Abstract: A border node of an optical network receives optical channel traffic parameter(s) associated with an optical channel from an optical channel originator external to the optical network. The received parameters are used to determine the suitability of at least one optical path within the optical network for an externally originating optical channel. If a suitable optical path is determined, an optical channel availability message indicating the availability at the border node of an optical path within the optical network for the optical channel is sent to the optical channel originator. The optical channel originator determines an available optical channel status of the optical channel from the received optical channel availability message for the optical channel.

Abstract: Methods and systems can suppress invalid defect detection when Out-Of-Frame (OOF) conditions occur within an Optical Transport Network. One method for processing a report of a defect during an OOF condition may include detecting the OOF condition at a downstream node, detecting an indication of the defect caused by the OOF condition, suppressing a report associated with the indication of the defect, determining whether the OOF condition is clear, determining whether the indication of the defect is still present if the OOF condition is clear; and cancelling the report if the indication of the defect is not present. A network node which processes a report of a defect during an OOF condition may include a network interface, and a processor which is coupled to the network interface. The processor may be configured to perform a method for suppressing invalid defect detection during OOF conditions.

Abstract: A transponder for performing bidirectional conversion between a client-side signal used for communication to a client device and a transmission path-side signal used for communication to a transmission path, the transponder comprising: a client-side interface for inputting/outputting the client-side signal; a transmission path-side interface for inputting/outputting the transmission path-side signal; a connection determining unit for determining which of the another client-side interface and the client device is coupled to the client-side interface; and a transmission signal generating unit for outputting, in a case where a state signal indicating a state on a transmission path side is input to the transmission path-side interface, a transmission signal indicating that the state signal has been input, from the client-side interface, wherein: the transmission signal generating unit changes a form of the transmission signal to be output from the client-side interface, based on a determination result obtained by

Abstract: An Optical Network Unit (ONU) emulator enables traffic emulation in a Gigabit-capable Passive Optical Network (GPON) that couples an Optical Line Termination (OLT) system to the ONU emulator and carries mixed types of emulated ONU traffic and real ONU traffic. The ONU emulator includes one or more emulated ONU platforms; each emulated ONU platform includes multiple ONU emulator blocks, and each ONU emulator block includes circuitry to emulate multiple emulated ONUs simultaneously. An emulated ONU platform generates upstream GPON frames according to respective profiles of the emulated ONUs, and sends the upstream GPON frames to the OLT system. At least a subset of the upstream GPON frames reach the OLT system via one or more passive optical splitters that couple the emulated ONU platform and a set of real ONUs to the OLT system. The emulated ONU platform also receives downstream GPON frames from the OLT system.

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: A method and system for identifying and, optionally, managing protection resource sharing opportunities, such as within a large-scale wavelength-division multiplexing (WDM) mesh network.

Abstract: A data transmission system and method are provided. The data transmission system includes a first link partner and an optical transceiver unit. The first link partner includes a controller. When the first link partner is in an abnormal operation mode, the controller controls the first link partner to exit from the abnormal operation mode. The optical transceiver unit is coupled between the first link partner and a second link partner and performs data transmission between the first link partner and the second link partner. According to the data transmission system and method, one link partner can accurately detect whether another link partner is coupled to the one link partner through an optical transceiver unit. Accordingly, data transmission between the two link partners can be stably performed through the optical transceiver unit.

Abstract: An optical receiver includes: an optical to electric converter that converts a received optical signal into an analog electric signal; an analog to digital converter that converts the analog electric signal obtained by the optical to electric converter into a digital signal; a digital signal processor that performs wave shaping on the digital signal; an information extract circuit that extracts information related to loss or deterioration of the optical signal from a signal propagating from the analog to digital converter to the digital signal processor or a signal in the digital signal processor; and a judging circuit that judges, based on the information extracted by the information extract circuit, whether the optical signal is lost or deteriorates.

