Abstract: A system and method for simultaneous delivery of a plurality of independent blocks of 500 MHz digital broadcast television services, stacking a plurality of RF blocks on a plurality of spectrally sliced WDM optical bands.

Abstract: An optical access network system having a function of correcting upstream signal waveform distortions occurring in the PON section, wherein a central office side apparatus comprises a main controller to notify each subscriber connection apparatus of a transmission grant period, an equalizer of a tap gain adaptive control type to correct waveform distortions of signals received from the subscriber connection apparatuses, an equalizer controller, and a parameter table for storing, for each subscriber connection apparatus, the initial values of tap gains to be set for the equalizer. The main controller issues a switchover request for switching the equalization characteristic to the equalizer controller each time notifying a subscriber connection apparatus of a transmission grant period, and the equalizer controller retrieves the initial values of the tap gains for the subscriber connection apparatus from the parameter table in response to the switchover request, and sets these values to the equalizer.

Abstract: A method for transmitting traffic in an optical network includes establishing a light-trail in the optical network between a number of nodes. The light-trail couples the nodes and is associated with one of a number of wavelengths in the network. The method also includes, at one or more of the nodes, receiving traffic from one or more client devices of the node to be communicated over the light-trail to a destination node and determining one or more service types associated with the received traffic. Furthermore, the method includes determining traffic shaping information for each service type based on information relating to the arrival of traffic associated with the service type at the node. The traffic shaping information indicating to the destination node the rate at which the traffic associated with each service type should be communicated from the destination node to one or more client devices of the destination node.

Abstract: An optical communication system including a plurality of transceiver ports each including a transmitter configured to produce a downstream MLM-spectrum signal and a receiver configured to receive an upstream spectrum-sliced signal. The spectrum of the downstream MLM-spectrum signal comprises a plurality of distinct narrow-spectrum peaks each corresponding to a longitudinal mode.

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: This invention provides a new architecture for a communication system between head-ends and end-users which expands bandwidth and reliability of the communication system. A mux-node receives communication signals from a head-end and forwards the received communication signals to one or more mini-fiber nodes. The connection to the head-end is via a small number of optical fibers and the connections to each of the mini-fiber nodes may be via one or more optical fibers that may provide full duplex communication. The head-end may communicate with the mux-node using digital or digital and analog signals. The mini-fiber nodes may combine the signals received from the head-end with loop-back signals used for local media access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and transmitted to the mux-node.

Abstract: A transmitter subsystem generates an optical signal which contains multiple subbands of information. The subbands have different polarizations. For example, in one approach, two or more optical transmitters generate optical signals which have different polarizations. An optical combiner optically combines the optical signals into a composite optical signal for transmission across an optical fiber. In another aspect, each optical transmitter generates an optical signal containing both a lower optical sideband and an upper optical sideband (i.e., a double sideband optical signal). An optical filter selects the upper optical sideband of one optical signal and the lower optical sideband of another optical signal to produce a composite optical signal.

Abstract: In an optical element integrated module, first through n-th optical data signals are externally input to first ports of first through n-th optical circulators and are input to first through n-th optical/optical converters via second ports. The first through n-th optical/optical converters modulate first through n-th optical short pulse trains in accordance with the first through n-th optical data signals. First through n-th modulated optical data signals are input to the second ports of the first through n-th optical circulators and are input to an optical time division multiplexing section. The optical time division multiplexing section generates optical time division multiplexed signals by time division multiplexing the first through n-th modulated optical data signals.

Abstract: An optical wavelength division multiplexing network has a multi-level structure where a plurality of optical network units (ONUs) are connected to a lowest-level network. A node apparatus connected to networks other than the lowest-level network includes (a) passive optical components to branch optical signals from a higher-level network to a lower-level network, and couple optical signals from the lower-level network to the higher-level network, and (b) optical amplifiers for the optical signals. A node apparatus connected to the lowest-level network includes (a) an optical multiplexer/de-multiplexer to de-multiplex optical signals from the higher-level network, selectively output an optical signal to each ONU, and multiplex wave-length specific optical signals from the ONUs into a multiplexed optical signal, and (b) optical amplifiers for the optical signals.

