Abstract: A computer-based monitoring system provides interactive topology information about a synchronized optical network (SONET). The monitoring system utilizes a trunks integrated record keeping system (TIRKS) connected to the SONET for collecting status data in a raw format. A computer system retrieves the raw format status data from TIRKS and provides the data in a simple graphical user interface to a user. The interface includes several menus from which the user may specify specific components of the SONET, and a graphical output for providing a graphical representation of the SONET. The graphical output illustrates each node and link and interactively provides more detailed information about any user selected link or node.

Abstract: Provided are an optical transponder that processes a G.709 frame that includes an overhead for operation, administration, and maintenance of an optical channel and an overhead for forward error correction, and a method of detecting and treating errors in optical-channel sublayers of the same. The method includes detecting an error signal or a maintenance signal from a G.709 frame that includes an overhead for operation, administration, and maintenance of an optical channel and an overhead for forward error correction; treating errors in a predetermined layer of a plurality of layers that requires error treatment when the error signal or the maintenance signal is detected or canceled; and investigating a reason for the errors in the predetermined layer.

Abstract: Method and apparatus for dynamic provisioning of reliable connections in the presence of multiple failures in optical networks are described. One embodiment is a method for allocation of protection paths after a failure in an optical network. The method comprises, responsive to a failure in an active lightpath, switching traffic on the active lightpath to a protection path; subsequent to the switching, identifying all active lightpaths in the network that no longer have an available protection path; and attempting to allocate a protection path to each of the identified active lightpaths.

Abstract: In an optical communication-use receiving circuit of the present invention, the pulse width of the received pulse which is a binary signal corresponding to the signal optical pulse is specified by using an integration circuit and a trigger generating circuit. If the pulse width of the received pulse is not shorter than a predetermined value, a signal having a fixed pulse width is outputted as an output signal from a one-shot pulse generating circuit, so that a pulse having a constant pulse width corresponding to the specified communication speed is outputted. Accordingly, if the pulse width deriving from the signal optical pulse is larger than a certain value, the communication is deemed as a low-speed communication, and a pulse having a constant pulse width corresponding to the communication speed is outputted. As a result, it is possible to realize a small-size receiving circuit and a small-size electronic device which require no external switching-over terminal.

Abstract: A station-side apparatus adapted for use in a passive optical network (PON) system is disclosed, which remotely collects inside information of optical network terminals (ONTs) even before completion of start-up of an optical network unit (ONU), permits an obstruction-detected ONU to send out an emergency notification message to the station-side apparatus, e.g., optical line terminal (OLP), and permits the OLT that received this message to interrupt the transmission of an upload signal toward another ONU after the elapse of a fixed length of time while at the same time receiving information from the obstruction-suffering ONU to thereby facilitate cut-and-divide or “segmentation” of obstruction. A subscriber-side device for use in the PON system is also disclosed.

Abstract: Where each of switches opposed to each other detects optical-signal shutoff or optical-signal deterioration on the reception side of its port, the switch brings a link of the port down and outputs an auto-negotiation configuration code, as an LAN signal. Upon receiving the LAN signal transmitted from the switch, a repeating-transmission apparatus transmits the transmitted signal to an auto-negotiation monitor. The auto-negotiation monitor performs code analysis for the transmitted LAN signal. Where the auto-negotiation monitor detects that the transmitted LAN signal is the auto-negotiation configuration code, it notifies a monitor apparatus that “The switch detects a failure and the link is down.”, as an alarm.

Abstract: Disclosed is an optical cross connect apparatus that is applicable to an end office node and relay node in a path. The optical cross connect apparatus includes an optical switch for generating plural optical output signals from plural optical input signals; an optical level monitor section for detecting the optical levels of the optical input signals; and a control section that is connected to the optical switch and the optical level monitor section, includes a path switching management section for retaining a path switching management table, references the path switching management table when the optical input signals detected by the optical level monitor section are found to be OFF, and judges whether the optical switch should be operated.