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 passive optical network (PON) component comprising a power switch, a detector configured to monitor the power switch, and a processor configured to receive an interrupt from the detector and transmit a message comprising a first indicator that the PON component has powered down, and a second indicator giving a reason for the power down. A passive optical network (PON) component comprising a processor configured to implement a method comprising receiving an interrupt message from a detector, determining a reason for the interrupt, and transmitting a dying gasp message comprising an indicator of the reason for the interrupt. A method comprising transmitting an alarm message comprising an optical network terminal (ONT) manual power off indicator that indicates the ONT is shutting down because a subscriber has turned off its power switch.

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: Systems and methods for optical path protection for distributed antenna systems are provided. In one embodiment, a system comprises a hub and at least one node located remotely from the hub. The hub is coupled to the node by first and second fiber paths, the first fiber path comprising an uplink fiber and a downlink fiber, the second fiber path comprising an uplink fiber and a downlink fiber. The node is coupled to the downlink fibers of the first and second fiber paths via an optical combiner, and is further coupled to the uplink fibers of the first and second fiber paths via an optical splitter. The node further monitors a signal quality of a downlink optical signal and communicates to the hub information indicative of the signal quality. The hub switches communications between the hub and the node from the first to second fiber path based on the information.

Abstract: The optical receiver includes: a photoelectric conversion circuit for receiving an optical signal and converting the received optical signal into an electrical signal; a comparator for outputting a first determination signal (S1) when a voltage corresponding to the optical signal does not reach a first threshold value (TH1) and for canceling an output of the S1 when the voltage corresponding to the optical signal exceeds a second threshold value larger than TH1 during the S1 is output; a timing extraction circuit for generating a clock signal based on a frequency and a phase of the electrical signal obtained by the converting and for outputting a second determination signal (S2) when the generated clock signal does not satisfy a predetermined condition; a unit for causing the comparator to output the S1 when the S2 is output; and detects loss of optical signal while one of the S1 and S2 is output.

Abstract: Exemplary systems, devices, and methods for evaluating a link status of a fiber-optic communication system are disclosed. An exemplary transceiver device includes a transmitter configured to transmit an optical signal having a first wavelength to an additional transceiver device by way of a single optical fiber, a receiver configured to receive an optical signal having a second wavelength from the additional transceiver device by way of the single optical fiber, and a link status facility communicatively coupled to the transmitter and the receiver and configured to provide one or more visual indications of a link status between the transceiver device and the additional transceiver device. Corresponding systems, devices, and methods are also disclosed.

Abstract: A digital input interface is provided which can be checked for its reliability. The configuration of the circuit on the input side allows a high impedance for a DC input signal and a low impedance for induced AC noise, naturally attenuating any AC induced noise while maintaining the DC input signal. The interface also provides a latent failure detection engine. The latent failure detection engine can open and close an optocoupler on the input side of the interface, which discharges and charges a capacitor on the input side. The time taken for the capacitor to recharge when the optocoupler is re-opened is used to determine if there has been any threshold decay in the interface.

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: A passive optical network (PON) component comprising a power switch, a detector configured to monitor the power switch, and a processor configured to receive an interrupt from the detector and transmit a message comprising a first indicator that the PON component has powered down, and a second indicator giving a reason for the power down. A passive optical network (PON) component comprising a processor configured to implement a method comprising receiving an interrupt message from a detector, determining a reason for the interrupt, and transmitting a dying gasp message comprising an indicator of the reason for the interrupt. A method comprising transmitting an alarm message comprising an optical network terminal (ONT) manual power off indicator that indicates the ONT is shutting down because a subscriber has turned off its power switch.

Abstract: Disclosed herein is a Passive Optical Network (PON) system and method for detecting a fault in an Optical Network terminal (ONT). The PON system for detecting a fault in an ONT includes a plurality of ONTs for outputting optical signals in time slots allocated thereto in a time division access control manner and having at least one virtual ONT. An Optical Line Terminal (OLT) receives the optical signals output from the plurality of ONTs in the time division access control manner, and then detects a faulty ONT. According to the present invention, a faulty ONT that continuously outputs signals can be detected and action can be rapidly taken against system faults when a virtual ONT is formed in a plurality of ONTs connected to an OLT and then an optical signal in the section of the virtual ONT is detected, thus providing a reliable service.

