Abstract: A power-over-fiber system includes a power sourcing equipment including a semiconductor laser that oscillates with electric power to output feed light, a plurality of powered devices each including a photoelectric conversion element that converts the feed light from the power sourcing equipment into electric power, an optical fiber cable that transmits the feed light from the power sourcing equipment to the plurality of powered devices, and a switch element that distributes the feed light in accordance with a proportion of electric powers needed by the plurality of powered devices. In the power-over-fiber system, the switch element sequentially switches an optical path of the feed light to be distributed to the respective powered devices, with a time distribution corresponding to the proportion of the electric powers needed by the plurality of powered devices to distribute the feed light.

Abstract: A system for NETCONF based alarm management for a PON network.

Abstract: Disclosed herein are methods and systems for computing a launch power for an optical node by collecting data for an optical network segment and inputting the collected data and first power spectral density values into a machine learning model which are used to compute a first non-linear interference value. A first generalized-optical signal-to-noise ratio value is computed using the computed first non-linear interference value and amplified spontaneous emission values. At least one second generalized-optical signal-to-noise ratio value is computed using at least one second non-linear interference value, computed using at least one second power spectral density values, and the amplified spontaneous emission values. A highest generalized-optical signal-to-noise ratio value is determined by comparing the first generalized-optical signal-to-noise ratio value and the at least one second generalized-optical signal-to-noise ratio value.

Abstract: An OLT 110 includes an optical transmission/reception unit 111 to transmit and receive optical signals by time division; an abnormal-light-emission detection unit 112 to monitor the received optical signals, and detect a state in which the optical signals are being received for a predetermined period or longer as abnormal light emission in which the optical signals from one or more of the ONUs 130 are not received; an optical-communication control unit to sequentially select an ONU 130 one at a time from the plurality of ONUs 130 other than the one or more ONUs 130 as a target ONU 130, test whether the abnormal light emission is resolved by stopping transmission of the optical signal from each target ONU 130, and, if the abnormal light emission is resolved, specifies the target ONU 130 being tested as an ONU 130 that is a source of the abnormal light emission.

Abstract: A 3D object is additively formed via arranging non-conductive material relative to a receiving surface. During additive formation of the 3D object, a conductive channel is formed as part of the 3D object. In some instances, non-destructive fracture sensing is performed via measurement of an electrical parameter of the conductive channel.

Abstract: Systems and techniques are disclosed for using machine learning to dynamically detect physical impairments in lines of a subscriber network. In some implementations, per-tone data for a line of a subscriber network and data indicating a set of one or more scores is obtained. Each score included in the set of scores indicates a conditional likelihood that the line has a type of impairment with respect to a different feature subset ensemble. The per-tone data and the data indicating the set of one or more scores is provided as input to a model. The model is trained to output, for each of different sets of feature subset ensembles, a confidence score representing an overall likelihood that a particular line has a physical impairment. Data indicating a particular confidence score representing an overall likelihood that the line has the physical impairment is obtained. The particular confidence score is provided for output.

Abstract: A fail-safe wireless power transmission system having a transmitter, a receiver, a receiver functionality monitor unit, a transmitter functionality monitor unit and at least two sensors. The transmitter has at least one low emission state, and at least one high emission state, the high emission states having higher emissions and more complex safety systems. The transmitter may be precluded from switching from a low emission state to any high emission states upon detection of a receiver control unit malfunction, a transmitter control unit malfunction, a likelihood of human-accessible emission from the system greater than a predetermined level, or an inconsistency between results arising from at least two of the sensors. Two different methods of such preclusion may be used simultaneously or consecutively to improve reliability. A transmitter control unit analyzes data from the sensors, and performs calculations to determine if and what type of preclusion is needed.

Abstract: An apparatus, for example a lithography apparatus or a multi-mirror system, includes comprises a radiation source for generating radiation, a plurality of optical components for guiding the radiation in the apparatus, a plurality of actuator/sensor devices for the optical components, and a drive device for driving the actuator/sensor devices.

Abstract: A method for in-field calibration of a laser transmitter includes receiving, at an optical network unit (ONU), a downstream connection from an optical line terminal (OLT) where the ONU includes a Distributed Bragg Reflector (DBR) laser. The method further includes attempting to establish an upstream connection between the ONU and the OLT. When the ONU establishes the upstream connection to the OLT, the method also includes receiving, at the ONU, a message to initiate calibration of the ONU where the message is generated to indicate that the DBR laser is operating outside an operational state. The method further includes tuning, by the ONU, the DBR laser to the operational state by adjusting an injection current for the DBR laser.

