Abstract: Optical equalization across N (an integer, N>1) channels of a multi-channel link of a communications network, is accomplished by averaging effects of optical performance variations within each of the M (an integer, M>1) parallel data signals. At a transmitting end node of the link, each one of the M data signals are distributed across the N channels of the link. Thus a substantially equal portion of each data signal is conveyed through the link in each one of the N channels. At a receiving end node of the link, respective bit-streams received over the N channels to are processed recover the M data signals. As a result, bit error rates of the bit-streams received through each channel are averaged across the M data signals, all of which therefore have a substantially equal aggregate bit error rate.

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 time frame switching method and system of data units that utilize a global common time reference, which is divided into a plurality of contiguous periodic time frames. The system is designed to operate with high-speed wavelength division multiplexing (WDM) links, i.e., with multiple lambdas. The plurality of data units that are contained in each of the time frames are forwarded in a pipelined manner through the network switches, wherein at every stage of the pipeline is tuned to a new wavelength by using a wavelength converter. Furthermore, the incoming wavelength of a time frame and wavelength determines to which output port the data units in this time frame will be switched, while the new wavelength and time frame determine to which output the data units in this time frame will be switched in the next switch on the route. The outcome of this switching method is called wavelength conversion based fractional lambda switching.

Abstract: Architecture for efficient processing of the evolving OTN transmission technology, standardized under ITU-T G.709, in conjunction with existing and emerging SONET/SDH protocol signals, standardized under ANSI T1.105/ITU-T G.707. The new architecture allows processing the SONET/SDH signals, and/or OTN signals, and/or SONET/SDH mapped into OTN signals more efficiently. The architecture further allows processing and multiplexing of lower order signals into a higher order signal such as quad OC-192 into OC-768 or quad OC-192 into OPU3 and OTU3. This architecture uses an embedded processor to process some of the signals' overhead in software, contributing to an additional level of flexibility in the processing. This architecture enables customization and allowing for future standard updates and upgrades. The architecture can be upgraded to SONET OC-3072, SDH STM-1024 and OTU4, which currently are not standardized. The architecture can also be used for the implementation of SONET OC-192 with OTN OTU2.

Abstract: An optical packet switch switches optical packets according to bit-rates at which the optical packets are provided. For example, optical packets that are received at similar bit-rates may be routed to a destination at separate time slots over a single channel wavelength, and optical packets that are received at different bit-rates may be routed to the destination over separate channel wavelengths. When optical packets are provided at different bit-rates on a plurality of input paths, optical packets provided at low bit-rates may be compacted before switching to the destination. Alternatively or additionally, the bit-rates of the optical packets may be balanced before switching to the destination. Bandwidth contention among optical packets may be resolved by polarizing optical packets originating from separate input paths in different polarization directions, and merging optical packets having different polarization directions onto a single switched channel wavelength.

Abstract: An optical transmission system of the present invention includes input ports to which laser beams are respectively input, condensing, input optical elements, input reflectors corresponding one-to-one to the input optical elements each, output reflectors, output optical elements, and output ports. Assume that maximum one and minimum one of optical distances between the input optical elements and the output optical elements are DL and DS, respectively. Then, the beam waist position Q of the laser beam output from the input optical element closest to the input port satisfies a relation: 0.9(DL+DS)/4?Q?1.1(DL+DS)/4.

Abstract: A data transmission system employs a method of aligning transmission lanes with reception lanes in a multiplexing arrangement. A plurality of control symbols and lane identifiers are transmitted on each of the transmission lanes. The transmission lanes are divided into groups for time-division multiplexing. Within the groups, the transmission lanes are time-division multiplexed and then wave-division multiplexed onto a data link. Upon reception, wave-division and time-division demultiplexing is conducted to extract groups of reception lanes corresponding to the groups of transmission lanes. One of the reception lanes in each group of reception lanes is monitored for receipt of a control symbol followed by a lane identifier. Upon receipt, the lane assignment of the reception lanes is rotated within the particular group if the received lane identifier does not match the identity of the reception lane being monitored.

Abstract: Various methods and apparatuses are described for a multiple wavelength light source. The multiple wavelength light source may be located in a central office to supply a first broad band of wavelengths for a one or more passive optical networks. The multiple wavelength light source generates a series of four or more pulses of light in the first broad band of wavelengths. Each pulse of light in that series has a different center wavelength. The series of pulses of light in the first broad band of wavelengths may be repeated at a channel data rate of an optical receiver at a subscriber's location.