Abstract: In a communication line switching method for an optical communications system in which a station-side line terminal apparatus and user-side line terminal apparatuses are connected via a plurality of redundant physical lines, the discovery of the station-side optical line terminal registering the user-side line terminal apparatuses, wherein the registered user-side line terminal apparatuses monitoring a time stamp drift error that is generated when a difference between a time stamp included in a received signal and a local time measured by the own apparatus is larger than a value set in advance and, when the time stamp drift error occurs, shifting to a deregistered state and waiting for registration by the discovery. The station-side line terminal apparatus switches a physical line from a working physical line to a backup physical line of the physical lines.

Abstract: The invention refers to a optical communication network comprising a monitoring node having a port for outputting at least one optical signal that has a first wavelength range over an optical link of the network to a reflector node of the network. In order to allow for efficient monitoring the optical link it is suggested that the reflector node comprises a wavelength selective optical reflector connected to the link, the reflector being configured for generating a monitoring signal by reflecting a part of the optical signal back into the link, the monitoring signal having a second wavelength range that is a proper sub-range of the first wavelength range and the monitoring node comprises a detector coupled with the port for determining whether the link is defective arranged for detecting the monitoring signal generated by the reflector node.

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: A joint switching method for an aggregation node, an aggregation node, and an optical network protection system including an aggregation node are provided. By monitoring information transferred between an active optical line terminal (OLT) and a broadband network gateway (BNG), the aggregation node finds a fault in time according to the monitored information and when a fault occurs, the aggregation node starts a local protection solution, enables a corresponding backup port connected to a backup OLT corresponding to the active OLT, and disables an active port connected to the active OLT. Through the method, when the active OLT is switched to the backup OLT, the aggregation node performs joint switching, which ensures normal communication.

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.

Abstract: A method and system for determining stress associated with a communication device, e.g., an optical fiber, and associated structures are disclosed. An exemplary method includes transmitting an initiated signal through a communication device, and comparing a reflected signal reflected by the communication device with the initiated signal. The method may further include determining a stress associated with the device from at least the comparison of the initiated signal and the reflected signal.

Abstract: The invention relates to a protection mechanism for a communications network. A node, a method, a computer program product and a communications network to provide protection for an optical communications network are disclosed. Communications traffic is selecting from a working path in the optical network. A first fault condition is determining on the working path. The communications traffic is selected from a protection path in the optical network in response to clearing of the first fault and determining a second fault condition on the working path within a first predetermined time period of determining the first fault condition.

Abstract: Disclosed in the present invention are an alarm processing method and device for a PON system in power-saving mode, for solving the technical problem that the PON system cannot process the alarm or exception message after the ONU enters power-saving state and the management server is misled to deem that the system is abnormal. In the present invention, when the OLT detects the alarm generated for a certain ONU, it acquires the current power-saving working state of the ONU, and if the ONU is currently in power-saving state (such as doze state, i.e. Tx mode), the OLT suppresses, discards or shields the relevant alarm by the ONU currently in power-saving state. By way of the present invention, the alarm processing pressure can be alleviated and the real state of the ONU can be reflected.

Abstract: In a communication line switching method for an optical communications system in which a station-side line terminal apparatus and user-side line terminal apparatuses are connected via a plurality of redundant physical lines, the discovery of the station-side optical line terminal registering the user-side line terminal apparatuses, wherein the registered user-side line terminal apparatuses monitoring a time stamp drift error that is generated when a difference between a time stamp included in a received signal and a local time measured by the own apparatus is larger than a value set in advance and, when the time stamp drift error occurs, shifting to a deregistered state and waiting for registration by the discovery. The station-side line terminal apparatus switches a physical line from a working physical line to a backup physical line of the physical lines.