Abstract: A cable television (CATV) distribution system, and a method of forming and using the CATV distribution system. In a first embodiment, a narrowcast optical signal is generated by an uncooled laser and converted by a receiver into a narrowcast electrical signal. In a second embodiment, a narrowcast optical signal generated by an uncooled laser is combined with a broadcast optical signal by an optical coupler at a hub of the CATV distribution system to generate a composite optical signal, which at a CATV node is: split into the broadcast and narrowcast optical components, respectively converted into broadcast and narrowcast electrical components, and combined into a composite electrical signal. In a third embodiment, a narrowcast optical signal is generated by an uncooled laser and then combined with the broadcast optical signal by a single receiver.

Abstract: One embodiment of the present invention provides a system that facilitates dynamic allocation of upstream bandwidth in a passive optical network which includes a central node and at least one remote node. Each remote node is coupled to at least one logical entity, which corresponds to a device or a user, that transmits upstream data to the central node and receives downstream data from the central node. The central node is coupled to an external network outside of the passive optical network through a shared out-going uplink.

Abstract: A method for transmitting a packet in a wireless access network based on a wavelength identification code scheme. The method comprises the steps of connecting n number of RNCs (Radio Network Controllers) to one sub-ring where the “n” is a positive integer, and assigning a unique wavelength to each RNC; identifying a packet to be transmitted between the RNCs located within a same sub-ring using the assigned unique wavelength, and transmitting the packet through an SRC (Sub-Ring Controller); connecting m number of SRCs to one main-ring where the “m” is a positive integer, and assigning a unique wavelength to each SRC; and detaching a wavelength identification code from the packet to be transmitted between the RNCs located within different sub-rings, and transmitting the packet having the encapsulated wavelength identification code through an MRC (Main-Ring Controller).

Abstract: A passive optical network system is disclosed that simultaneously provides both broadcasting service and data service. The passive optical network (PON) amplifies the optical signals for the broadcasting service in an optical amplifier media of the local office by pumping optical signals generated from the central office and provides the optical signals for the broadcasting service to the subscriber terminals. Therefore, the present invention can simultaneously provide broadcasting service and data service for more subscribers without reducing the number of subscribers to the PON. Also, the present invention uses a plurality of optical sources for the data service and the broadcasting service and receives the optical signals generated from the optical sources by using a plurality of optical receivers in the subscriber terminals, and thus can provide a greater amount and variety of data services and broadcasting services.

Abstract: A fiber to the home FTTH network for convergence of broadcasting and communication is disclosed. The network includes: an OLT for receiving and converting a first predetermined number of broadcast signals and an Ethernet signal into a plurality of converted optical signals, combining the converted optical signals into converged optical signals for subsequent transmission by an optical wavelength division multiplexing method; and an optical network unit (ONU) for classifying the optical signal transmitted from the OLT into the first predetermined number of broadcast signals and the Ethernet signal, switching a second predetermined number of broadcasting signals of the first predetermined number of broadcasting signals according to each SIU by channel selection information contained in upstream Ethernet information, and switching the Ethernet signal to be transmitted to the SIU according to each SIU so as to transmit the switched signal.

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: An optical transmitter including a multi-lambda source to output injection light consisting of a plurality of injection wavelengths in channels, a circulator having a first port, a second port, and a third port, the circulator receiving the injection light at the first port, and outputting the received injection light to the second port, and further receiving signal light at the second port, and outputting the received signal light to the third port, an arrayed waveguide grating having a multiplexing port connected to the second port of the circulator, and a plurality of demultiplexing ports, spectrum-slicing injection light received from the circulator at the multiplexing port into a plurality of injection channels, and outputting the injection channels to the demultiplexing ports and further receiving and multiplexing a plurality of signal channels at the demultiplexing ports, into a signal light, and outputting the signal light to the multiplexing port, and a plurality of reflective semiconductor optical a

Abstract: Disclosed is an architecture enabling premium services to be provided over fiber to high-end users/customers. This architecture has a plurality of nodes and a passive optical device inserted prior to one of the nodes. The optical device allows wavelengths provisioned for original service(s) to pass through with minimal loss, while other wavelengths provisioned for the premium services are diverted onto a new fiber. This new fiber may be installed at the time of the upgrade, but, sometimes, dark fiber is available. Dark fiber is fiber that carries no optical signals.

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: A method of controlling behavior of an element in a passive optical network (PON) is provided. The method includes (i) issuing a message from a first PON element to a second PON element to cause the second PON element to enter or maintain a state of upstream communications, the state of upstream communications having an enabled state or a disabled state, (ii) ranging the second PON element by the first PON element if the state of upstream communications of the second PON element is in the enabled state, and (iii) bypassing the ranging of the second PON element if the state of upstream communications of the second PON element is in the disabled state.