Abstract: Disclosed herein is a device including first and second optical couplers and a loop optical path. The first optical coupler includes first and second optical paths directionally coupled to each other. The loop optical path includes an optical fiber as a nonlinear optical medium, and connects the first and second optical paths. The second optical coupler includes a third optical path directionally coupled to the loop optical path. The optical fiber has an enough large nonlinear coefficient. The wording of “enough large” means that the nonlinear coefficient is large enough to reduce the length of the optical fiber to such an extent that the optical fiber has a polarization maintaining ability. By using such an optical fiber having an enough large nonlinear coefficient, a relatively short optical fiber can be used as the nonlinear optical medium.

Abstract: An optical interconnect comprises an input configured to receive light of a plurality of light wavelengths and a plurality of holographic optical elements. Each element configured to reflect one out of the plurality of light wavelengths and allowing others of the plurality of wavelengths to not be reflected. Each of a plurality of prisms is configured to rotate received light at a different angle than any of the other prisms. For each holographic optical element, one of the plurality of prisms is positioned to receive and rotate light reflected by that holographic element. Each of a plurality of beam splitters is positioned to receive light rotated by a respective one of the plurality of prisms and all the plurality of beam splitters direct light to an output of the optical interconnect.

Abstract: A technique for routing data within an optical network having a plurality of network nodes is disclosed. In one embodiment, the technique is realized by receiving data at a first network node via a first optical signal having a first wavelength. The first wavelength corresponds to a first optical frequency, and the first optical frequency is mapped to a first binary representation. The first binary representation is divided into a first plurality of fields, wherein at least one of the first plurality of fields corresponds to a routing label in a first label stack. A top routing label in the first label stack indicates a second network node. Based at least partially upon the top routing label, the data is transmitted from the first network node to the second network node via a second optical signal having a second wavelength. The first wavelength may be either the same as or different from the second wavelength.

Abstract: A method for providing high connectivity communications over a packet-switched optical ring network comprises a core optical ring having at least one node, the node being coupled to a subtending system by an optical crossbar switch, a source for generating a set of packets, a stacker for forming a first composite packet from the set of serial packets, the stacker coupled to the optical crossbar switch, and the stacker further coupled to the source for generating the set of packets, the first composite packet being parallel packets in a single photonic time slot, the first composite packet to be added to the core optical ring in a vacant photonic time slot via the optical crossbar switch, a second composite packet propagating on the core optical ring destined to be dropped at the node for further distribution on the subtending system via the optical crossbar switch, an unstacker for serializing the second composite packet dropped at the node, the unstacker coupled to the optical crossbar switch and a detector

Abstract: A system and method of selecting and viewing communication traffic transmitted over an optical channel selected from among a plurality of possible channels without disrupting the communication traffic occurring over the selected channel or other channels is presented. The system and method includes an optical channel analyzing switch which taps each of the possible plurality of channels and selects a specific channel for routing to a network analyzer. The signal on the selected channel, prior to being analyzed by the network analyzer, undergoes clock and data recovery and retiming/recombination to mitigate contamination from routing and switching the selected original signal between the signal source and the network analyzer. The retimed and recombined channel signal results in a signal, as presented to the network analyzer, which is representative of the original channel signal.

Abstract: A photonic switching device for switching without contention data in the form of optical packets includes a space switching matrix with a plurality of input ports and a plurality of output ports. A unit external to the space switching matrix includes a buffer memory common to all the output ports of the matrix. Each of the output ports provides access to the buffer memory via a space switching stage consisting of switches having a 1-to-2 switching function.

Abstract: A method and apparatus for reserving bandwidth in a network includes a series of elements. A demand matrix is calculated, for bandwidth requirements based upon communication needs among a plurality of nodes on the network. An integer number of time slots is provided, aligned around the network. Bandwidth is reserved for node-to-node communication based upon the demand matrix. The reserving of bandwidth reserves bandwidth between two nodes based upon time-slot alignment. Transmission is scheduled between the two nodes by reservation of wavelengths and time slots.

Abstract: A time frame switching method and system of data units that utilize a global common time reference, which is divided into a plurality of contiguous periodic time frames. The system is designed to operate with high-speed wavelength division multiplexing (WDM) links, i.e., with multiple lambdas. The plurality of data units that are contained in each of the time frames are forwarded in a pipelined manner through the network switches, wherein at every stage of the pipeline is tuned to a new wavelength by using a tunable laser. Furthermore, the incoming wavelength of a time frame determines to which output port the data units in this time frame will be switched, while the new wavelength determines to which output the data units in this time frame will be switched in the next switch on the route. The outcome of this switching method is called tunable laser based fractional lambda switching.