Abstract: The embodiments of the present invention relate to the field of communication technologies, and disclose a method for transmitting impairment information, a node, and a network system. The method for transmitting impairment information includes: receiving, by a first node on a path, first impairment information from a previous hop node, and updating the first impairment information to obtain physical impairment parameters of all or a part of available wavelengths at the first node; deleting a wavelength whose physical impairment parameter at the first node exceeds a preset range; and sending second impairment information to a next hop node of the first node when a residual wavelength still exists after the wavelength whose impairment parameter exceeds the preset range is deleted. The second impairment information includes a physical impairment parameter of the residual wavelength at the first node.

Abstract: The present invention provides a method and apparatus for implementing trunk optical fiber protection in EPON. According to the technical scheme of the present invention, activating an optical module at a master PON port, deactivating an optical module at a standby PON port, configuring a service for the master PON port, and synchronizing static data and dynamic data to the standby PON port; synchronizing and adjusting a value of an MPCP counter at the standby PON port according to a value of an MPCP counter at the master PON port; and carrying out fault detection, transmitting an operating state to the standby PON port when the fault occurs, and performing a master-standby switch of the PON ports.

Abstract: The present invention discloses a Wavelength Division Multiplexing Filter which can satisfy coexistence requirements of different PON systems and an optical line detecting system.

Abstract: N optical transceivers are each connected to a respective electronic module in one-to-one relation such that a respective one electronic module controls a respective one optical transceiver. An electronic switch matrix provides cross-connect capability between the P redundant electronic modules and N electronic modules to the N optical transceivers. A system controller determines when an active N electronic module has failed, and configures the electronic switch matrix to switch a P redundant electronic module into the optical transceiver to which the failed electronic module was connected. A system switch module redirects traffic and routing information, under the direction of the system controller, from the failed module to the newly activated redundant module so that the redundant module assumes the functionality of the failed module.

Abstract: A detection device is electrically connected to a controlled device through a power line and configured for detecting a power condition of the controlled device. The detection device at least includes a power detection module, a processing unit, and an infrared transmitter. The power detection module is configured for detecting an input current transmitted through the power line from the controlled device and converting the input current to an output voltage signal. The processing unit is configured for receiving the output voltage signal and determining the power condition of the controlled device based on a voltage level of the output voltage signal. The infrared transmitter is configured for transmitting an infrared signal based on the determined result of the processing unit to switch the controlled device such that the controlled device performs a corresponding operation. Further, a detecting method is also disclosed.

Abstract: The mode of operation in which a port is configured to operate may be selected so that the manner in which the port will interpret a loss of signal on a receive fiber may be specified. In an immediate mode, the port will interpret a loss of signal on a receive fiber as an indication of a fault on the transmit fiber (or interfaces associated with the transmit fiber) and will immediately shut its transmit interface down. In a multiple cycle detection mode, the port will not immediately interpret a loss of signal on a receive fiber as an indication of a fault on the transmit fiber, but rather will begin monitoring the receive fiber to look for a specified loss of signal pattern on the receive fiber. In this mode the port will interpret a repetitive loss of signal on the receive fiber as an indication of a fault on the transmit fiber. By providing a mode selector, the manner in which the ports are configured to operate may be adjusted individually, as a group, or globally.

Abstract: An optical communications system includes a MSAP and an optical transceiver mounted at the MSAP that communicates over an optical network to at least one optical network terminal (ONT). A first electronic module is operatively connected to the optical transceiver and configured to control the optical transceiver and mounted at the MSAP separate from the optical transceiver. A redundant second electronic module is supported within the MSAP and mounted separate from the optical transceiver. A Mux/Demux module interconnects and supports the first and second electronic modules to form an integral unit and mounted at the MSAP separate from the optical transceiver. The Mux/Demux module is configured to switch the second electronic module into communication with the optical transceiver upon failure of the first electronic module.