Abstract: The present invention provides an optical wavelength-division multiple access system and a corresponding optical network unit. A wavelength band Da (wavelengths ?d1 to ?dn) for downlink optical signals corresponding to the n ONUs, a wavelength band Ua (wavelengths ?u1 to ?un) for uplink optical signals corresponding to the n ONUs, a wavelength band Db (wavelengths ?dn+1 to ?dn+m) for downlink optical signals corresponding to the m ONUs, and a wavelength band Ub (wavelengths ?un+1 to ?un+m) for uplink optical signals corresponding to the m ONUs are set different from one another, the wavelength bands Ua and Ub are set adjacent to each other, and the wavelength bands Ua and Da or the wavelength bands Ub and Db are set adjacent to each other.

Abstract: The network comprises an optical ring link (F) and a concentrator (HUB) that sends via one end of the link “downlink” optical signals carried by respective wavelengths and receives “uplink” optical signals via the other end of the link. The link is divided into a plurality of segments (FS1-FS4) separated by access nodes (AN1-AN3) for receivers (RX) of downlink optical signals and for senders (TX) of uplink optical signals. Each access node comprises coupling means that are not wavelength-selective for coupling the segment on the upstream side of the node to the segment on the downstream side and to the receivers and to couple the senders (TX) to the segment on the downstream side. The downlink optical signals are carried by wavelengths belonging to a set of predefined wavelengths. To optimize the use of spectral resources, a rejection filter (NF) is inserted into a segment to reject a portion of the wavelengths of said set of wavelengths.

Abstract: A method and a protection switching arrangement for protection switching of any one of a plurality of optical signals of a multi-wavelength optical signal from the failure of an optical component is provided. The multi-wavelength optical signal which contains the optical signals is itself rerouted by the use of wavelength agnostic rerouting elements, after which a tunable optical filter is used to obtain from the multi-wavelength optical signal the particular optical signal which would have been affected by the failure. In embodiments of the invention where the failed component is a switching fabric, the multi-wavelength optical signal is rerouted away from the failed switching fabric through a redundant switching fabric after which the particular optical signal is obtained with use of the tunable optical filter.

Abstract: In a PON system by WDM, IP broadcast can be received without oppressing a band used by a user for Internet communication. An OLT provides a first wavelength received in common by respective ONUs and plural second wavelengths by which the OLT and the respective ONUs perform communication individually. With respect to signals in the downstream direction, each of the OLTs includes a transmitter to transmit the first wavelength and plural transmitters to transmit the second wavelengths used for the individual communication with the respective ONUs. Each of the ONUs includes a receiver to receive the first wavelength and a receiver to receive the second wavelength used in the ONU itself. The OLT transmits data of the IP broadcast by the first wavelength and transmits individual data of each of the ONUs by the second wavelength corresponding to the ONU.

Abstract: A passive optical network which employs multiple wavelengths to increase overall system bandwidth, with each wavelength being shared by multiple optical network units (ONUs) according to a time division multiple access (TDMA) protocol. The upstream TDMA traffic therefore includes multiple TDMA data streams at different wavelengths. An optical line terminal (OLT) preferably receives the multiple TDMA data streams and separates them to different detectors before ultimately combining all data into a single data stream using a multiplexer after performing clock and data recovery functions. In this manner, the upstream bandwidth in a passive optical network can be markedly increased without requiring an increase in data transmit speeds, and while using low cost/low speed detectors in the OLT, and low cost/low speed transceivers in the ONUs. System bandwidth can be further improved by using higher cost, higher speed components.

Abstract: One or more overlay wavelengths are applied to a GPON architecture to provide sufficient, cost-effective forward bandwidth per home for targeted, unique narrowcast services to allow traditional HFC operators to use a PON architecture with their existing HFC equipment. A separate return path capability using a separate coaxial cable with RF signals to the GPON may also be used. This return capability may be provided either by a fiber optic link or coaxial link from the home.

Abstract: A termination device for use in a WDM-SCM PON system can effectively support a multi-channel integration function of a WDM/SCM PON system.