Abstract: An optical packet exchange apparatus and an optical switch in which search for a connection pattern between an input unit devoid of a packet to be transmitted and an output unit devoid of a packet to be received is reduced to enable fast switch control even in cases wherein the number of channels of the exchange apparatus is increased or network speed is higher. A plurality of input units, a plurality of output units and an optical switch are provided. Each input unit includes an input buffer unit, a parallel/serial conversion unit, an electrical/optical conversion unit, and a dummy packet insertion unit for sending a dummy packet if there is no packet to be transmitted. Each output unit includes an exchange counterpart contention resolution unit for controlling the exchange counterpart, an optical/electrical conversion unit, a serial/parallel conversion unit, and a packet eliminating unit. The exchange counterpart contention resolution unit controls the packet eliminating unit to eliminate a dummy packet.

Abstract: At the transmitter end, route information is converted to allocated frequency mixes that are used to produce route signals by modulating a carrier signal. The route signals produced are placed in front of and/or after at least one data packet and are transmitted within an optical data packet stream. At the receiver end, the route information is evaluated in terms of the frequency mix used for the modulation and the data packets are switched using the route information obtained from the frequency mixes.

Abstract: An optical data stream is converted to electrical signals which are applied to a time-slot interchanger. The time-slot interchanger recorders the packets or cells of the data stream to correspond to the schedule of an optical switch. The time-slot interchanger may contain a plurality of FIFOs implemented as circular buffers in a single dual port memory. The switch schedule may be determined by the average load between inputs and outputs and may be determined by the number of packets or cells queued from each input or each output in the time-slot interchangers.

Abstract: An ultra-low latency optical router with a peta-bit-per-second total aggregate switching bandwidth, that will scale to a total connectivity of 1000 by 1000, and beyond by modular upgrades, that utilizes advanced optical technologies to achieve such high capacity with two to three orders of magnitude less volume and power requirements than the electrical router counter part, that serves as a universal engine to other optical routers being developed by vendors and researchers today, that can function in the context of circuit-switching, flow-switching, burst-switching, and packet-switching, that uses advanced wavelength conversion technology to effectively achieve three methods of contention resolution in the router: deflection in wavelength, deflection in space, and buffering in time, and that interfaces a local network to the Supernet.

Abstract: A system and method for increasing bandwidth efficiency and data transmission performance of radio frequency wireless, optical wireless and fiber-optic digital communication links without requiring an increase in signal power. The system utilizes bandwidth efficient space-time coding to correct transmission errors and bandwidth efficient space-time modulation to dramatically increase data throughput without requiring additional signal bandwidth or power. Radio frequency wireless, optical wireless WDM and fiber-optic applications are achieved by utilizing space-time encoders, radio frequency sources, bandwidth efficient space-time modulators and power amplifiers combined with transmission devices such as one or more antennas, multifeed antennas, multimode antennas or for transmission by a suitable cable. At the receiver, the method is reversed.

Abstract: A system and method for increasing channel capacity in fiber-optical communication networks utilizing space and time modulation. The system utilizes a three-dimensional spatial field of time division multiplexing, polarization modulation, and wavelength division multiplexing to increase channel capacity. A plurality of transmitter data processors receive a plurality of channel inputs for transmission over the optical network. The transmitter data processor produces time division multiplexing of a plurality of data channel inputs into a plurality of temporal and spatial data streams. A plurality of optical sources receive and directly modulated by the plurality of temporal data streams which are then polarization modulated before being delivered to a wavelength division multiplexer for transmission over an fiber-optics cable.

Abstract: A multi-grained network includes edge modules that switch high-variance multi-rate data traffic, and independent core modules that switch paths having different granularities. The core may include core modules that switch fixed-size data blocks, core modules that switch channels or bands of channels, core modules that switch entire links, and core modules that cross-connect channels or links. To simplify the control functions, the core modules operate independently from each other. Direct link, band or channel connections may be established for selected ingress-egress edge module pairs, if traffic volumes warrant. The use of graded granularity in the core simplifies the control function and reduces network cost.

Abstract: The present invention is directed toward a distributed intelligence fiber-optic communication network in which node control processors (NCPs) associated with each network element periodically transmit identification and status information to the other NCPs in the network. Various faults in the network can thus be readily identified, and appropriate tasks for modifying the network in response to the fault (such as rerouting around a defective network element) can be carried out. Further, information continues to be distributed among the NCPs even if a break occurs in a segment of fiber in the network.

