Techniques for identifying sources of degradations within a PON include detecting a degradation pertaining to a segment of the PON and comparing the drift over time of an optical profile of the segment with respective drifts over time of optical profiles of one or more other PON segments, where pairs of segments share respective common endpoints and an optical profile of a segment corresponds to the characteristics of optical signals delivered over the segment (e.g., attenuation, changes in frequencies, changes in power outputs, etc.). The differences between the compared drift(s) over time are utilized to narrow down the candidate components (e.g., segment endpoints, optical fibers, etc.) for the source of the degradation, and may be utilized to particularly identify a particular endpoint or optical fiber as being the source. The source of the degradation may or may not be a component of the segment to which the degradation pertained.

A communication device is connected to a wavelength-multiplexed optical ring network, and performs communication by performing time-division multiplexing on optical signals at each wavelength. In a case where a control signal transmitted from the master communication device is not received in a predetermined period, the communication device instructs a scheduler unit to suspend transmission of data at a failure wavelength that is the wavelength at which the host communication device has been determined not to be operating properly, also instructs the scheduler unit to transmit the data stored in the buffer of the failure wavelength at another wavelength, and suspends allocation of new data to the buffer of the failure wavelength. Thus, the delay in transmission of data at the failure wavelength can be shortened.

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.

Methods and apparatus are provided for locating a fault in an optical communication link. In one aspect, a method comprises determining a fault in a first optical link, and determining a fault in a second optical link. The method then determines that a first portion of the first optical link is co-located with a second portion of the second optical link and identifies, as a result of determining that the first portion is co-located with the second portion, that the fault in the first optical link is located in the first portion and/or the fault in the second optical link is located in the second portion.

The invention provides a protection method against failure of AI-based QoT prediction, comprising calculating a first number of frequency slots and a consumable margin for a working lightpath that meet the traffic demand according to a method for allocating an OSNR margin for a working lightpath; calculating a second number of frequency slots and a consumable margin for the protection lightpath that meet the traffic demand according to a method for allocating an OSNR margin for the protection lightpath; and evaluating utilization of spectrum resource based on the first number of frequency slots and the second number of frequency slots and evaluating reliability of lightpath based on the consumable margin for the working lightpath. The method of the invention is more stable in practical network applications.

An optical communication system includes a plurality of optical combining/splitting units provided on a trunk fiber in series, a plurality of slave devices connected to the plurality of optical combining/splitting units, respectively, a master device connected to the trunk fiber and configured to perform optical communication with each slave device, and a monitoring apparatus. Each optical combining/splitting unit includes an optical sensor configured to detect an optical signal passing through an optical fiber and a transmitter. The transmitter determines whether or not there is an abnormality in optical communication on the basis of a detection state of the optical signal and transmits an abnormality notification including identification information of the optical combining/splitting unit to the monitoring apparatus in a case where there is an abnormality in optical communication. The monitoring apparatus holds connection relationship information indicating a connection relationship between the plurality of optical combining/splitting units along the trunk fiber. In a case where the monitoring apparatus receives the abnormality notification from at least one of the plurality of optical combining/splitting units, the monitoring apparatus specifies a failure position on the trunk fiber on the basis of identification information of each optical combining/splitting unit that has transmitted the abnormality notification and the connection relationship information.

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 monitoring system. The monitoring system may include an optical receiver configured to receive an optical signal, the receiver comprising a plurality of equalizers to partition the optical signal over a plurality of optical channels corresponding to a plurality of optical wavelengths. The monitoring system may also include an analysis component, coupled to the receiver, comprising logic, where the logic is configured to construct a plurality of sensor matrices, corresponding to the plurality of optical channels, based upon the optical signal, after reception at the receiver; determine, using the plurality of sensor matrices, a correlation between at least one pair of sensor matrices corresponding to at least one pair of optical channels of the plurality of optical channels; and determine a location of a perturbation, external to the transmission system, based upon the correlation.

This application provides an optical link fault identification method, and relate to the field of communications technologies. The method includes: obtaining performance data of a network device, extracting a feature parameter of the performance data, and identifying a fault mode on an optical link based on the feature parameter. The method resolves problems of a difficulty in fault identification and slow troubleshooting that are caused by a large quantity of devices, many line faults, and a difficulty in obtaining manual troubleshooting cases. In addition, a fault can be quickly identified when the fault occurs, improving troubleshooting efficiency. When an optical link risk does not cause a fault, deterioration of the performance data can be found in advance based on a feature, to perform identification and warning.

This application relates to distributed fibre optic sensing. A sensor apparatus includes an interrogator for repeatedly interrogating a sensing optical fibre with interrogating optical radiation and detecting radiation which is Rayleigh backscattered from within the sensing fibre. In a first, polarisation sensing mode of operation, the interrogator is optically coupled to the sensing fibre via an optical system that includes a length of optical fibre upstream of a polariser and the interrogator is configured to output coherent optical radiation with an optical power such that the interrogating radiation experiences non-linear effects when propagating in the length of optical fibre, so as to reduce coherence of the interrogating radiation. In the first mode, the interrogator determines the extent of any variation in polarisation of the backscatter radiation. The apparatus may also be operable in a second, coherent sensing mode in which the interrogator outputs optical radiation below a non-linear threshold.