Abstract: Embodiments of present system encompass: a plurality of laser sources that produce a plurality of respectively different optical wavelengths; a matrix switch having a plurality of inputs operatively coupled to the plurality of laser sources, each of the plurality of inputs receiving a respective optical wavelength; and the matrix switch having an output that produces a series of interleaved pulses of the different optical wavelengths.

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 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 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: The invention relates to an optical ring network comprising stations (340) which are connected to at least one optical fiber by means of optical couplers, the two ends of the optical fiber being connected to a point of presence or an optical network access node. The point of presence comprises (k) at least an optical emitter (330-1) which emits a falling optical signal having at lest one first wavelength (420) in the direction of one end of the optical fibers (455) and (ii) at least one optical receiver (330-2) which receives a rising optical signal having at least one second wavelength which is different form the first wavelength. The aforementioned optical network access node comprises means such as a hub (320) which can be used for the communication between the optical receiver (330-2) and the optical emitter (330-1). The wavelengths of the rising signals and the wavelengths of the falling signals are shared by several stations.

Abstract: A method for optical supervisory signaling includes determining a wavelength channel status (WCS) value, a wavelength channel failure (WCF) value, and a wavelength channel lit (WCL) value for each one of multiple data channels services by an optical communication node. The method further includes communicating the values to a second optical communication node.

Abstract: A node is provided in an optical communications network that utilizes a first set of add/drop filter elements for extracting and combining optical signals that are carried on wavelength division multiplexed channels in a first wavelength band. Additionally, an extraction element and a combining element for dropping and adding a service channel associated with the wavelength division multiplexed channels. The extraction element is arranged downstream of the add/drop filter elements. The extraction and combining elements are additionally adapted to drop and add, respectively, at least one further wavelength band carrying at least one optical traffic data channel.

Abstract: A pilot tone generator receives optical energy from an optical communication medium carrying a plurality of optical signals. Each optical signal carries data modulated at a unique wavelength and further modulated with a unique identification signal. The identification signal has an amplitude corresponding to an optical power of the associated optical signal. The pilot tone receiver detects each identification signal from the optical energy received and determines its corresponding amplitude. The pilot tone receiver calculates the optical power of each optical signal in the optical energy in response to the amplitude of the associated identification signal.

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: A passive optical arrangement for indicating the presence of a change in ownership along a fiber optic cable span uses an attenuation unit at a splice location that will severely attenuate an optical signal propagating along the span at a predetermined “marker” wavelength. Particularly well-suited in combination with determining the physical location of a fault along a fiber optic cable, the arrangement allows a technician to use an OTDR at the marker wavelength to determine both the physical location of the fault as well as the physical location of a change in ownership (if any) between the technician and the fault location, since the presence of the attenuation unit will register as a large step-wise change in signal propagation.

Abstract: A method for providing voice communications at an optical amplifier site of a DWDM system is disclosed. The method generally comprises receiving an optical service channel at the amplifier site and converting an optical signal of the optical service channel to a digital electrical signal at the amplifier site. The optical service channel carries voice data and has a wavelength that is out of band with respect to wavelength bands of a multiplexed payload channel of the DWDM system. The method further includes sending the digital electrical signal to a router configured to support voice over IP.

Abstract: A main optical signal is wavelength-multiplexed with an optical identifier which is different in wavelength from this main optical signal, before a wavelength-demultiplexing is take place at a desired point so as to isolate the optical identifier from the main optical signal for the purpose of monitoring establishment of correct or incorrect transmission route between transmission and receiving sides based on the detected optical identifier with reference to the stored corresponding data to the relationship between the main optical signal and the optical identifier which belongs to the main optical signal, wherein the monitoring is made without any photoelectric conversion of the main optical signal and any deterioration in quality of the main optical signal.

Abstract: An apparatus and method for processing a supervisory signal for optical network applications. The apparatus includes a subcarrier transmission system configured to receive a first supervisory signal and output a second supervisory signal, and an electrical-to-optical conversion system configured to receive the second supervisory signal and a first data signal and output a first optical signal. Additionally, the apparatus includes an optical-to-electrical conversion system configured to receive the first optical signal and output a first electrical signal and a second data signal, and a subcarrier reception system configured to receive the first electrical signal and output a third supervisory signal. The second supervisory signal is associated with a first subcarrier frequency. The first data signal is associated with a first data bandwidth, and the first data bandwidth includes a first data frequency. A ratio of the first subcarrier frequency to the first data frequency ranges from 0.8 to 1.