Abstract: An optical information transmission system comprises a plurality of optical transmitters and receivers, each having ports for exchangeable waveguides. Each transmitter has an input for receiving an enable signal assigned to it, and is adapted to generate or not to generate an optical information signal according to the status of the enable signal. A signal generator generates the enable signal whose status indicates whether the receiver is connected via a waveguide to a transmitter or not. Each signal generator is connected to one enable input by an enable control line wired separately from the waveguides and is adapted to generate the enable signal only after a test signal specific for each receiver has been received at its waveguide port. A description of the specific test signal of a receiver is transmitted to the associated transmitter.

Abstract: An integrated cable configured to communicate over much of its length using one or more optical fibers includes an electrical connector at least one end. The electrical connector at a first end of the integrated cable and an optoelectronic device coupled to or included in the other end of the integrated cable may utilize a bidirectional status link to transmit status data to each other. If the status data indicates that optical signals transmitted over the optical channels between the two devices are not potentially exposed to view, the two devices may operate above nominal eye safety limits. Otherwise, the two devices may operate at or below nominal eye safety limits. If the second optoelectronic device is not status-link enabled, the first optoelectronic device may operate at or below nominal eye safety limits.

Abstract: A method of managing forward error correction (FEC) initialization and auto-negotiation in ethernet passive optical networks includes receiving FEC data from an optical network unit (ONU 105), and the optical line terminal (OLT 103) responds to the ONU with FEC data. Upon receiving data not forward error corrected from an ONU. The OLT responds with data not coded for FEC (203). Similarly, upon receiving forward error corrected data from the OLT, the ONU responds with forward error corrected data (503); and upon receiving data not forward error corrected from the OLT, the ONU responds with data not forward error corrected (203). The communications quality from the ONU is monitored (501), if the communications quality is not sufficient, the OLT transmits forward error corrected data to the ONU; otherwise, the OLT transmits non-FEC data to the ONU.

Abstract: An optical apparatus comprising: a branching unit branching an input light modulated by DQSPK format and thereby outputting a first branched light and a second branched light; a first branch and a second branch inputting the first branched light and the second branched light, respectively, the first branch and the second branch having an interferometer, a photo detector, and discriminator and demodulating I-signal and Q-signal, respectively; and an abnormality detection unit detecting an abnormality of the input light based on a synchronized detection of a first demodulated signal output from the photo detector in the first branch and a first recovered signal output from the discriminator in the first branch, and a synchronized detection of a second demodulated signal output from the photo detector in the second branch and a second recovered signal output from the discriminator in the second branch.

Abstract: Methods and apparatuses for automatic restoration detection and automatic restoration of optical communication system are disclosed. In the methods, a first station sends an automatic restoration detection message to a second station at the opposite side of a failed link; in response to receiving an automatic restoration request message, determines that the link has been repaired in two directions, and sends an automatic restoration confirmation message to the second station; or in response to receiving the automatic restoration detection message, determines that the link from the second station to the first station has been repaired, and sends the automatic restoration request message to the second station; in response to receiving the automatic restoration confirmation message, determines that the link has been repaired in two directions; and switching to normal working states. The safety problem that the laser leakage occurs in the failed link is solved.

Abstract: An optical transmission-path fault-detection system for detecting a fault in an optical-transmission path connecting an optical communications apparatus and an optical amplifier corresponding to the communications apparatus is disclosed.

Abstract: An apparatus for shared optical performance monitoring (OPM) is provided. A wavelength sensitive device receives light at an input port and routes it wavelength selectively to a set of output ports. To perform optical performance monitoring on the output ports, a monitoring component of each output signal is extracted, and these monitoring components are then combined. A single OPM function is then performed on the combined signal. However, with knowledge of the wavelengths that were included in each output signal, a virtual OPM function can be realized for each output port. The per port functionality can include total power per port, power per wavelength per port, variable optical attentuation, dynamic gain equalization, the latter two examples requiring feedback.