Abstract: An Ethernet passive optical network (EPON) ring for providing protection against fiber failures. The optical network unit (ONU) is coupled to the ring fiber by a three-port passive optical splitting module that has three two-way optical passages. By the three two-way optical passages, the OUN receives/transmits data from/to the two ends of the optical line termination (OLT) to provide protection while the fiber failure. Moreover, it provides better authorization of users and simpler collision detection by the two-way transmission of the three-port passive optical splitting module to prevent hackers from invading and to reduce collisions.

Abstract: An optical network terminator of the present invention includes an optical wavelength division multiplexer for receiving an optical signal and incoherent light. An optical detection unit converts a downstream high speed and low speed optical signals into electrical signals. A laser diode converts an upstream signal into an optical signal. A high speed driving unit is supplied with power from a power supply unit to drive a forward-biased laser diode and establish a data and video channel. A high speed reception unit is supplied with the power to receive a downstream data and video channel. A charging unit outputs charged power at the time of a power failure. A low speed driving unit is supplied with the charged power to reverse-bias the laser diode to establish a voice channel. A low speed reception unit is supplied with the charged power to receive a voice channel.

Abstract: A hub for use in a passive optical network (PON) includes a transmission fiber on which an information-bearing optical signal is received, a double-cladded, rare-earth doped fiber located along the transmission fiber for imparting gain to the information-bearing optical signal, and a combiner having an output coupled to the transmission fiber and a plurality of inputs. The output is coupled to the transmission fiber such that optical energy at pump energy wavelengths but not signal wavelengths are communicated therebetween. At least one pump source is optically coupled to one of the inputs of the combiner for providing optical pump energy to the double-cladded, rare-earth doped fiber. An optical splitter is also provided. The optical splitter has an input coupled to the transmission fiber for receiving an amplified, information-bearing optical signal and a plurality of outputs for directing portions of the amplified, information-bearing optical signal to remote nodes in the PON.

Abstract: A method and a system in which selected wavelengths of a wavelength division multiplexed (WDM) signal are modulated with multicast data for multicasting data services on an optical network. The WDM signal is received from a hub node of the optical network, such as a unidirectional ring network or a bi-directional ring network. A four-port wavelength crossbar switch (4WCS) selectably switches selected wavelengths from the optical network to a modulator loop. The modulator loop includes a multicast modulator that modulates the selected plurality of wavelengths with the multicast data. Each modulated wavelength is then switched back to the optical network by the 4WCS switch, and sent to a plurality of subscriber nodes of the optical network. This architecture allows a facility provider to be physically separated from a content provider, and affords the flexibility of selectively delivering multicast content to individual subscribers.

Abstract: An optical conversion device for a shared FTTH distribution network including first and second optical fibers and an optical processing circuit. The optical processing circuit has an input for receiving a first optical analog signal carried by the first optical fiber and an output for providing a first optical digital signal for transmission via the second optical fiber. The optical processing circuit is configured to digitize the first optical analog signal and incorporate into the first optical digital signal. The optical analog signal may be an optical signal which is modulated by an RF signal, which is the same or similar to that of existing HFC networks. High loss electrical signals are converted to low-loss optical signals propagated within the optical plant. The combined optical analog and digital protocol supports analogous communications of existing HFC networks and the optical plant minimizes cost of fiber optic upgrade.

Abstract: Various methods and apparatuses are described for a wavelength division multiplexing passive optical network (WDM-PON) that performs bi-directional communication. The WDM-PON may include two or more remote distribution nodes in between a central office and the most distant optical network unit. Each remote distribution node is located in a physically separate location. A first remote distribution node has two or more optical network units connected to the first remote distribution node. Each remote node separates one or more wavelength channels from a composite optical signal distributed through that remote distribution node.

Abstract: A method for creating a full duplex fiber optic network using one single fiber optic cable of the multimode fiber type for simultaneous transmission and reception is described. The method includes the steps of equipping end user devices and switches with bidirectional transceivers utilizing multi-frequency lasers, allocation of wavelengths to the end user devices to assure interoperability of redundant systems, and connecting the elements with multimode fiber optic cable. The network components include multi-frequency bidirectional transceivers, switches, and multimode fiber optic cable. This full duplex fiber optic network can be created as a single-backbone network or multiple-backbone network operating in series or in parallel to provide backup redundancy. Various embodiments are disclosed to show the versatility and scalability of the network.