Abstract: A system and method for multiplexing an in-service optical time domain reflectometry (ISOTDR) session using the same wavelength as the data traffic for point-to-point or point-to-multipoint optical fiber networks while not impacting data transmission is disclosed.

Abstract: The present invention relates to an optical switching device for WDM systems based on multi-frequency lasers and optical couplers. A router/switch mapping of IP (or other protocols) subnets or addresses to an optical channel instead of a physical interface. Another embodiment of the invention implements the mapping directly at the source where the data transmission originates. The invention allows integration of WDM in the routers and switches, and ultimately in the information source. As a result, unnecessary opto-electrical conversion steps and physical interfaces are eliminated.

Abstract: A preferred WDM all optical packet switched router architecture and an integrated analysis method for determining said architecture are disclosed. The method of the present invention includes the steps of simulating, with a network simulator, the operation of a desired network topology having at least one baseline router, establishing a steady state in the network simulation, applying a router and network dimensioning algorithm to the desired network topology for a predetermined number of clock cycles, and determining the preferred network router architecture based on the predetermined number of clock cycles. The baseline router used in the method of this invention can be a WDM all optical packet switched router, and the preferred network router architecture can be a WDM all-optical packet switched router architecture.

Abstract: An intelligent photonic burst switching (PBS) module for use in a WDM optical switching network includes optical multiplexers and de-multiplexers, an optical receiver array, an optical transmitter array, a PBS fabric, and a control interface unit. The PBS module includes optical buffering in a form of tunable wavelength converters (TWCs) and variable time-delay optical circuits. The PBS module routes the received optical burst labels and network management control labels to the controller and optical burst data in a plurality of input lines, respectively. The optical output lines provide propagation paths for a plurality of TDM channels. More specifically, the controller processes the control signal and, responsive thereto, causes the PBS to route at least a portion of the data signal to one of the TDM channels. When the desired TDM channel is not available, the controller causes a TWC to effectively change the wavelength of at least a portion of the data signal.

Abstract: A multiplexer for producing an output continuous-wave train of electromagnetic radiation pulses from an input continuous-wave train of electromagnetic radiation pulses is disclosed, the pulse repetition frequency of the output train of pulses exceeding the pulse repetition frequency of the input train of pulses. The time domain multiplexer comprises a planar lightwave integrated circuit (PLC) at least two integrated beam couplers and at least two intermediate integrated waveguide paths arranged between said beam couplers, the optical lengths of said two waveguide paths being different. The optical beam path difference is chosen and said time beam couplers are designed in a manner that said device is for multiplexing trains of electromagnetic pulses with an input pulse repetition frequency exceeding 1 GHz into at least one train of electromagnetic pulses with an output pulse repetition frequency being larger by a factor N≧2.

Abstract: This invention provides a method and apparatus for spectral power monitoring by use of a polarization diversity scheme. In the present invention, a multi-wavelength optical signal is first decomposed into first and second polarization components, and the second polarization component is subsequently rotated by 90-degrees, prior to impinging onto a diffraction grating that provides a higher diffraction efficiency for the first polarization component. The diffraction grating separates the first and second polarization components by wavelength respectively into first and second sets of optical beams, impinging onto an array of optical power sensors. The inventive optical spectral power monitoring apparatus thus is able to minimize the insertion loss, while providing enhanced spectral resolution.

Abstract: A device and method for detecting rotational drift of mirror elements in a MEMS tilt mirror array used in an optical crossconnect. The optical crossconnect directs optical signals from an input fiber to an output fiber along an optical path by rotatably positioning mirror elements in desired positions. A monitoring device disposed outside of the optical path is used to obtain images of the MEMS array or to transmit and receive a test signal through the crossconnect for detecting the presence of mirror element drift.

Abstract: A passive optical network employing wavelength dependent routing uses two-phase signalling between a network controller and terminals. In a first phase, terminals are informed of the wavelength channel allocated to them for a second signalling phase, groups of terminals being allocated to each channel. In the second signalling phase, control signals indicate to the terminal the wavelength and time slots allocated to the terminal in the following data transmission phase.

Abstract: A connectionless packet network and an optical WDM network are interconnected by one or more optical interface modules (gateways) that include both optical to electrical interfaces, as well as a connection management module, or control element, that is arranged to control the OADM's and the configuration of lasers and port assignments within the gateways, such that a route through the optical network to a desired endpoint is selected. The OADM's can be programmed, (i.e., locally or remotely controlled by the control element) such that the wavelengths that can be added or dropped by an OADM can be changed, thereby allowing routes to be established through the optical network, from an originating gateway to a destination gateway. In addition, the optical interface modules can include a plurality tunable lasers that can be controlled such that routes can be established through the optical network without requiring changes to the routing table that associates particular endpoints with particular ports.