Abstract: An optical network terminal, which includes an optical transmitter, monitors the status of the optical transmitter, such as the output or the power consumption of the optical transmitter, to determine when the optical transmitter is illegally transmitting. When an illegal transmission is detected, the optical network terminal removes power from the optical transmitter.

Abstract: A method and system for network wide fault isolation in an optical network are described. A single fault in a network can produce a large number of alarms at different points in an optical network. The described method and system identify the root cause alarm while masking all correlated alarms. In the embodiment of the invention, the method and system are based on a wavelength tracker technology allowing identification and tracking of individual channels in the optical network.

Abstract: Common techniques for restoring service to an optical network after a service interruption, while quick, do not to assist a service provider or a vendor in determining a true root-cause of the interruption. Oftentimes, the true root-cause remains undetermined, resulting in costly and unnecessary fixes. In contrast, an example embodiment of the invention facilitates troubleshooting and determining the true root-cause of the service interruption by: i) collecting and storing state information about a PON element prior to analyzing a fault attributed to the PON element, and ii) diagnosing a cause of the fault from the state information.

Abstract: A transmission apparatus that receives an optical signal by selecting any one of a plurality of provided optical signal transmission paths through protection control is configured to include a plurality of optical signal outputting sections that output the optical signals transmitted through said optical signal transmission paths respectively as optical signals having wavelengths that are different from each other, a wavelength selective optical switch capable of selectively outputting light of a wavelength corresponding to any one of the optical signals coming from the optical signal outputting sections on the basis of the frequency of a controlling frequency signal, and an optical switch controlling section that supplies said controlling frequency signal to the wavelength selective optical switch so as to output the optical signal coming from the optical signal transmission path side that is selected by said protection control among the optical signals coming from the optical signal outputting sections.

Abstract: An optical network unit for error detection and recovery of an optical module, and a control method thereof are provided. The optical network unit includes a passive optical network medium access control (PON MAC) to output an optical output control signal to activate a laser diode in a time slot allocated to the optical network unit, a monitor photo diode (PD) to sense whether the laser diode outputs an optical signal and generate a feedback signal and an error detection controller to determine whether optical signal output operation is abnormal by comparing the optical output control signal with the feedback optical signal and interrupting power to at least said laser diode when abnormal operation is determined.

Abstract: The present invention provides for an optical cable and methods for interconnecting modular components with optical fibers. Each optical fiber is electronically labeled with a unique serial number such that interconnections using the optical fibers can be accurately audited.

Abstract: An optical medium, whether inside or outside an internet/telecommunications backbone, is managed using a management signal at a wavelength which is distinct from wavelengths of service signals. A multiplexer multiplexes the management signal onto the optical medium, after which a demultiplexer demultiplexes the management signal for analysis. Performance of customer channels may be inferred from performance of the management signal.

Abstract: An embodiment of the invention provides a method and apparatus for restoring a connection in a network. The connection is typically a sub network connection (SNC). In an embodiment, a failed line in a link connecting a first node and a second node is detected, where the failed line is associated with a sub network connection (SNC). The sub network connection (SNC) is then mapped to an alternate line in the link. The first node will change cross connections in a switch fabric in the first node, while the second node will change cross connections in a switch fabric in the second node, so that both nodes can transmit data on the selected alternate line, in order to restore the SNC.

Abstract: A method and apparatus is presented for performing a sequence-level CRC calculation on fiber channel communications within a switching platform domain. A CRC generator searches the data communication for frames that contain the type of data for which a sequence-level CRC is desired, such as for a sequence containing SCSI data. If found, and the type of data allows multiple frames per sequence, the present invention creates a CRC value for the sequence. An intermediate CRC value is stored in a queue to allow the simultaneous calculation of sequence level CRC values for multiple frames. With inbound data, the sequence-level CRC is appended to the end of the sequence data. With outbound data, the calculated value is compared with the appended, expected value, With single-frame fiber channel protocols, the frame-level CRC value is obtained directly from the frames entering the switching platform domain.

