Abstract: Chromatic dispersion compensation is performed in one or more pluggable optical transceiver (POT) devices operating within an intensity-modulated direct-detection (IMDD) optical network. Compensation is performed within each POT using an electrical and/or optical chromatic dispersion module which are controlled by a set of parameters. A network computing device includes a computer processor and a host management interface for communicating with the POT. In the event of a link failure, the computer processor determines a second set of parameters to control the one or more dispersion compensation module(s) of the POT. The second set of parameters are different from a first set of parameters used to control the one or more compensation module(s) in the case of a first optical path. The computer processor causes the POT to use the second set of parameters in place of the first set of parameters.

Abstract: An apparatus for subsea environment sensing. In one aspect, the apparatus may include a repeater assembly, disposed in an optical repeater; and an environmental sensor assembly, disposed proximate to the repeater assembly, the environmental sensor assembly being coupled to receive power from the repeater assembly over an optical link.

Abstract: In some examples, fiber optic cable location may include transmitting a coherent laser pulse into a device under test (DUT). Based on an analysis of reflected light resulting from the transmitted coherent laser pulse, changes in intensity of the reflected light caused by a plurality of signals directed towards the DUT may be determined. Further, based on the changes in intensity of the reflected light, a location of the DUT may be determined.

Abstract: There are provided methods and systems that enable the use of the backscattering pattern produced by an optical fiber in an OTDR trace as a signature (also referred to herein as the “RBS fingerprint”) to recognize an optical fiber. It was found that it may be difficult to obtain repeatable signatures as those are sensitive to the wavelength of the OTDR laser source and the temperature of the fiber. OTDR methods and systems that are adapted to compare the backscattering pattern in a more repeatable manner are therefore provided. Once the repeatability issue is overcome, such signature can be used for identification purposes and enable new applications.

Abstract: A method of obtaining a measure of asymmetry between optical fibers of a forward and reverse paths is provided in order to synchronize clocks of optical nodes connected by asymmetrical optical fiber paths. The method includes receiving, at first and second arrival times, from a first optical network device, a first optical signal transmitted on a first optical fiber and a second optical signal transmitted on a second optical fiber, calculating a first time difference between the second arrival time and the first arrival time. The method includes determining a measure of asymmetry between the first optical fiber and the second optical fiber based on the first time difference and a second time difference between a first time of transmission by the first optical network device of the first optical signal and a second time of transmission by the first optical network device of the second optical signal.

Abstract: A method of obtaining a measure of asymmetry between optical fibers of a forward and reverse paths is provided in order to synchronize clocks of optical nodes connected by asymmetrical optical fiber paths. The method includes receiving, at first and second arrival times, from a first optical network device, a first optical signal transmitted on a first optical fiber and a second optical signal transmitted on a second optical fiber, calculating a first time difference between the second arrival time and the first arrival time. The method includes determining a measure of asymmetry between the first optical fiber and the second optical fiber based on the first time difference and a second time difference between a first time of transmission by the first optical network device of the first optical signal and a second time of transmission by the first optical network device of the second optical signal.

Abstract: A method of optical label swapping implemented by a switch used in a software defined network system that in one embodiment includes providing a 400-Gbit/s payload having a Nyquist shaped carrier in a 75-Ghz bandwidth spacing using a payload generator module controlling at least one first optical laser, and inserting a first optical label adjacent to the payload flow in a remainder of a 100-Ghz bandwidth with a label generator controlling at least one second optical laser. The label generator and the payload generator are controlled by a software defined network (SDN). A package of the payload and the first optical label is transmitted to a receiving node. The optical label can be swapped at the receiving node with a flex grid wavelength selective switch (WSS) controlled by the software defined network.

Abstract: A method of mapping a network path in which a geographic path of cables of a network between a geographic location of a network component and a geographic location of a terminal network element is estimated electronically using walking directions data from a geodata services provider. A geographically accurate street map is populated with the geographic location of the network component, the geographic location of the terminal network element, and the estimated geographic path. The map is capable of being displayed with the use of geospatial software. A signal processing electronic device for populating a display of an interactive graphical user interface with network path mapping information and a non-transitory computer readable storage medium having computer program instructions stored thereon that, when executed by a processor, cause the processor to perform the above referenced operations are also provided.