Abstract: An optical transmission system having a supervisory system of devices disposed along an optical link. Counter-propagating Raman amplifiers are disposed along the optical link. Low-frequency supervisory signals are superimposed on the optical signals traveling on the optical link by suitable modulators in the devices disposed along the line. Counter-propagating Raman amplifiers amplify optical signals and do not introduce a substantial amount of attenuation on the low-frequency supervisory signals.

Abstract: An optical transmission system having a supervisory system of devices disposed along an optical link. Co-propagating Raman amplifiers are disposed along the optical link. Low frequency supervisory signals are superimposed on the optical signals traveling on the optical link by suitable modulators in the devices disposed along the line or by the same co-propagating Raman amplifiers. Regeneration of the supervisory signal is provided in at least one device disposed along the optical link in order to counteract attenuation introduced on the supervisory signal by the co-propagating Raman amplifiers.

Abstract: The invention concerns a transmitter-receiver device (A, B) which comprises a receiver unit (RXA) arranged to receive light and optical signals from a transmitter unit (TXA) arranged to transmit light and optical signals. The device also comprises a supervising unit (CUA) which prevents the transmitter unit (TXA) from continuously transmitting light when the supervising unit (CUA) detects that the receiver unit (RXA) does not receive light. The supervising unit (CUA) is arranged to, when it detects that the receiver unit (RXA) does not receive light, change to a test mode where the transmitter unit (TXA) is controlled to intermittently transmit short light pulses the supervising unit has an output (109) where a status signal indicates whether the transmitter-receiver device is in said test mode. The invention also concerns a communication system which comprising at least two such transmitter-receiver devices.

Abstract: The invention concerns a transmitter-receiver device (A, B) which comprises a receiver unit (RXA) for receiving optical signals and transmitter unit (TXA) for transmitting optical signals. Furthermore, the transmitter-receiver device (A, B) comprises a supervising unit (CUA) which supervises the functions of the receiver unit (RXA) and the transmitter unit (TXA). Furthermore, the transmitter-receiver device (A, B) comprises a transmitter circuit which transmits optical communication signals in response to a balanced electric input signal. The invention also concerns a communication system comprising two transmitter-receiver devices (A, B). Through the structure of the invention is by relatively simple means a well functioning device achieved, which, inter alia, makes it possible to supervise the status of the two transmitter-receiver devices (A, B) in an advantageous manner.

Abstract: An optical transmission apparatus, an optical repeater using the optical transmission apparatus, and an optical cross-connect equipment for controlling switches depending on supervisory information, comprising: a doped fiber for amplifying an optical signal of wavelength ?d; a wavelength multiplexer for outputting a pumping light to the doped fiber; a wavelength multiplexer for multiplexing an amplified optical signal and a supervisory optical signal to as to output it to an optical fiber at downstream side; a pumping and supervisory light source; an optical coupler for distributing the light from the light source at a ratio of N:1 to the wavelength multiplexers; and a driver for controlling the light source by adding the supervisory information and a direct current signal.

Abstract: An instrument for measuring bidirectional optical signals propagating in an optical transmission path between elements one of which will not transmit if continuity of the transmission path is not maintained, for example a branch path between a central offices optical line terminal (OLT) and an end-user's optical network terminal (ONT), comprises first and second connector receptacles for connecting the instrument into the path, a 2×2 coupler (32) having first and second ports (28, 30) connected to the first and second connectors (22, 24), respectively, for completing the optical transmission path, a third port (36) for, outputting a portion of each optical signal received via the first port (28) and a fourth port (34) for outputting a portion of each optical signal received via the second port (30) Detectors (38, 42, 44) coupled to the third and fourth ports convert the optical signal portions into corresponding electrical signals, which are processed to provide the desired measurements.