Abstract: A fault detection method includes collecting operational parameters of the optical network, collecting information about the structure of the optical network, providing diagnosis outputs by a diagnosis engine analyzing the structure information and the operational parameters, and deriving optical network faults from the diagnosis outputs. The collected operational parameters and the collected structure information may be stored in a database. The operational parameters are related to equipment, Quality-of-Service and/or architecture of the optical network. The optical network faults derived from the diagnosis outputs may concern equipment issues, interoperability problems and/or physical defects. The diagnosis engine generates the diagnosis outputs by using decision trees, Bayesian network techniques and/or multivariate classification techniques.

Abstract: An optical communication system includes an optical transmission terminal including a first transmitter for transmitting an optical signal, and a second transmitter for transmitting information that indicates the first transmitter transmitting the optical signal; and an optical receiving terminal including an optical receiver for receiving the optical signal and the information transmitted from the first and second transmitter, respectively, a storage device for storing a power value of the optical signal monitored in response to receipt of the information transmitted from the second transmitter, and a fault detector for detecting fault of the optical signal by continuously monitoring a power value of the optical signal received by the optical receiver in comparison with the power value stored in the storage device.

Abstract: A network device relating to a digital subscriber line (DSL) such as an asymmetrical DSL (ADSL) or a very high bit rate DSL (VDSL) is provided. In the present invention, the capacitors equipped into the network device are separated and grouped into two independent groups. When the network device runs out of power, the energy of one of the two independent groups is provided for generating the dying gasp signal, and the energy of the other of the two independent groups is provided for amplifying and transmitting the dying gasp signal to a Central Office (CO). Accordingly, the CO can be accurately known whether the network device runs out of power or not, and the respective capacitances of the two independent groups can be significantly reduced so as to reduce the cost of the network device.

Abstract: The present invention relates to a method of and apparatus for evaluating the position of a time-varying disturbance on an optical waveguide. The steps include: transmitting sensing signals onto the optical waveguide, which sensing signals have imposed thereon a modulation which is dependent, at least in part, on their time of transmission; receiving returned sensing signals, which signals have been exposed to the disturbance; and, from the previously imposed modulation on the returned sensing signals, evaluating the position of the disturbance. Because the sensing signals have a modulation that is dependent at least in part on their transmission time, the round-trip time for the signals to travel to and from a disturbance can be inferred. From this round trip time, or a value related thereto, it is possible to directly or indirectly evaluate the position of the disturbance.

Abstract: A method and system for identifying faults in a passive optical network (PON). The method comprises acquiring at an optical network terminal of the PON at least one parameter indicative of at least one malfunction in at least one optical network unit of the PON, and identifying each malfunction from the at least one parameter. The parameters measured include, for each ONU, laser power, sync-lock and -unlock time and bit error rates. The information at the OLT is acquired remotely and in digital form, without use of any physical probing of any point or element in the PON. The system includes a temporal measurement module and a power laser measurement module coupled to a central processing unit that can extract fault information from digital data processed in the two modules.

Abstract: Methods, systems, and computer-readable media provide for notifying an optical line termination (OLT) of a power failure. According to embodiments, a method for notifying an OLT of a power failure is provided. According to the method, a notification of a power failure at an optical network termination (ONT) is received. In response to receiving the notification, power is retrieved from a dedicated power storage unit dedicated to providing power for the transmission of a dying gasp alarm. The dying gasp alarm is transmitted to the OLT utilizing at least a portion of the power from the dedicated power storage unit. The dying gasp alarm notifies the OLT of the power failure.

Abstract: In an OTN (Optical Transport Network), an OTN interface of a network element may receive a BDI (Backwards Defect Indicator) signal from a far end network element to which OTN frames are being transmitted. A BDI signal indicates the occurrence of a unidirectional failure in the transmission of OTN frames to which the far end network element responds by switching its routing to the network element. The OTN interface generates an AIS (Alarm Indication Signal) for its network element so that the network element switches network communication channels to the far end network element to ensure bidirectional switching upon a unidirectional failure.

Abstract: An optical and/or optoelectrical transceiver and system are disclosed that enable parallel transmission of data and management signals via an optical fiber without affecting data signal transmissions transmitted on the optical fiber. Furthermore, the present transceiver and system provide a fault diagnosis function for an optical fiber link. The transceiver and system generally comprise an interface, an intersecting transmission management unit, a driver, a management signal driving unit, an optical transmitter, an optical receiver, an amplifier, a management signal recovery unit, a management unit, and optionally, a power supply unit.