Abstract: A wavelength shifter module and a method therein for tuning an OTDR signal to at least one pre-selected wavelength in a passive optical network (PON). The wavelength of the OTDR signal is shifted to a pre-selected wavelength to enable a remote node in the optical distribution network ODN of the PON to forward the OTDR signal to a specific drop section in the ODN. The invention also includes a remote node and a method in a remote node for receiving a wavelength shifted OTDR signal having a preselected wavelength and outputting the wavelength shifted OTDR signal to a specific drop section. Furthermore, the invention involves a method for determining the location of a fault section in a drop section.

Abstract: There is provided an optical transceiver apparatus including an optical transmitter configured to transmit light of variable wavelength, an optical receiver configured to receive light generated from an opposite light source, and a controller configured to perform initialization to a wavelength corresponding to when an intensity of light received by the optical receiver is greater than or equal to a reference power, while varying the wavelength of light output by the optical transmitter.

Abstract: An optical communication device comprises an input/output configured to be coupled to an optical communications line, and a passive optical loopback module coupled to the input and configured to receive optical signals from the input/output, the loopback module being further configured to reflect incoming signals of a test wavelength to the input/output.

Abstract: An optical transmission system for optically transmitting information between apparatuses via an optical transmission path. The system includes: a sending unit that emits, to the optical transmission path, excitation light for detecting an inter-apparatus connection via the path; a responding unit that receives the excitation light from the path and emits detection light to the path using light energy of the excitation light; a response receiving unit that receives the detection light from the path and outputs a detection light current; a detecting unit that detects presence/absence of the inter-apparatus connection based on the detection light current; a light signal transmitting unit that emits, to the path, a light signal for optically transmitting the information based on the detection result by the detecting unit; and a light signal receiving unit that receives the light signal from the path.

Abstract: According to an aspect of an embodiment, a method of modulating supervisory data onto an optical signal includes increasing a first power level of a first polarization component of an optical signal based on supervisory data. The method further includes decreasing a second power level of a second polarization component of the optical signal based on the supervisory data. The decrease in the second power level is substantially the same as the increase in the first power level such that a total power of the optical signal is substantially constant.

Abstract: An optical fiber transmission system adapted to provide a remote passive identification of components deployed in said transmission system, wherein each component comprises an associated passive optical identification unit adapted to provide identification of a component type of the respective component on the basis of a received optical identification signature carried in an optical identification signal to said component.

Abstract: An optical network (1) comprising an optical network element (10) comprising a first optical transmitter (14), a first controller (16), a first optical receiver and a second optical receiver and a second optical network element (12). There is provided a transmission path (30) between said first optical network element and said second optical network element. Said first optical transmitter is arranged to generate and transmit a first optical signal. Said first controller is arranged to control said first optical transmitter to generate and transmit said first optical signal at a wavelength selected from a predetermined plurality of wavelengths. Said first optical receiver is arranged to detect a backscatter portion of said first optical signal returned to said first optical network element along said transmission path by distributing scattering.

Abstract: An optical transmission device according to the present invention comprises: a Raman amplification means; a main signal light sending means which sends first main signal light; a communication interruption detection light monitoring means which sends a first signal if it cannot detect communication interruption detection light; a main signal light monitoring means which sends a second signal if it cannot detect second main signal light; a light monitoring signal analysis means which sends a result of its analysis of a light monitoring signal as a third signal in a predetermined period of time; and a control means which makes the Raman amplification means suspend the generation of the excitation light, if it cannot receive the third signal even after the elapse of the predetermined period of time in the state it has received the first signal and has not received the second signal, and stops sending of the first main signal light from the main signal light sending means when receiving the second signal further.

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 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 multi-channel optoelectronic device is configured to establish a redundant status link with a remote device. The optoelectronic device can transmit N transmit optical signals to the remote device over a plurality of transmit channels and receive N receive optical signals from the remote device over a plurality of receive channels. The optoelectronic device includes one or more spare transmit and receive channels. When used with a remote device having spare transmit and receive channels, each device can establish a status link with the other and use the status link to switch out transmit and/or receive channels to identify and permanently switch out the worst transmit and/or receive channels. Alternately, the device can interoperate with a non-status-link enabled remote device by determining that the remote device is not status-link enabled, transitioning to a low transmit power mode, and transmitting and receiving over a plurality of default transmit and receive channels.