Abstract: To enable the transmission and reception of a super-channel optical signal to continue maintaining the possible transmission capacity without providing a redundant configuration in advance even though a failure occurs in a subcarrier, an optical transmitter 10 of the present invention includes a splitting means 20 for splitting an inputted client signal so as to make frequency efficiency in optical modulation means optimized; optical modulation means 31 to 3N for modulating one of subcarriers having mutually different wavelengths with the client signal output; a multiplexing means 40 for multiplexing the modulated signals and outputting a super-channel optical signal; and a control means 50, in a state where a failure occurs in one of the subcarriers, for making a split client signal output to modulation means corresponding to a subcarrier having no failure and applying a modulation method with a higher frequency efficiency to at least one of the modulation means.

Abstract: A fault detection method and device is disclosed. The method includes obtaining, by an optical transport network (OTN) device, a first OTN frame. The first OTN frame includes a plurality of payload areas. Each payload area includes payload check information and payload data. The method further includes performing fault detection, according to the payload check information, of payload data of a payload area in which the payload check information is located. The first OTN frame is divided into a plurality of payload areas, and corresponding payload check information is carried in each payload area.

Abstract: The present invention relates to a device (1) for characterizing an interface of a structure (6), said structure (6) comprising a solid first material and a second material, the materials being separated by said interface. The device (1) comprises: means (2) for generating a first mechanical wave; means (2) for forming Brillouin oscillations; means (10) for detecting time variation of the Brillouin oscillations; means (12) for responding to the time variation of the Brillouin oscillations to identify reflection of said first mechanical wave by said interface or transmission through said interface of a second mechanical wave interfering with the first mechanical wave; and means (13) for determining the variation in amplitude of the Brillouin oscillations before and after reflection or transmission by said interface. The invention also relates to a corresponding method of characterization.

Abstract: Aspects of the subject disclosure may include, for example, a device that facilitates transmitting electromagnetic waves along a surface of a transmission medium without requiring an electrical return path that facilitates delivery of electric energy to devices, and sensing a condition that is adverse to the electromagnetic waves propagating along the surface of the transmission medium. Other embodiments are disclosed.

Abstract: Methods and systems of a disaggregated optical transport network (OTN) switching system that include using plug-in universal (PIU) modules for OTN to Ethernet transceiving and an Ethernet fabric as a switching core are disclosed. An OTN over Ethernet module in each of the PIU modules may enable various OTN functionality to be realized using the Ethernet fabric which may include multiple Ethernet switches. A virtual line card may include a logical aggregation of a kth Ethernet switch sub-port of each of the corresponding Ethernet switch ports of each of the Ethernet switches. A virtual switch fabric may include multiple virtual line cards for the OTN switching system. Each of the virtual line cards may be associated with a virtual address that may correspond to a respective PIU module. The virtual address may include a media access control address associated with the respective PIU module.

Abstract: Systems and methods are provided for an optical network unit (ONU) to automatically set its output power level for messages to be transmitted on a passive optical network. The ONU can autonomously determine the appropriate power level based on information provided to the ONU by an optical line terminal (OLT) and characterization by the ONU of optical signals it receives from the fiber. Specifically, the OLT can provide the ONU with control data indicative of the power level used by the OLT to transmit the message and the desired power level of the OLT for messages from the ONU. The ONU can measure the power level of at least one message received from the OLT and determine the path loss based on the measured power and the control data. The ONU can then automatically determine a suitable power level for its response message such that unacceptable levels of crosstalk between channels are avoided without having to perform an iterative power-leveling process that otherwise may introduce significant delays.

Abstract: Methods and systems for Ethernet fabric protection in a disaggregated OTN switching system that include PIU modules each having multiple ports for OTN to Ethernet transceiving and an Ethernet fabric as a switching core are disclosed. An OTN over Ethernet module in each of the PIU modules may enable various OTN functionality to be realized using the Ethernet fabric which may include multiple Ethernet switches. A first PIU module may detect a fault condition on an Ethernet fabric plane of the Ethernet fabric. In response to the detection, the OTN switching system may transmit the fault condition to other PIU modules to redirect optical data unit traffic away from the fault on the Ethernet fabric plane.