Abstract: An optical network including multiple nodes is subject to intermittent faults that may raise alarms in the system. The invention focuses on an optical network based on the Any rate architecture. A single fault such as a client failure at a node in such a network can give rise to a loss of client signal leading to multiple alarms detected at multiple points. To alleviate this problem this invention provides switching in a special Signature signal in place of the lost client signal. By detecting the Signature signal containing a specific code, the fault on the any rate-based architecture can be uniquely identified. In addition to fault identification, the Signature signal on the network makes it possible to maintain Clock and Data Recovery Locks at downstream nodes. The Signature signal serves also as a vehicle for carrying a special optical tag called Wavekey provided by the Wavelength Tracker technology developed by the Applicant.

Abstract: An apparatus for remotely determining a fault of subscriber terminals and a method thereof, and more specifically, an apparatus by which in a passive optical network (PON) system, a central office determines a remote fault of subscriber terminals, and a method thereof are provided. The apparatus for determining a remote fault of subscriber terminals includes: a frequency analysis unit recognizing a fault occurrence of a subscriber terminal from an upstream signal and analyzing the frequency spectrum of the upstream signal; and a fault determination unit selecting a specific frequency corresponding to the shape of the spectrum, determining a diagnosis signal corresponding to the specific frequency, transmitting a message requesting to upward transmit the diagnosis signal to each ONT, finding a peak frequency from the frequency spectrum of the diagnosis signal transmitted by the ONT, determining a fault of the subscriber terminal by comparing the peak frequency with the selected specific frequency.

Abstract: Provided are a fault localization apparatus based on an optical communication network and a method thereof. In the fault localization apparatus according to the present invention, a downstream light source is used as a monitoring optical signal instead of using an additional monitoring light source and a subcarrier multiplexing (SCM) monitoring pulse signal of a certain frequency band having no interference with a frequency band of a downstream data signal is used and thus a fault position may be detected at low cost.

Abstract: Provided is a system, a tool and a method for communicating with a faulted circuit indicator (FCI), the faulted circuit indicator including a detection circuit for monitoring an electrical conductor of a power system. The system includes a remote display mounted in a wall of an enclosure and visible from outside of the enclosure and a first light emitting diode associated with the remote display. The first light emitting diode generates an optical FCI status signal in response to an occurrence of a fault in the electrical conductor. The system also includes a first microcontroller operatively coupled to the remote display and the detection circuit, and a handheld user command tool adapted to optically couple with the remote display. The handheld user command tool is also adapted to generate an optical serial communication. The optical serial communication provides data and commands for operation of the faulted circuit indicator.

Abstract: An optical transmission equipment in an optical communication system interconnecting two optical transmission equipment sets by a main transmission line and a backup transmission line. An optical amplifier amplifies and outputs optical signals from one transmission line in use, interconnecting the optical transmission equipment concerned with neighboring upstream optical transmission equipment, and outputs the optical signals including a signal component and a noise component. A controller controls an optical signal level so that a signal component in the optical signal reaches a predetermined level.

Abstract: An apparatus and a method for monitoring an optical transmission line. An optical pilot signal of a predetermined duration is transmitted along said optical transmission line and a return signal is sent back from a signal returner along the same transmission line corresponding to at least part of said optical pilot signal. The signal returner is positioned at a predetermined point along the optical transmission line. An optical detection apparatus detects said optical pilot signal and also detects said return signal. A monitoring unit receives detection signals from said optical detection apparatus and determins the time relationship between the predetermined duration of the optical pilot signal and the round-trip transit time of the optical pilot signal. A first monitoring signal is generated when the determined time relationship has a predetermined value, and at least one further monitoring signal is generated in other cases.