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: The invention refers a method and an arrangement for in service Raman gain measurements and monitoring of a wavelength division multiplex system. By measuring the power level values of a transmitted WDM signal (WMS_TX) and an optical supervisory signal (OSS_TX) at the transmitter and the power level values of the received signals (WMS_RX; OSS_RX) the Raman gain can be calculated for the different channels.

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: An optical communication system supporting detection and communication networks. A communication network transmission path and the detection network transmission path are provided as separate paths established by separate fibers or fiber pairs of the same optical fiber cable. All of the elements coupled to the communication network transmission path and the detection network transmission path may be powered by the same power feed equipment through the same optical fiber cable power conductor.

Abstract: A system and method for managing the selection of ghost channels in an optical communication system, including components configured to collect one or more first data values indicating the validity of an optical communication channel within a first degree of a node in the optical communication system, collect one or more second data values indicating the optical power level of the optical communication channel, transmit the first and second data values to a second degree of the node, receive the first and second data values at the first degree, and aggregate the first and second data values for the first degree and the second degree at the first degree.

Abstract: An optical node disposed along a transmission line that uses optical fiber. The optical node includes a first signal generator and a monitor. The first signal generator generates a first measurement signal for measuring polarization mode dispersion values and transmits the first measurement signal along the transmission line. The monitor detects a second measurement signal from the transmission line and measures polarization mode dispersion values by performing signal processing with respect to the second measurement signal.

Abstract: A communication system includes a transmitter that combines and transmits a first signal light and a dummy light having a wavelength different from the first signal light; a first amplifier that amplifies a light transmitted by the transmitter to a constant power; a communication device that separates the dummy light from the light amplified by the first amplifier, has a variable transmittance and allows the separated dummy light to pass through, and combines and transmits the passed dummy light and a second signal light having a wavelength different from the dummy light; a second amplifier that amplifies a light transmitted by the communication device to a constant power; a receiver that receives the second signal light included in the light amplified by the second amplifier; and a controller that controls the transmittance.

Abstract: An optical transmission apparatus is provided with an optical filter on a transmission line between a reception end of a transmission line and an OSC receiver. The optical filter has transmission characteristics such as to pass main signal light and optical supervisory channel light (OSC light), and to cut off noise light contained in at least one end portion band on a short wavelength side and a long wavelength side of an OSC transmission band used for reception of OSC light. By such a configuration, even in a case where the OSC light is Raman amplified and transmitted, the influence of noise light due to Raman amplification can be reduced, and OSC light can be received reliably, enabling high dependability to be realized.

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. A network component comprising at least one processor configured to implement a method comprising detecting an Optical Time Domain Reflectometry (OTDR) signal spectrum that has a modulated pattern, and detecting a reflected OTDR signal spectrum that has a shifted modulated pattern comprising a frequency shift with respect to the OTDR signal spectrum and a time shift proportional to the frequency shift.

Abstract: An optical splitter for a passive optical network for telecommunication signal transmission with an optical line terminal includes a wavelength selective optical electrical converter, an AC/DC splitter, an energy reservoir and optical switches, where the splitter comprises also a data transmission processing module by which the optical switches can be controlled according to data signals transmitted from the optical line terminal.

Abstract: A method for monitoring wavelength-division multiplexed (WDM) signal for detecting signal drift of objective signals, including generation of one or more objective signals and a guard signal. The guard signal has a wavelength that is within a range defined by a guard channel. The first and second objective signals and the guard signal are wavelength-division multiplexed to generate a wavelength-division multiplexed signal. The first objective signal, the second objective signal, and the guard signal are assigned to a first multiplexed objective channel, a second multiplexed objective channel, and a multiplexed guard channel, respectively. The wavelength-division multiplexed signal is received by a monitor and then the error rate of the multiplexed guard channel is determined.

Abstract: A system for mitigating the effects of polarization hole burning in an optical communication system. The system includes an optical input signal comprising one or more traffic channels, a measurement module configured to check for the existence of ghost channels around the traffic channels, and a ghost channel generation module configured to generate a ghost channel around the traffic channels from amplified spontaneous emission noise of the optical input signal.

Abstract: Methods and apparatus for providing distance extension and other transport functions such as error monitoring, provisioning, and link/service management in a fiber channel path are disclosed. According to one aspect of the present invention, a transport node includes a processing arrangement and an output interface. The processing arrangement creates a first ordered set that includes information associated with an ability for the transport node to receive a first fiber channel frame, and inserts the first ordered set between a second ordered set and a third ordered set of a fiber channel stream. The output interface transmits the fiber channel stream, which includes the information regarding whether the transport node is capable of receiving the first fiber channel frame.