Abstract: A method, a system and a module are proposed for detecting and locating faults in an optical multi channel network composed of network nodes. The method includes assigning different sub-carrier pilot tones to a number of the nodes comprising Network Elements (NE), applying the different sub-carrier pilot tones to any signal added to the network via the respective nodes, checking presence of one or more of the sub-carrier pilot tones at one or more points of the network, and, based on results of the checking, locating a faulty section of the network in case a fault occurred.

Abstract: A method and apparatus for controlling the pump powers of a broadband DWDM optical system using Raman amplification which determines pump settings that are advantageously directed to minimizing the peak-to-peak ripple of the channel powers with respect to a given per-channel target. The illustrative method and apparatus first formulates a linear programming optimization problem, and then solves the formulated linear program in order to derive a new set of pump powers to be applied to the Raman amplification pumps. In accordance with the principles of the invention, the formulated linear programming optimization problem advantageously includes one or more “virtual” channels in addition to the actual channels used in the optical transmission system. The linear program may be solved with use of any conventional linear programming solution technique, such as, for example, the simplex method.

Abstract: An optical transmission system accomplishes optical transmission over a long distance by combining a multiplexing line terminal with optical amplifiers, linear repeaters, and regenerators with optical amplifiers combined together. The system also accomplishes the optical transmission over a short distance by directly connecting the linear terminals therebetween, with an electric-to-optic converter replaced by an electric-to-optic converter having a semiconductor amplifier, with an optic-toelectric converter by an optic-to-electric converter having an avalanche photodiode as light receiver, and with no use of any optical booster amplifier and optical preamplifier in multiplexing line terminal. With these, the optical transmission system can be easily constructed depending on the transmission distance required.

Abstract: A system and method for a transparent WDM metro ring architecture in which optics enables simultaneous provisioning of dedicated wavelengths for high-end user terminals, while low-end user terminals share wavelengths on “virtual rings”. All wavelengths are sourced by the network and remotely modulated at customer “End Stations” by low cost semiconductor optical amplifiers, which also serve as transmission amplifiers. The transparent WDM metro ring architecture permits the communication of information and comprises a fiber optical feeder ring, at least one fiber optical distribution ring, a network node (NN), at least one access node (AN) said network node and said at least one access node connected via said fiber optical feeder ring and at least one end station (ES) connected via said fiber optical distribution ring to said at least one access node, wherein said user is attached to said at least one end station.

Abstract: Method and apparatus for implementing optical supervisory channel using broadband noise modulation are described. One embodiment of the present invention is a system for transmitting a supervisory channel from an optical fiber amplifier. The system comprises a first stage amplifier and a noise modulator module. The noise modulator module includes an erbium-doped fiber (“EDF”) that receives a pump for exciting the EDF and emits an amplified noise signal and a modulator that modulates the amplified noise signal with a supervisory signal, wherein the modulated noise signal is input back into the first stage amplifier.

Abstract: An optical repeating system includes an optical transmitter and a plurality of optical amplifying repeaters. The optical transmitter specifies a part or all of the optical amplifying repeaters, and transmits a supervisory command to the specified optical amplifying repeaters as a first sub-signal via an uplink or downlink optical transmission line. The supervisory command is a command to supervise internal circuits of the optical amplifying repeaters. Receiving the supervisory command addressed thereto via the uplink or downlink optical transmission line, the optical amplifying repeaters each transmit a supervisory signal indicating a supervisory result corresponding to the supervisory command to optical receivers via the uplink and downlink optical transmission lines as a second sub-signal. The optical system can reduce the time take to acquire the supervisory information about the plurality of the optical amplifying repeaters.

Abstract: A system and method for improving the transmission quality of a WDM optical communications system begins by determining the bit-error rate for an optical channel before forward error correction is performed at a receiver. The pre-corrective bit-error rate is fed back through a feed back circuit that includes a parameter adjustment module which adjusts an optical signal parameter based on the bit-error rate. As examples, the signal parameter may be a channel power, dispersion, signal wavelength, the chirp or eye shape of an optical signal. The feedback circuit may also adjust various parameters within the WDM system, including amplifier gain, attenuation, and power for one or more channels in the system. By adjusting these parameters based on a pre-corrective bit-error rate, transmission quality is improved and costs are lowered through a reduction in hardware.