Abstract: The present invention is related to a front-end circuit for an optical communication system including a laser module arranged for transmitting bursts of data signals over an optical network and a driving circuit for providing the bursts of data signals to the laser module. The front-end circuit further includes receiver means in connection with said laser module and arranged for receiving from the optical network optical echo signals. The laser module includes a laser diode arranged for transmitting the bursts of data signals. The driving circuit is arranged for setting a disabling signal for stopping the laser diode from transmitting bursts of the data signals. Fiber-related information can be extracted from the echo signals, such as distance-resolved optical fiber reflections and fiber attenuation.

Abstract: The present disclosure relates to a passive optical network (PON) and provides a method for maintaining the PON, the optical network unit (ONU), and the optical line terminal (OLT) to solve the problem of the ONU being in a constant light emitting state. The method of the present disclosure allows the OLT to determine whether the continuous seizure time of an upstream channel exceeds the preset threshold, and if so, detect the failed ONU that continuously seizes the upstream channel and use a control message or control signal to instruct the failed ONU to turn off power supply to its transmitting circuit.

Abstract: The technique for improving the efficiency in use of power resources while maintaining the received signal quality that satisfies the requirement during a system operation is disclosed. The frame processing apparatus disclosed in the present case includes: a frame processing unit which performs frame processing on an input signal in the designated error processing mode; and a controlling unit which receives the monitoring result relating to the signal quality of the input signal and performs switching control of the designation of the above error processing mode in the frame processing unit based on the received monitoring result.

Abstract: A computerized system and method for managing a passive optical network (PON) is disclosed. The system includes a detection and analysis module adapted for receiving uploaded measurement data from an optical line terminal (OLT) and at least one optical network terminal (ONT), and at least one of technical tools data, service failure data, and outside plant data. The detection and analysis module is adapted for determining a source of failure or potential failure in the PON by correlating the uploaded measurement data and the at least one of technical tools data and service failure data with information stored in a memory medium for the OLT and each ONT.

Abstract: The invention relates to a network comprising at least one host device having an interface card connected to a backplane of said host device, wherein said interface card comprises at least one cage for receiving a pluggable module which performs a traffic management of data transported via at least one optical fiber connected to said pluggable module.

Abstract: A method of monitoring (200) an optical fiber comprises modulating (210) an optical signal with a traffic signal; modulating (220) the optical signal with an incoherent optical frequency domain reflectometry, IOFDR, test signal; transmitting (230) the doubly modulated optical signal onto an optical fiber at a first end of the fiber; detecting (240) scattered radiation output from the first end of the fiber; and analyzing (250) the detected scattered radiation using incoherent optical frequency domain reflectometry to determine a distance to a break in the optical fiber. Apparatus suitable for carrying out the method is also described, as well as an optical communications network employing the method.

Abstract: A transmission device includes a transponder including an oscillator configured to oscillate a local optical laser, a wavelength controller configured to control an oscillation wavelength of the local optical laser to receive desired input signal light, and a coherent receiver configured to combine and detect the local optical laser and input signal light. A controller is configured to control the oscillation wavelength using a wavelength of the input signal light detected by the coherent receiver, to determine an erroneous connection of a signal line related to the input signal light, when the wavelength of the input signal light is not an expected wavelength.

Abstract: A visible light communication (VLC) device is provided for use in a VLC system. The VLC device detect a trigger condition indicating a failure of a VLC link associated with first allocated resources used to communicate with a second VLC device. In response to the detection, the VLC device terminates on the first allocated resources transmission of data to the second VLC device and transmits a fast link recovery (FLR) signal using the first allocated resources. The VLC device receives a fast link recovery response (FLR RSP) signal indicating the second VLC device received the FLR signal and, in response, the VLC device resumes transmission of data to the second VLC device.