Abstract: A wavelength-division multiplexed self-healing passive optical network is capable of detecting cut-off and deterioration of feeder fiber and distribution fiber and restoring a network with a star structure. The network includes a central office, a remote node, and a plurality of subscriber units. Working and protection feeder fibers connect the central office to the remote node. A reflection unit at an end of the remote node connects to the central office for reflecting a monitoring optical signal transmitted from the central office. An output monitor stage at an end of the central office connects to the remote node for detecting the reflected monitoring optical signal and generating a control signal based on the presence of abnormality of the working and protection feeder fibers.

Abstract: A broadcast/communication convergence system, and an FTTH (Fiber To The Home) system that can accommodate broadcast signals of various channels and variable band signals by converging broadcast and communication signals and transmitting the converged broadcast and communication signals using an IEEE 1394 transmission method serving as a standard interface in the FTTH system for broadcast/communication convergence. An OLT (Optical Line Terminal) transfers a plurality of broadcast signals and a communication signal received from external broadcast and communication providers through a single optical signal (A).

Abstract: A wavelength division multiplexing based passive optical network is disclosed. The network includes an optical line terminal; a power optical splitter connecting to the optical line terminal by an optical fiber; and several optical network units. Each of the optical network units connects to the power optical splitter by each of other optical fibers by a random process.

Abstract: A wavelength selective optical switch of the present invention separates a WDM light emitted from an input port of an input and output optical system, according to wavelengths, by a diffraction grating, and thereafter, condenses the lights of respective wavelengths on MEMS mirrors respectively corresponding to the respective wavelengths, in a mirror array, to reflect them by a condenser optical system, to thereby switch optical paths for the respective lights. The condenser optical system is configured by combining a plurality of lenses whose focal distances are different from each other, and positions in an optical axis direction of the lenses are adjustable by a slide mechanism. Thus, despite an error in the focal distances of the condenser lenses, in a mounting angle of a spectral element or the like, a beam pitch at the condensing positions of the lights of respective wavelengths can be coincident with a mirror pitch in the mirror array.

Abstract: The present invention provides a PON system including a plurality of PONs (passive optical network), a plurality of house devices set in an end user's house, and a station side device including a plurality of PON interface sections connected to the house devices via the plurality of PONs, and a concentrating/distributing section for accommodating the plurality of PONs and concentrating and distributing signals via the plurality of PON interface sections; wherein the station side device has N (N is a positive integer) optical switch modules, each of which is connected to a PON interface section for current use among the plurality of PONs; and realizes 1:N redundant of the PONs by cascading the N optical switch modules.

Abstract: An optical module includes a transmitter optical sub-assembly comprising a transmitter configured to emit a multi-longitudinal-mode (MLM) spectrum signal having an emission spectrum comprising a plurality of distinct narrow-spectrum peaks each corresponding to a longitudinal mode in the transmitter. The emission spectrum can be shifted in wavelength by a change in the transmitter temperature. The optical module also includes a heating and cooling device configured to control the temperature of the transmitter in response to a temperature-control signal and a receiver optical sub-assembly configured to output a pair of differential digital signals in response to an input optical signal.

Abstract: In accordance with the teachings of the present invention, a method for distributing traffic in a distribution node in an optical network includes receiving wavelength division multiplexed (WDM) traffic in a plurality of wavelengths at at least one of a plurality of filters at the distribution node from at least one of the one or more upstream terminals. The optical network includes one or more upstream terminals, the distribution node, and a plurality of downstream terminals. Each of the filters is coupled to one or more of the upstream terminals by a plurality of separate fibers. The method further includes separating traffic in a first set of one or more wavelengths from traffic in a second set of one or more wavelengths at the filter. The method further includes routing the traffic in the first set of wavelengths for distribution to all downstream terminals.

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: An optical add/drop multiplexer (OADM) adapted to route optical signals having at least two different bit rates. The OADM has at least two sets of DWDM channels, e.g., with channels in a first set having a first bandwidth value suitable for the transmission of 10-Gb/s signals and channels in a second set having a second bandwidth value suitable for the transmission of 40-Gb/s signals. The first and second sets occupy two different spectral bands and the first set has two subsets of interleaved channels. In one embodiment, the OADM has first and second optical branches adapted to process optical signals corresponding to first and second groups of channels, respectively. The first group includes a first subset from the first set while the second group includes the second set and a second subset from the first set. Advantageously, OADMs of the invention may be used to create independent processing paths for different groups of channels. As a result, a communication system having those OADMs can be upgraded, e.g.