Abstract: During optical performance monitoring in low SNR conditions, the detection of pilot data may be more difficult because the detector may mistake noise for the pilot data signal. Systems and methods are disclosed herein that try to address this problem. In one embodiment, a pilot tone detector processes the received signal to determine a maximum correlation peak, and then performs tracking of the correlation peak over time. Unlike the pilot data signal, noise is typically more transient in nature. Therefore, if a correlation peak does not actually correspond to the pilot data signal, but instead corresponds to noise, then the correlation peak typically disappears over time when tracked. A search for a new correlation peak may then be performed. When a correlation peak is determined that actually corresponds to the pilot data signal, then the correlation peak typically remains when tracked.

Abstract: A device is configured to store information indicating a threshold bandwidth with which a multi-lane link is permitted to operate. The device may establish the multi-lane link with a peer device. The multi-lane link may include multiple lanes used to communicate data with the peer device. The device may determine fault states for the lanes included in the multi-lane link. A fault state, for a particular lane, may indicate that the particular lane is faulty. The device may determine an available bandwidth for the multi-lane link based on the fault states for the lanes. The device may selectively terminate the multi-lane link or operate the multi-lane link at the available bandwidth based on whether the available bandwidth satisfies the threshold bandwidth.

Abstract: In one embodiment, an autonomous vehicle receives a location of a fiber optic cable repeater of a fiber optic cable. The autonomous vehicle navigates the vehicle to the location of the fiber optic cable repeater and interfaces an optical time domain reflectometer (OTDR) of the autonomous vehicle with an OTDR port of the fiber optic cable repeater. The autonomous vehicle performs OTDR measuring of the fiber optic cable via the OTDR port of the fiber optic cable repeater, and sends a result of the OTDR measuring of the fiber optic cable to a supervisory device.

Abstract: An optical transmission apparatus includes a variable attenuator configured to adjust output intensity of each wavelength signal included in a multiplexed optical signal having been input; a monitor configured to measure an output spectrum of the variable attenuator; a calculation unit configured to calculate an amount of spectral narrowing and an amount of spectral surplus, based on a measured value by the monitor, and a target value set in advance; and a control unit configured to control an amount of attenuation of the variable attenuator, based on the amount of spectral narrowing and the amount of spectral surplus.

Abstract: An optical line terminal for use in a multi-wavelength network to operatively connect via a PON port by a first connection to a first network node and to operatively connect via the PON port by a second connection to a second network node, the optical line terminal being configured to operate under first network conditions by sending no data via the second connection, and to operate under second network conditions by sending data via the second connection.

Abstract: An inline-bypass switch system includes: a first inline-bypass switch appliance having a first bypass component, a second bypass component, a first switch coupled to the first bypass component and the second bypass component, and a first controller; and a second inline-bypass switch appliance having a third bypass component, a fourth bypass component, a second switch coupled to the third bypass component and the fourth bypass component, and a second controller; wherein the first controller in the first inline-bypass switch appliance is configured to provide one or more state signals that is associated with a state of the first inline-bypass switch appliance; and wherein the second controller in the second inline-bypass switch appliance is configured to control the second bypass component based at least in part on the one or more state signals.

Abstract: Proxy networks enable a source to send traffic to one or more targets through a set of nodes operating as proxies. However, proxy networks are typically nonselective (often by design), and do not enable a source to specify properties of the nodes selected as proxies to send traffic to the target. Presented herein are proxy network techniques that enable sources to specify node properties in a target request, and that utilize a set of node managers for respective subsets of nodes. For a target request specifying selected node properties, the node managers may select as proxies nodes having the node properties specified in the target request. Additionally, the techniques presented herein promote the flexibility of the proxy network (e.g., adding groups of nodes, expanding the variety of nodes and node properties, and sending various forms of traffic using any protocol to various topics on behalf of many and various sources).

Abstract: Aspects of the subject disclosure may include, for example, a device that facilitates transmitting electromagnetic waves along a surface of a wire that facilitates delivery of electric energy to devices, and sensing a condition that is adverse to the electromagnetic waves propagating along the surface of the wire. Other embodiments are disclosed.

Abstract: The present application provides a wavelength configuration method for a multi-wavelength passive optical network, which includes: scanning, by an ONU, a downstream receiving wavelength, and receiving, downstream wavelength information of each downstream wavelength channel that is broadcast by an OLT separately through each downstream wavelength channel of a multi-wavelength PON system; establishing, by the ONU, a downstream receiving wavelength mapping table, where an entry of the downstream receiving wavelength mapping table includes downstream receiving wavelength information, drive current information of a downstream optical receiver and receiving optical physical parameter information of the ONU; selecting, by the ONU, one downstream wavelength from the downstream wavelength information broadcast by the OLT, and setting, according to the drive current information of the downstream optical receiver recorded in a related entry of the downstream receiving wavelength mapping table, an operating wavelength of

Abstract: An optical transmission apparatus includes: a variable optical attenuation section configured to independently adjust, for each wavelength, attenuation of light of a plurality of wavelengths and adjust output optical power of wavelength multiplexed light that is output to an optical transmission line by adjustment of the attenuation; and a control section configured to stop, in accordance with control in which a wavelength included in the wavelength multiplexed light in a first wavelength band is wavelength-shifted to a second wavelength band that is different from the first wavelength band, adjustment of attenuation performed on the first wavelength band by the variable optical attenuation section.