Abstract: A network management communication infrastructure is provided that supports in-fiber signaling amongst the network components residing in an optical transport network. The network management communication infrastructure introduces an optical media management channel into each of the optical fibers that resides in an optical transport network.

Abstract: Disclosed herein is a signal transmission method in a wavelength-division-multiplex (WDM) transmission system. The WDM transmission system comprises a first WDM terminal for transmitting a WDM signal, a second WDM terminal for receiving the WDM signal, and an optical add-drop multiplexer (OADM) node for transmitting to a network element an optical signal of a specific wavelength of the WDM signal which is transmitted between the first and second WDM terminals. The WDM signal is transmitted from the first WDM terminal to the second WDM terminal regardless of whether an optical signal is added or dropped at the OADM node. The network element employs an optical signal of an idle wavelength of the WDM signal that has no transmission data, to transmit another transmission data that is transmitted by the network element.

Abstract: A wavelength-division multiplexed optical transmission system to keep the correlation of data patterns among wavelength channels to the low level, preventing large XPM and XGM from occurring when the correlation is strong, and assuring a stable transmitting quality.

Abstract: A transmitter for optical communication systems includes a source of optical radiation, a source of complex non-information signals, and a modulator unit in communication with the source of optical radiation. The modulator unit is also in communication with the source of complex non-information signals. The modulator has an input adapted to receive information-bearing signals.

Abstract: An optical communication equipment comprises shared optical sources 88a–88d to be shared by communication nodes 100a–100d, the wavelengths of optical signals 76a–76d are converted into desired wavelengths ?a–?d according to the addressed information of the corresponding optical label signals 77a–77d by using the shared optical sources 88a–88d, and routed to the addressed communication nodes without being converted into electrical signals by using the wavelength routing function of the cyclic-wavelength arrayed-waveguide grating (AWG) 120. The load of each communication node can be reduced by incorporating the multi-wavelength optical sources, which can be shared among individual communication nodes, into the router 80.

Abstract: An optical communication equipment comprises shared optical sources 88a–88d to be shared by communication nodes 100a–100d, the wavelengths of optical signals 76a–76d are converted into desired wavelengths ?a–?d according to the addressed information of the corresponding optical label signals 77a–77d by using the shared optical sources 88a–88d, and routed to the addressed communication nodes without being converted into electrical signals by using the wavelength routing function of the cyclic-wavelength arrayed-waveguide grating (AWG) 120. The load of each communication node can be reduced by incorporating the multi-wavelength optical sources, which can be shared among individual communication nodes, into the router 80.

Abstract: In networks carrying existing optical traffic on one wavelength band in combination with wavelength division multiplexed traffic carried on a second wavelength band, there is a need to enable processing of the two systems without subjecting the WDM channels to unacceptable losses. The invention meets the above need by the provision of a node in an optical communications network that has a first set of add/drop filter elements for extracting and combining optical signals carried on wavelength division multiplexed channels in a first wavelength band and an extraction element and combining element for dropping and adding, respectively, a service channel associated with the wavelength division multiplexed channels. The extraction element is arranged upstream of the add/drop filter elements relative to the direction of traffic flow and the combining element is arranged downstream of the add/drop filter elements.

Abstract: A wavelength division multiplex transmission system with substantial functions for avoidance of defects is provided. The system comprises an optical transmission device and an optical receiving device. The optical transmission device comprises an operating-system optical transmission unit and a standby-system optical transmission unit, and distributes transmission signals to be transmitted among a plurality of wavelength components, converts the signals into WDM signals, and transmits the WDM signals to a WDM transmission network. The optical receiving device comprises an operating-system optical receiving unit and a standby-system optical receiving unit, and restores WDM signals from the WDM transmission network into transmission signals.

Abstract: An optical transmission system capable of monitoring the operating status of Raman-amplifier repeaters even when an optical transmission line is partly disrupted by a fiber failure. An end station sends a monitoring command signal to request a particular repeater to report its operating status, together with a response carrier wave for use in that reporting. With their different wavelengths, an upstream wavelength selector in the repeater selectively passes the monitoring command signal while reflecting back the response carrier wave. Responsive to the command, a monitoring controller creates a response message containing operating status information. An excitation unit performs Raman amplification with a pump beam modulated by a modulation controller, so that the response message be superimposed on the response carrier wave propagating on the upstream link.