Abstract: A transmission line monitoring apparatus includes a first optical coupling unit, a first optical dividing unit, a second optical coupling unit, a second optical dividing unit and a monitoring unit. The first optical coupling unit couples a down data signal with a first wavelength and an examination signal with a second wavelength into a first coupled signal. The first optical dividing unit receives the first coupled signal and divides the first coupled signal into the down data signal with the first wavelength and the examination signal with the second wavelength. The second optical coupling unit couples an up data signal with the first wavelength and the examination signal from the first optical dividing unit into a second coupled signal. The second optical dividing unit receives the second coupled signal and divides the second coupled signal into the up data signal with the first wavelength and the examination signal with the second wavelength.

Abstract: A modular cross connect system for optical telecommunication networks has the optical unit divided in at least two main bodies with one section for connection comprising the collimators and a main commutation section with MEMS devices. The first section is a fixed part while the second section is a readily removable section. The two sections face each other through a window and, in the first section, optics are provided for steering all or part of the optical signals from and to the main MEMS unit to a MEMS standby or protection plane to allow replacement of the main MEMS unit without interrupting service.

Abstract: In a point-to-multipoint network of an optical line terminal (OLT) and multiple optical network units (ONUS) wherein each ONU is enabled to send a signal only within a time period enabled for the ONU, the OLT (or a system installed therein) identifies a defective one of the ONUs. For each of a given series of time periods, the OLT measures an optical reception level of an optical fiber signal in the time period. The OLT stores, in advance, in a table at least the reception level of a received signal from each ONU in association with the ONU. The reception level is measured in a normal state where signals from the ONUs are exclusively received. For each of the given series of time periods, the OLT decides whether a signal from one of the ONUs associated with the time period is exclusively received with no collision with any other signal.

Abstract: A self-healing passive optical network is disclosed. The network includes a central office and a remote node connected to the central office through a main optical fiber. The remote node transmits one portion of power of the upstream optical signal, which has been input from each of the optical network units, to the central office, and returning a remaining portion of the power of the upstream optical signal to the optical network unit. The network also includes a plurality of optical network units connected to the remote node through a plurality of distribution optical fibers. Each of the optical network units transmits an upstream optical signal to the remote node through the directly connected distribution optical fiber, and detects abnormality occurrences from a state of the upstream optical signal returning from the remote node.

Abstract: The present invention provides a subscriber line terminal device, which enables identification of the cause of abnormality when abnormality is detected in remote monitoring of a subscriber line terminating device connected to the terminal device via an optical fiber. The terminal device receives a plurality of monitoring signals sent from the terminating device via the optical fiber, the plurality of monitoring signals indicating normality or abnormality of a plurality of monitored items in the terminating device respectively. When two or more among the plurality of monitoring signals indicates abnormality, the terminal device selects a monitoring signal with high order of priority from among the two or more monitoring signals indicating abnormality, based on a prescribed order of priority.

Abstract: A method and system provide capacity-efficient restoration within an optical fiber communication system. The system includes a plurality of nodes each interconnected by optical fibers. Each optical fiber connection between nodes includes at least three channel groups with different priority levels for restoration switching in response to a connection failure. The system maintains and restores full-capacity communication services by switching at least a portion of the channel groups from a first optical fiber connection to a second optical fiber connection system based on the priority levels assigned to the channel groups. Service reliability is effectively maintained without incurring additional costs for dedicated spare optical fiber equipment by improving idle capacity utilization.

Abstract: Five electronic control units (ECU) control vehicle devices using CAN protocol. Each of ECUs is provided with a resistor and a switch for activating the resistor. A first and fifth ECUs are arranged on the leftmost and rightmost ends. Resistors of the first and fifth ECUs are used as terminating resistors to a two-wire communications line. When the two-wire communications line is broken, the first ECU sends a test signal while other ECUs excluding the fifth ECU turn on the switches from right to left. When the test signal can be received, a broken point is located on the right side of ECU that turns on its switch at this time. Thereafter ECUs on the left side of the broken point conduct communication.