Abstract: Disclosed herein is an apparatus and method for detecting an optical line fault in a Passive Optical Network (PON). The apparatus includes an optical distribution unit configured to, when a multiplexed signal of a downstream light signal and a monitoring light signal is input, distribute the multiplexed signal to an Optical Network Unit (ONU) of a first optical path and to a second optical path. An optical layer management unit is installed in the second optical path and is configured to set a time at which the monitoring light signal of the multiplexed signal provided to the second optical path is received to a starting time of monitoring light measurement, compare a monitoring light signal reflected and returned from the ONU with a signal pattern obtained when no fault occurs, and then determine whether a fault has occurred in a distribution network.

Abstract: The present invention includes novel techniques, apparatus, and systems for optical WDM communications. Tunable lasers are employed to generate respective subcarrier frequencies which represent subchannels of an ITU channel to which client signals can be mapped. In one embodiment, subchannels are polarization interleaved to reduce crosstalk. In another embodiment, polarization multiplexing is used to increase the spectral density. Client circuits can be divided and combined with one another before being mapped, independent of one another, to individual subchannels within and across ITU channels. A crosspoint switch can be used to control the client to subchannel mapping, thereby enabling subchannel protection switching and hitless wavelength switching.

Abstract: A method for optical dark section conditioning includes determining a section in an optical network is a dark section that includes connected fiber spans that are functional with no traffic carrying channels present thereon; and causing generation of at least one of broadband noise and a signal at a head end of the dark section. An apparatus configured to perform optical dark section conditioning includes logic configured to determine a section in an optical network is a dark section that includes connected fiber spans that are functional with no traffic carrying channels present thereon; and logic configured to cause generation of at least one of broadband noise and a signal at a head end of the dark section.

Abstract: This application provides a wavelength negotiation method of a multi-wavelength passive optical network, including: receiving a wavelength status table that is broadcast by an OLT over each downstream wavelength channel of a multi-wavelength PON system, where the wavelength status table is used to indicate information about available wavelengths of the multi-wavelength PON system and statistic information of registered ONUs of a corresponding wavelength channel; selecting an upstream transmit wavelength and a downstream receive wavelength according to the wavelength status table; and reporting information about the upstream transmit wavelength and information about the downstream receive wavelength to the OLT so that the OLT refreshes the wavelength status table. This application also provides a wavelength negotiation apparatus of the multi-wavelength passive optical network and a multi-wavelength passive optical network system.

Abstract: In some embodiments, an apparatus includes an optical transceiver system that includes a set of optical transmitters and a backup optical transmitter. In such embodiments, each optical transmitter from the set of optical transmitter can transmit at a unique wavelength from a set of wavelengths. The backup optical transmitter can transmit at a wavelength from the set of wavelengths when an optical transmitter from the set of optical transmitters associated with that wavelength fails. In other embodiments, an apparatus includes an optical transceiver system that includes a set of optical receivers and a backup optical receiver. The backup optical receiver can receive at a wavelength from the set of wavelengths when an optical receiver from the set of optical receivers associated with that wavelength fails.

Abstract: An apparatus and method for fault indication and localization in a Passive Optical Network (PON) comprising a multistage power splitter (100, 200, 300) with at least one 1:N splitter (120, 221, 222, 321, 322) followed by N items of 2:M splitters (131, 132, 231-233, 331-336), wherein N and M are integers greater than 1. The apparatus also comprises an Optical Time Domain Reflectometry (OTDR) device (110, 210, 310) capable of inserting an OTDR signal into the power splitter (100, 200, 300), and adapted to insert the OTDR signal between the first stage of the at least one 1:N splitter (120, 221, 222, 321, 322) and the second N items of 2:M splitters (131, 132, 231-233, 331-336).