Abstract: An optical add and drop multiplexer system comprising a first module for providing a first signal; a second module for providing a second signal; and a modulator for receiving a channel of the first signal at a first location, the first location configured to actuate between a first configuration and a second configuration, wherein the modulator directs the channel of the first signal as an output signal when the first location is in the first configuration. The modulator may direct the channel of the first signal as a dropped signal when the first location is in the second configuration. The modulator may also receive a channel of the second signal from the second module at a second location configured to independently actuate between the first configuration and the second configuration.

Abstract: This invention provides a new architecture for a communication system between head-ends and end-users which expands bandwidth and reliability of the communication system. A mux-node receives communication signals from a head-end and forwards the received communication signals to one or more mini-fiber nodes. The connection to the head-end is via a small number of optical fibers and the connections to each of the mini-fiber nodes may be via one or more optical fibers that may provide full duplex communication. The head-end may communicate with the mux-node using digital or digital and analog signals. The mini-fiber nodes may combine the signals received from the head-end with loop-back signals used for local media access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and transmitted to the mux-node.

Abstract: A vehicle network system including one master device for receiving multimedia data and at least one slave device, which including the master device for generating optical signals assigned to multimedia services according to wavelengths, confirming the multimedia services to be provided to each of the at least one slave device, and transmitting optical signals of corresponding wavelengths to the at least one slave device; and the at least one slave device for receiving the optical signals, converting the received optical signals into electrical signals, and then reproducing a transport packet.

Abstract: An optical communication system is provided which includes an optical signal transmitter which communicates high bandwidth, high power frequencies. The optical signal transmitter includes a high efficiency/high power optical source such as an optical magnetron or a phased array source of electromagnetic radiation, and a modulator element. The modulator element may be within a resonance cavity of the high efficiency/high power optical source (intra cavity) or external to the cavity (extra cavity). The modulator element serves to modulate output radiation of the high efficiency/high power optical source to produce a modulated high frequency optical signal which may be transmitted through the air. The optical signal transmitter is particularly useful in providing the last mile connection between cable service operators and end users.

Abstract: Disclosed is a wavelength division multiplexing passive optical network (WDM PON) system in which an optical signal outputted from a central office is injected into a Fabry-Perot laser diode (F-P LD) as the light source of an optical network unit, so that the output wavelength of the optical network unit is injection-locked at the same wavelength as that of the optical signal outputted from the central office, thereby enabling the optical network unit to output an optical signal having the same wavelength as that of the optical signal outputted from the central office. In accordance with this system, it is possible to transmit and receive forward and backward data at the same wavelength by the unit of channels. Since inexpensive F-P LDs are used as respective light sources of the central office and optical network units, it is possible to efficiently and economically implement a WDM PON system.

Abstract: A WDM (Wavelength Division Multiplex) terminal device located in a WDM network includes a multiplexing unit that multiplexes a wavelength of a client signal having a single wavelength or a wavelength of at least one of a first plurality of client signals whose wavelengths are multiplexed, to wavelengths of a second plurality of client signals received with their wavelengths being multiplexed, and transmits the second plurality of client signals. Thus, the WDM terminal device can multiplex wavelengths of a plurality of client signals received from a metro WDM terminal device located at a distant place, to a wavelength of another client signal without separating the plurality of client signals by each wavelength, thereby achieving accommodation of a plurality of client signals whose wavelengths are multiplexed, at low cost.

Abstract: The invention relates to the distribution of a synchronization signal in an optical communication system which is inherently asynchronous. In order to accomplish a cost-efficient mechanism for transmitting a synchronization signal in such a system, the amplitude of a payload signal is modulated with the synchronization signal, whereby an amplitude-modulated payload signal is obtained. This amplitude-modulated payload signal is transmitted as an optical signal to the opposite end of an optical link, where the synchronization signal is separated from the payload signal.

Abstract: Processing a received optical signal in an optical communication network includes equalizing a received optical signal to provide an equalized signal, demodulating the equalized signal according to an m-ary modulation format to provide a demodulated signal, decoding the demodulated signal according to an inner code to provide an inner-decoded signal, and decoding the inner-decoded signal according to an outer code. Other aspects include other features such as equalizing an optical channel including storing channel characteristics for the optical channel associated with a client, loading the stored channel characteristics during a waiting period between bursts on the channel, and equalizing a received burst from the client using the loaded channel characteristics.