Abstract: A variable dispersion compensating unit compensates an optical signal, and changes the compensation amount according to a control signal that has a given frequency. After demodulation of the compensated optical signal, error conditions of the signal are monitored and an error signal is output. A band pass filter filters the error signal for a component having a frequency equal to or less than the given frequency. Based on the component and on the control signal, a synchronous detecting circuit generates a compensation amount modification signal. The compensation amount modification signal is superposed on the control signal.

Abstract: A main line cable and a backup line cable are laid in a land portion in different routes. A land terminal station includes a break detecting unit that detects a break of the main line cable, and a path switching unit that switches a transmission path to the backup line cable. The break detecting unit detects a break of the cables based on a received-light level of a main signal transmitted from an underwater cable, or based on a received-light level of a returned monitor signal that has been output by the break detecting unit and reflected by the beach manhole. The beach manhole includes optical couplers that couple and divide the main signal for the main line cable and the backup line cable, a fiber grating that reflects the monitor signal, and an optical director.

Abstract: A method for detecting a failure network terminal in a Passive Optical Network includes: changing timeslots assigned to potential failure network terminals one by one; and determining the failure network terminal according to uplink data frames sent by the potential failure network terminals whose timeslots are changed. Embodiments of the present invention also disclose an apparatus and system for detecting a failure network terminal. The solution of the present invention may detect which Optical Network Unit/Terminal (ONU/ONT) fails and perform the corresponding processing in accordance with embodiments of the present invention, which recovers the system health and improves the network security, stability and self-healing ability.

Abstract: The embodiments of the invention provide a method of routing convergence in a control plane of an intelligent optical network, which includes: a function unit perceiving a service link state transmitting an alarm notification message indicating a failure in a service link to a routing protocol unit when the service link is in failure; the routing protocol unit confirming a service link failure in the control plane according to the alarm notification message. The embodiments of the invention also provide an apparatus of routing convergence in a control plane of an intelligent optical network. According to the embodiments of the invention, the establishment of a new service or re-routing may be implemented within several seconds or even hundreds of milliseconds after the service link failure in the control plane occurs.

Abstract: An accurate method of reporting “minutes of outage” for a SONET facility applies a set of business rules and hierarchical definitions to delete certain minutes that would otherwise be counted as “outages”. In particular, any outage minutes reported for a network element taken out of service for “planned maintenance” activities are removed prior to performing the final count. Additionally, outage minutes for a “lower level” element (such as, for example an OC1 element) that overlap in time with outage minutes reported for a “high level” element are likewise removed before the count is performed. The elimination of these non-service impacting outage minutes thus results in a more accurate reporting of the actual service impact of the counted outage minutes.

Abstract: Two multiplexing/demultiplexing sections of working and protection sides are prepared for each of a plurality of optical transmission devices which constitute a system, and the optical transmission devices are synchronized with each other to execute switching between the working and protection sides so that one of the working and protection sides can be selected for the entire system. Each expansion device collects optical line trouble information for each of the working and protection sides, and transmits to a main device. The main device integrates the information with trouble information transmitted from expansion devices per expansion device. The main device converts the integrated trouble information into point information, totals for each of the working and protection sides, compares, and decides which of the working and protection sides is to be selected.

Abstract: An ring type optical LAN device includes a master node and a plurality of slave nodes that are interconnected by an optical fiber cable. A plurality of optical bypass transmission lines are provided in correspondence with each one of the slave nodes. Each of the optical bypass transmission lines bypasses the corresponding one of the slave nodes. Each slave node includes an E/O converter and an optical cutoff circuit. Each of the E/O converters is controlled to flash for generating an optical signal, which is transmitted to a network. When any one of the slave nodes fails such that the corresponding E/O converter is maintained in a turned on state, the associated optical cutoff circuit forcibly switches the E/O converter to a turned off state. This suppresses a network crash caused by the failure maintaining the E/O converter in the turned on state.