Abstract: An arrangement at a Remote Node, a Remote Node, a Central Office, a WDM-PON and a method in an arrangement at a Remote Node, and a method in a Central Office are provided for supervision of the WDM-PON. The arrangement comprises at least one filter connected to the feeder fiber links and adapted to separate a data signal and an original OTDR signal received on either of the feeder fiber links. Further, the arrangement comprises a first splitter adapted to receive, from the at least one filter, the original OTDR signal, to split the original OTDR signal into a plurality of OTDR sub-signals and to output, to an N*M AWG, the plurality of OTDR sub-signals. The at least one filter is further adapted to output the original OTDR signal to the first splitter and to output the data signal to the AWG, thereby enabling supervision of the WDM-PON.

Abstract: Novel tools and techniques that can be used to detect network impairment, including but not limited to impairment of optical fiber networks. In an aspect, such tools and techniques can be deployed at relatively low cost, allowing pervasive deployment throughout a network. In another aspect, such tools and techniques can take advantage of a “dying gasp,” in which a network element detects a sudden drop in received optical (or electrical) power, resolution, etc. at short time scales and sends a notification across the network before the connection is completely compromised. In yet another aspect, some tools can include a supervisory function to analyze aspects of the dying gasp with the goal to determine network segments associated with an impairment and an estimate of the location of an impairment within the network.

Abstract: A system and method of operation of an optical network communication system includes: an optical fiber; an optical link attached to the optical fiber; a data transmitter for sending a downstream data message at a downstream data wavelength in the optical link; an optical time domain reflectometry (OTDR) transmitter for sending a OTDR broadcast pattern continuously at an OTDR wavelength different from the downstream data wavelength in the optical link; a broadband photo detector coupled to the optical fiber; and an OTDR receiver for receiving an OTDR reflected response pattern on the broadband photo detector during an open time slot not used for receiving an upstream data message for indicating an optical fault and for calculating an error distance along the optical fiber based on the optical fault.

Abstract: An optical transport network signal (OTM) comprising at least one optical channel is received at a first network equipment. The optical transport network signal (OTM) is processed to extract optical data units (ODUk) for each optical channel (OCh). There is detection for defects during the processing. The optical data units are retransmitted within optical transport units (OTUk) towards a second network equipment. When a defect has been detected, the retransmitting comprises inserting an optical channel transport unit alarm indication signal (OTUk-AIS) in an optical channel transport unit (OTUk) containing optical channel data units (ODUk) that are affected by the detected defect.

Abstract: A system for measuring a length of one or more spans between a first optical transceiver and a second optical transceiver in a fiber-optic network, which can determine, at a processor associated with the first optical transceiver, a round-trip time of an optical signal communicated from the first optical transceiver to the second optical transceiver and back to the first optical transceiver. The system can also determine, at the processor, a half-round-trip time by dividing the round-trip time by two. The system can also determine, at the processor, a distance between the first and the second optical transceivers by multiplying the speed of light by the half-round-trip time.

Abstract: In a first aspect, the method and apparatus of the present disclosure can be used to periodically and/or intermittently place one or more ONUs attached to a PON in a power savings mode so that an OTDR test can be performed. While in the power savings mode, the ONUs temporarily suspend their transmitter function and power down their upstream lasers. In a second aspect, the method and apparatus of the present disclosure can be used to coordinate the performance of OTDR during one or more periodic or intermittent discovery slots used to detect and register ONUs recently connected to the PON. Because new ONUs are infrequently connected to the PON and ONUs already registered are not permitted to transmit during the discovery windows, OTDR can be performed during these windows without impacting, to a great degree, the normal operation of the PON.

Abstract: A signal is conducted from a controller module onto a network via a first coupling. The signal is transmitted across the network and received at one or more receiver modules via one or more second couplings. At the one or more receiver modules, the received signal is analyzed and based upon the analysis, a determination is made as to whether a fault has occurred in the network and/or where the occurrence occurred.

Abstract: A system and method is disclosed that allows for the monitoring, analyzing and reporting on performance, availability and quality of optical network paths. The correlation of PM parameter metrics to client connections, coupled with threshold-based alarm generation provides a proactive and predictive management, reporting and analyzing of the health and effectiveness of individual path connections to alert Operational Support (OS) staff and/or customers to signal degradation and impending Network Element (NE) failures. The system and method performs in real-time processing intervals required for alarm surveillance in a telecommunications network.

