telemetry from a network element; and responsive to detecting the fast fiber transient, causing an optical time domain reflectometer (OTDR) trace on the span with a specific configuration based on the fast fiber transient.

A state estimating device includes a pre-processing unit and an estimating unit. The pre-processing unit acquires data representing at one or more of a phase of a signal transmitted from a transmission unit of a transmission device and received at a reception unit of another transmission device via a transmission path, a reception strength, a reception quality, a voltage after conversion into an electric signal, and a signal processing parameter used in reception processing, and processes the acquired data into feature data to be used for state estimation. The estimating unit estimates a state of the transmission path, an abnormal state of the transmission unit, or an abnormal state of the reception unit, on the basis of the feature data.

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.

Techniques for maintaining equipment of a PON include determining a current optical profile for each segment of a plurality of segments of a PON, and detecting that the current optical profile of a particular segment is outside of a designated operating range. Based on the detection, drifts over time of the optical profile of the segment and of optical profiles of one or more other segments that share respective common endpoints with the segment are determined and compared, and based on the comparison, a component of the PON (e.g., an endpoint or an optical fiber) is identified as requiring maintenance. Each segment's optical profile corresponds to characteristics of optical signals delivered over the segment (e.g., attenuation, changes in frequencies, changes in power outputs, etc.), and current optical profiles of the PON's segments may be repeatedly updated over time to continuously monitor for components that need maintenance.