Abstract: The present invention provides an optical wavelength multiplexing transmission apparatus and an optical output control method for an optical wavelength multiplexing transmission apparatus in an optical wavelength multiplexing transmission system using a main signal light and an OSC light. The optical wavelength multiplexing transmission apparatus (10a) is made up of a first transmitting/receiving section (52a) a second transmitting/receiving section (52b) and an apparatus supervisory control unit (54). This can not only achieve quick restoration from troubles, but also stably calculate an optical output level even if a change of the number of wavelengths to be multiplexed takes place in a main signal light, and even save troublesome adjustments for the improvement of reliability of a transmission line while eliminating the need for a signal source for the adjustment of a receive optical level at the initial installation.

Abstract: A pilot tone generator receives optical energy from an optical communication medium carrying a plurality of optical signals. Each optical signal carries data modulated at a unique wavelength and further modulated with a unique identification signal. The identification signal has an amplitude corresponding to an optical power of the associated optical signal. The pilot tone receiver detects each identification signal from the optical energy received and determines its corresponding amplitude. The pilot tone receiver calculates the optical power of each optical signal in the optical energy in response to the amplitude of the associated identification signal.

Abstract: An optical fiber propagates and amplifies a second signal light that is a wavelength-multiplexed signal of a first signal light of a plurality of wavelengths and a reference light that is out of a wavelength range of amplification. An excitation light source outputs an excitation light for amplifying the second signal light. A beam splitter splits a portion of the second signal light into the first signal light and the reference light. A signal light level detecting unit detects a level of the first signal light. A reference light level detecting unit detects a level of the reference light. A signal level setting unit calculates a target value for constantly maintaining a Raman gain, and controls the output level of the excitation light in such a way that the first signal level matches with the target value.

Abstract: There is defined an optical link section which leads from output interfaces of an optical switch equipment to the input interfaces of an optical switch equipment. In-band control channels for every optical links are interposed between the optical switch equipments and an optical multiplex section. The in-band control channels exchanges the optical link attributes specified by the interfaces of the optical switch equipments and the optical link attributes specified by the optical multiplex section, mutually as control messages.

Abstract: A communication system performs WDM optical communications efficiently with variably set supervisory control channels. The communication system includes a supervisory control channel setting unit for variably setting supervisory control channels for supervising optical communications, said supervisory control channels including a first optical supervisory channel whose transmission band falls outside of the transmission band for main optical signals, and a second supervisory channel whose transmission band falls in an idle band in the transmission band for said main optical signals. The communication system also has a WDM transmitting unit for wavelength-multiplexing and -demultiplexing said supervisory control channels and said main optical signals. A setting information indicating unit indicates, to a WDM device, setting information for setting the supervisory control channels. An operating state managing unit manages a network operating state.

Abstract: An exemplary embodiment of the invention is a dispersion compensation module for compensating dispersion in a communications network. The dispersion compensation module includes dispersion compensating fiber having a dispersion coefficient that varies with wavelength. A thermal regulator adjusts the temperature of the dispersion compensating fiber to adjust the dispersion characteristic of the dispersion compensating fiber. Alternate embodiments of the invention include a communications system using the dispersion compensation module and a method for compensating dispersion.

Abstract: A handheld optical unit is disclosed to measure optical characteristics of an optical input. A personal digital assistant is mounted to a housing to serve as a host computer for an optical spectrum analyzer disposed within the housing.

Abstract: An optical communication system for optically transmitting transmission data from a transmitting station to a transmitting device includes an adder for adding an intermediate frequency subcarrier signal modulated with data to be transmitted to a pilot carrier signal as a sinusoidal wave, and an electro-optical converter for electro-optically converting the above sum signal to an optical signal by directly modulating a semiconductor laser element having a resonant frequency fr in accordance with the sum signal and transmitting the signal to an optical fiber for a down link. The frequency fIF of the intermediate frequency subcarrier signal and the frequency fLO of the pilot carrier signal satisfy fLO?fIF?1[GHz], 2×fIF<fLO<(?)×fr, fIF<1[GHz], and 2 [GHz]<fLO.