Abstract: The disclosure is directed toward an optical transmission system comprising a primary path disposed between a first end and a second end. The primary path is configured to transmit optical signals between the first end and the second end. A secondary path is disposed between the first end and the second end. The secondary path is configured to transmit optical signals between the first end and the second end, e.g., in the event of a break in the primary path. A first variable ratio coupler is coupled to the primary path and the secondary path between the first end and the second end. The first variable ratio coupler is configured to adjust a coupling ratio between the primary path and the secondary path.

Abstract: A method for switching a transmission route in an optical network. A regenerator station extracts a main signal, and detects the input level of the main signal. When the input level falls below a threshold, the regenerator station determines that a failure occurs, and stops output of a main signal from the regenerator station, and transmits a control signal indicating occurrence of the failure to a receiver station, which separates the control signal from a main signal transmitted thereto, detects the input level of the main signal at the receiver station, analyzes the separated control signal, and determines whether or not a failure occurs. When the input level of the main signal at the receiver station falls below a threshold, or when the separated control signal indicates occurrence of a failure, the receiver station detects the occurrence of the failure, and switches the transmission route.

Abstract: An optical network includes a plurality of subnets. The subnets each include a plurality of add/drop nodes coupled to the optical ring and operable to passively add and drop traffic to and from the optical ring. The network further includes a plurality of gateway nodes. The gateway nodes are each coupled to the optical ring at a boundary between neighboring subnets and operable to selectively pass and terminate wavelengths between subnets to allow wavelength reuse in the subnets and to provide protection switching.

Abstract: An optical network includes an optical ring and at least three subnets. Each subnet includes a plurality of add/drop nodes coupled to the optical ring. The add/drop nodes are operable to passively add a first traffic stream in a first direction on the optical ring and a second traffic stream in a second direction on the optical ring. The first traffic stream comprises different content than the second traffic stream, and the first traffic stream and the second traffic stream are transmitted on the same wavelength. The network also includes a plurality of gateway nodes. The gateway nodes are each coupled to the optical ring at a boundary between neighboring subnets and are operable to selectively pass and terminate wavelengths between subnets to allow wavelength reuse in the subnets.

Abstract: A method and corresponding apparatus is disclosed for determining a particular Optical Network Terminal (ONT) in a Passive Optical Network (PON) is malfunctioning by sending a continuous stream of light up a shared fiber, which results in adversely affecting communications between the ONT and an Optical Line Terminal (OLT). The example embodiment verifies the failure is due to a faulty optical transmitter in the ONT and not a different network fault, such as a fiber optic line cut or power outage. Through the use of the example embodiment, a service provider can determine in an automated manner which specific ONT of a PON is malfunctioning.

Abstract: A system according to embodiments of the invention may include a first communication path that converts an optically-modulated source signal to a radio signal based on a detected degradation in a quality of a received optical signal, and a second communication path that converts a radio-modulated source signal to an optical signal based on a detected degradation in a quality of a received radio signal. The system has the ability to automatically adapt to diverse weather conditions to improve the reliability of a communication link without user intervention while supporting multiple modulation schemes.

Abstract: A system and method for establishing protection routes in optical mesh networks. A protection protocol is provided that utilizes a destination-to-source communication channel to establish a source-to-destination protection route. The communication channel is established from the node detecting the failed link back towards the transmitting node. As the destination-to-source communication channel is being established back towards the source node, it concurrently directs the nodes along this path to perform switching functions to subsequently allow the information originally intended for transmission via the failed link to be switched to the alternate protection path. Various manners of ascertaining the protection routes are also provided, including predetermined and/or dynamically-generated protection paths established via the destination-to-source communication channel.