Abstract: A method for detecting faults and their locations in an optical path between an optical line terminal (OLT) of and optical network units (ONUs) of a passive optical network (PON). The method comprises forming a maintenance optical link through the PON between the OLT and a collocated ONU, the OLT and its collocated ONU are each connected to an optical splitter; sending a ranging request from the OLT to the collocated ONU; in response to the ranging request, receiving, over the maintenance optical line, a ranging burst signal including at least a fault analysis detection pattern (FADP); and analyzing the FADP in the received signal by auto-correlating the FADP signal with an expected FADP signal, an uncorrelated event measured through the auto-correlation is indicative of a fault in the optical path of the PON and occurrence times of such events are indicative of the fault's location in the optical path.

Abstract: The present invention includes method and apparatus for storing provisioned information within the optical switches and retrievable by every controller. The optical switches perform failure isolation according to their provisioning information. The optical switches monitor each channel for loss of signal. The provisioning information is shared autonomously between the optical switches allowing the switches to retrieve the provisioning information of the network topology from any other optical switch in the network. Fault isolation is done by the optical switch on the level of optical switch provisioning following the paradigm of “single alarm for single fault,” thus avoiding alarm floods and ambiguous alarms, thereby saving the operator time and money.

Abstract: Optical network protection devices and protection methods including: a working line; a protection line; a determination module configured to determine the protection type of optical network; a first judgment module configured to judge whether the working line is normal according to performance parameter values of service signal in the working line and switching conditions configured for multiplexing section protection when the protection type of optical network is the multiplexing section protection; a second judgment module, configured to judge whether the working line is normal according to performance parameter values of service signal in the working line and switching conditions configured for channel section protection when the protection type of optical network is the channel section protection; a switching module, configured to take the service signal in the protection line as an output signal when working line is abnormal.

Abstract: A method includes generating a test signal and modulating the test signal. The method may also include transmitting the test signal on an optical path, where the optical path may include a number of add-drop multiplexer devices and amplifiers. The method may also include receiving the test signal at a destination device and converting the received test signal into an electrical signal. The method may further include identifying a portion of the electrical signal that is associated with the modulated test signal.

Abstract: An OLT operable in a PON and structured to perform OTDR measurements. The OLT comprises an electrical module for generating continuous downstream signals and processing received upstream burst signals according to a communication protocol of the PON; an optical module for transmitting continuous optical signals over a first wavelength, receiving optical upstream burst signals over a second wavelength, and transmitting optical upstream burst signals over a third wavelength, wherein the optical module further includes an ONU traffic processing module being electrically coupled to the optical module and the electrical module, wherein the ONU traffic processing module is configured to emulate one of a plurality of ONUs of the PON, to generate an analysis pattern to be transmitted as an optical upstream burst signal over a third wavelength, and analyze an analysis pattern received in an optical upstream burst signal for the purpose of performing the OTDR measurements.

Abstract: A diagnostic testing utility is used to perform single link diagnostics tests including an electrical loopback test, an optical loopback test, a link traffic test, and a link distance measurement test. To perform the diagnostic tests, two ports at each end of a link are identified and then statically configured by a user. The ports will be configured as D_Ports and as such will be isolated from the fabric with no data traffic flowing through them. The ports will then be used to send test frames to perform the diagnostic tests.

Abstract: The present invention enables to prevent transmission characteristics from deteriorating due to the nonlinear effect in the transmission path caused by an increase in the channel power when a cable disconnection occurs.

Abstract: An Optical Transport Network (OTN) fault localization method, an iterative OTN fault localization method, and an OTN network use OTN tandem connection monitors operating in a “Monitor” mode to provide fault localization. The methods and network use TCMs for fault localization that can be performed manually or automatically to isolate a fault in a multi-domain OTN network to a particular link, switching fabric, or transport function. Additionally, a roles-based assignment scheme is presented for automatically assigning TCM levels between domains and links in multi-domain OTN networks. The fault localization methods enable fault localization in an automated and non-intrusive manner.

Abstract: A method includes applying pulsed light to a first end of an optical fiber from an optical fault locator during a first distance test. The method includes determining an estimated distance to a fault based on the pulsed light. The method includes sending information indicative of the estimated distance to a remote device. The method also includes applying first visible light from the optical fault locator to the first end of the optical fiber to facilitate identification of the fault at a first site that is remote from the first end of the optical fiber.

Abstract: An apparatus comprising an optical transmitter, a coarse tuner coupled to the optical transmitter and having a first tuning range, a fine tuner coupled to the optical transmitter and having a second tuning range smaller than and within the first tuning range, a wavelength division demultiplexer coupled to the optical transmitter and to a plurality of optical fibers, and a detector coupled to the optical transmitter and the wavelength division demultiplexer.