Abstract: Consistent with the present disclosure, an optical amplifier is provided that is configurable in one of two modes. In both modes, the optical service channel (OSC) may be dropped and converted to an electrical signal. In the first mode, the electrical signal is subject to further processing and the monitoring and/or control information carried by the OSC may be updated with new data. Such updated monitoring and control information is then supplied to an OSC transmitter and modulated onto an OSC output from the optical amplifier. In a second mode of operation (“loop back” mode), however, the monitoring and/or control information bypasses the processing noted above is looped back to the OSC transmitter unchanged. Accordingly, OSC monitoring and control information or data can be rapidly passed through the optical amplifier with little delay. Moreover, the optical amplifier may be configured to operate in either the first or second modes by appropriately configuring a switch.

Abstract: A system may include a first measurement device configured to be coupled to a first node in an optical path being measured. The first measurement device may be configured to generate a signal at an initiating device; identify an unused channel in an optical path, wherein the optical path includes at least two spans; and transmit the signal on the unused channel. A second test device may be configured to be coupled to a last node in the optical path being measured. The second measurement device may be configured to: receive the signal at a destination device; compensate the signal for chromatic dispersion (CD) and/or polarization mode dispersion (PMD) effects; and determine CD and/or PMD measurements associated with the optical path being measured based on the compensation.

Abstract: The present disclosure provides dynamic performance monitoring systems and methods for optical networks to ascertain optical network health in a flexible and accurate manner. The present invention introduces accurate estimations for optical channel performance characteristics based either on existing channels or with a dynamic optical probe configured to measure characteristics on unequipped wavelengths. Advantageously, the dynamic performance monitoring systems and methods introduce the ability to determine physical layer viability in addition to logical layer viability.

Abstract: A pulse transmission technique is used for wireless communication between a microcomputer (13) having a debugging support circuit (17) and a debugger (13). The pulse transmission technique is based on magnetic field coupling between a first coil (14) provided for the microcomputer and a second coil (8) coupled with the debugger. During an initialization operation, the microcomputer performs a process of configuring a communication condition of the wireless communication to perform the wireless communication. The microcomputer awaits control from the debugger when the microcomputer establishes communication with the debugger. The debugger awaits establishment of the communication and proceeds to control of the microcomputer in accordance with the wireless communication. It is possible to provide contactless interface for system debugging without the need for a large antenna or a large-scale circuit for modulation and demodulation.

Abstract: A fiber output stabilizer according to an aspect of the invention stabilizes output light from a rare-earth doped optical fiber in which at least one kind of a rare-earth element is added to a core. The fiber output stabilizer includes: a monitoring light source that emits monitoring light having a wavelength shorter than that of excitation light exciting the rare-earth element; an optical multiplexer that multiplexes the monitoring light into the excitation light; an optical demultiplexer that demultiplexes the monitoring light passing through the rare-earth doped optical fiber; and a passing light detector that detects light intensity of the monitoring light from the optical demultiplexer.

Abstract: A system for transmitting a plurality of data channels and an optical service channel through an optical fiber link of a Wavelength Division Multiplexed (WDM) optical communications system. The system comprises a first transmitter at a first end of the optical fiber link, for transmitting the data channels as a wavelength division multiplexed optical signal through the optical fiber link in a first direction. A second transmitter is connected at a second end of the optical fiber link, for transmitting the optical service channel through the optical fiber link in a second direction opposite to the first direction.

Abstract: Upon transmission path monitoring, when a monitoring signal responded by one of optical repeaters provided in a main signal transmission path is superposed on an optical main signal and sent out to the main signal transmission path, the optical main signal is branched to optical fibers, that are optical transmission paths, provided separately from the main signal transmission path and each provided with optical repeaters corresponding to the optical repeaters provided in the main signal transmission path, an optical main signal is selected from a desired optical fiber to be monitored from among the optical transmission paths and the monitoring signal is extracted from the optical main signal selected, thereby checking the quality of the desired optical fiber.

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: Embodiments are directed to fiber optic cable diagnostics using digital modulation. A contact of a RFID (radio frequency identification) device located in a cable is connected with a contact of an optical transceiver. Data through the cable is using digital modulation and monitored to determine if the fiber optic cable and the optical transceiver are properly functioning.