Abstract: An optical transmission system including at least one optical transmitter configured to transmit at least one signal wavelength and a tuning wavelength, an optical receiver including an optical filter having a filter bandwidth including the at least one signal wavelength and a percentage of the tuning wavelength and an optical to electrical signal converter configured to receive the at least one signal wavelength from said filter, a first tuning optical to electrical converter configured to receive a first portion of the tuning wavelength stopped by said filter, a second tuning optical to electrical converter configured to receive a second portion of the tuning wavelength passed by said filter, and a filter controller configured to tune the filter bandwidth based on the relative proportion of first and second portions of the tuning wavelength provided to the first and second tuning optical to electrical converters.

Abstract: The control of the transmission of useful optical signals on different line paths of an optical transmission device is accomplished via at least one of the following features: using signal sources and signal sinks, the useful optical signals are coupled into the line paths, or are coupled out of them; at least one portion of the optical line paths is configured as normal line paths having coupling nodes via which a switchover to an alternative line path can be undertaken if a normal line path is disturbed; in addition to the useful optical signals, test signals, whose evaluation is used for the switchover between the line paths, are transmitted bidirectionally section-by-section; at least two types of test signals can be transmitted, of which a first type is used as an indicator for an intact line path and a second type as an indicator for a disturbed line path; and any switchover to an alternative line path is only undertaken if, before the detection of the disturbance, a test signal of the first type has be

Abstract: In an optical network that communicates upstream data utilizing a time division multiple access (TDMA) technique, end nodes transmit upstream data on a first wavelength in accordance with a transmission sequence. The end nodes transmit a timing signal on a second wavelength following the upstream data. The timing signals are reflected by a wavelength selective reflective element to each of the end nodes. The end nodes track the timing signals to determine when to transmit upstream data in accordance with the transmission sequence. The optical network includes an outside plant node coupled to the system head end with a distribution fiber. The outside plant node is coupled to the end nodes with drop fibers. The outside plant node includes a splitter/combiner and the wavelength selective reflective element. The wavelength selective reflective element reflects the timing signals on the second wavelength and passes upstream and downstream data on other wavelengths.

Abstract: A system and method for identifying one or more characteristics of an optical signal, in which a transmitter is operable to transmit an optical signal and a receiving unit is operable to receive the optical signal. The transmitter has a laser for generating the optical signal and an encoding unit adapted to control the laser to activate and deactivate the optical signal during a laser shutdown state based on a predetermined code. The receiving unit has an optical receiver optically coupled to the transmitter by a light transmission medium and is operable to receive the optical signal from the transmitter. The receiving unit also has a decoder measuring at least one of an active time of the optical signal and the inactive time between active times of the optical signal. The decoder determines at least one of the one or more characteristics of the optical system based on at least one of the active time or the inactive time.

Abstract: To automate fiber connectivity management in optical systems, a dedicated low bit-rate communications channel unique to each fiber connection in an optical system is provided. The dedicated communications channel simplifies fiber connectivity management by supporting the exchange of port identification information from one optical component to another after which processing determines if the specific connection is a desired association. The dedicated communications channel supports optical interconnection surveillance for all card-to-card optical connections within a group of related cards or within an optical network link. Automating fiber connectivity management in this manner will enhance future products by simplifying the fiber connection validation process and ensuring that any specific connection between optical components is the required association.

Abstract: An apparatus for transferring monitor signals, which apparatus receives a primary signal, and a secondary signal for monitoring a wavelength, and outputs the primary signal and the modulated secondary signal. The apparatus includes an optical coupler to which the primary signal is input, a first optical branching filter optically connected to a signal output terminal, a first optical amplifier optically connected in series between the optical coupler and the first optical branching filter, and a first optical band-pass filter optically connected in series between the optical coupler and the first optical branching filter, but optically connected in parallel with the first optical amplifier. The primary signal is input into the optical coupler and output from the signal output terminal through the first optical amplifier and the first optical branching filter.