Abstract: A network may include fiber optic lines and fiber distribution panels connected by the one or more fiber optic lines. At least one of the fiber distribution panels may include an optical fiber connector designated as a connector that is for emergency use. The network may further include a plurality of optical network terminals located at premises of subscribers to the network.

Abstract: A testing input module for testing an in-service WDM system is provided. The testing input module includes a first light source configured to emit a first light signal to one or more empty channels of the in-service WDM system; and a tunable second light source configured to emit a second light signal to test the one or more empty channels. The testing input module also includes a first switch module configured to: receive from the first light source and output the first light signal during a first time interval; and receive from the second light source and output the second light signal during a second time interval. The second time interval is a duration wherein a channel power monitoring function of the in-service WDM system is not triggered.

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: A system and method for fault identification in optical communication networks. One or more repeaters in the system includes a loop back path that couples an output a first amplifier for amplifying signals carried in a first direction through a repeater to an input of a second amplifier for amplifying signals carried in a second direction through said repeater. Fault analysis is conducted using loop gain data associated with test signals transmitted on the first or second paths and returned on the opposite path through the loop back paths.

Abstract: A method for monitoring wavelength-division multiplexed (WDM) signal for detecting signal drift of objective signals, including generation of one or more objective signals and a guard signal. The guard signal has a wavelength that is within a range defined by a guard channel. The first and second objective signals and the guard signal are wavelength-division multiplexed to generate a wavelength-division multiplexed signal. The first objective signal, the second objective signal, and the guard signal are assigned to a first multiplexed objective channel, a second multiplexed objective channel, and a multiplexed guard channel, respectively. The wavelength-division multiplexed signal is received by a monitor and then the error rate of the multiplexed guard channel is determined.

Abstract: A method for laser safety protection in an optical communication system includes: a downstream station detecting whether an identification signal loaded by an upstream station on a main optical channel in a direction from the upstream station to the downstream station, exist on the main optical channel; if the identification signal is not detected, the downstream station executing a scheduled safety protection procedure. Methods for loading an identification signal on a main optical channel in an optical communication system and an optical amplifier of laser safety protection, which implement loading the identification signal by controlling the change of pump light of optical amplifier or the wave motion of signal light of main optical channel, are also provided. The solution makes it possible to reliably detect a fiber failure when RAMAN amplifiers or remotely-pumped amplifiers exist, thereby implementing laser safety protection.

Abstract: A method and apparatus for distributed measurement of chromatic dispersion in an optical network is disclosed. The network comprises optical switching nodes interconnected by optical links. An optical link may comprise multiple spans, each span ending in a transport module which comprises signal-processing components. At least one optical switching node has a probing signal generator transmitting an optical probing signal along a selected path in the network. Probing-signal detectors placed at selected transport modules determine chromatic-dispersion values and send results to a processing unit which determines appropriate placement of compensators or appropriate adjustments of compensators placed along the path. A preferred probing signal has the form of wavelength modulated optical carrier which is further intensity modulated by a periodic, preferably sinusoidal, probing tone.

Abstract: Various high loss loop back (HLLB) repeater architectures are disclosed that enable selectively monitoring (e.g., measuring, analyzing, etc) of Rayleigh signals from both inbound and outbound directions of an optical communication system. In one such embodiment, first and second optical test signal frequencies (or ranges) are used, in conjunction with selective filtering, for monitoring the outbound and inbound paths, respectively. The repeater architectures allow optical time domain reflectometry (OTDR) monitoring techniques to be employed, for example, in particularly long repeater spans, such as those in excess of 90 km in length.

Abstract: An OTDM-DPSK signal generator includes an optical splitter, a first and a second phase modulator, an optical coupler, and a monitor signal splitter. The optical splitter splits an optical pulse string into a first and a second optical pulse string. The first and second phase modulators generate a first and a second channel DPSK signal, respectively. The DPSK signals are provided with one bit delay to generate another DPSK signal, which enters the optical coupler, which outputs an OTDM-DPSK signal, which enters a monitor signal splitter. The monitor signal splitter splits from the OTDM-DPSK signal a monitor signal and inputs the monitor signal to an optical carrier phase difference detector. The detector generates an optical carrier phase difference detection signal as a function of an optical carrier phase difference between optical pulses. The optical carrier phase difference can thus be detected between optical pulses in an OTDM-DPSK signal.