Abstract: One embodiment of the present invention provides a system that facilitates optical switching. The system starts by receiving a plurality of optical input signals. The system then divides each of the plurality of optical input signals into a plurality of wavebands that can be carried on a single optical fiber, wherein each waveband includes a predetermined subset of the wavelengths in the optical signal. Once the optical input signals have been divided into wavebands, the wavebands are then routed through a waveband switch. After being routed through the waveband switch, the wavebands are combined to form a plurality of optical output signals, where each optical output signal can possible include wavebands from different optical input signals. Additionally, some of the wavebands can be divided into wavelengths, and the wavelengths can be routed through a wavelength switch or a traffic grooming switch.

Abstract: An optical switching apparatus in an optical communication network selectively combines and separates series of optical signal samples using OTDM and/or WDM. In upstream communication, the optical switching apparatus optically converts n series of upstream optical signal samples having the upstream optical signal samples carried over channel wavelengths &lgr;1, . . . ,&lgr;n at data rates DR1, . . . ,DRn respectively into a combined series of upstream optical signal samples having the upstream optical signal samples carried over a channel wavelength &lgr;D at a combined data rate DRc which is greater than any one of the data rates DR1, . . . ,DRn. The combined series of upstream optical signal samples is then routed to a destination route.

Abstract: Method for forming the virtual topology (21-45) of an ATM-layer where the ATM-layer is carried over an optical network (1) where inputs such as the physical topology (2-8, 11-16) and constraints of physical nature are given, thereafter forming node-pairs with end-to-end connections according to some known optimal routing algorithm, and finally applying a non-deterministic mathematical approach to obtain an optimal virtual topology with the objective of minimising the need for necessary electrical processing (50, 60, 70, 80) in the nodes (11-16) of the network (1).

Abstract: Disclosed herein is an optical cross-connect device including first wavelength demultiplexing sections each for demultiplexing WDM (wavelength division multiplexed) signal light into a plurality of optical signals, wavelength group generating sections each for receiving the optical signals from each first wavelength demultiplexing section to generate wavelength groups, first wavelength multiplexing sections each for receiving each wavelength group from each wavelength group generating section to output a WDM wavelength group, a routing section for routing the input WDM wavelength groups, second wavelength demultiplexing sections each for receiving each WDM wavelength group from the routing section to output a wavelength group having a plurality of wavelengths, wavelength converting sections each for performing wavelength conversion of each optical signal of the wavelength group output from each second wavelength demultiplexing section, and second wavelength multiplexing sections each for wavelength division m

Abstract: In a signal demultiplexing device formed by a probe light source, a wavelength converter, and a wavelength demultiplexer, the probe light source is formed by a plurality of sub-probe light sources configured to respectively generate the sub-probe lights with the prescribed different wavelengths for respective time-slots, a multiplexer configured to multiplex the sub-probe lights generated by the plurality of sub-probe light sources, and a phase different giving unit configured to give phase differences corresponding to time-slot positions to the sub-probe lights multiplexed by the multiplexer, and to sequentially output the sub-probe lights with the phase differences in correspondence to respective time-slots.

Abstract: An optical shell node is provided with an ability to perform time switching on signals received from subtending edge nodes and channel switching on signals received from other shell nodes and destined for the subtending edge nodes. The signals received from the subtending edge nodes may be aggregated into signals that are channel switched by optical core nodes or by other shell nodes toward destination edge nodes. A resultant network formed of these shell nodes along with channel-switching core nodes and subtending-upon-shell-node edge nodes is capable of expansion beyond a continental scale, can support large numbers of edge nodes and has a higher bit rate capacity than known optical network structures.

Abstract: A method and apparatus for control and data burst routing in WDM photonic burst-switched network is disclosed. In one embodiment, only the control bursts and network management labels are going through optical-electrical-optical conversion inside the photonic burst switching (PBS) module. The building blocks of the control processing unit inside the PBS module may include input and output buffers, control burst parser, burst scheduler, PBS configuration and control, contention resolution, forwarding engine, network management controller, control burst generator, and queue manager. The contention resolution block may be used to resolve resource contention between multiple data bursts. Such contention resolution may take the form of adding additional delays to one of the data bursts, changing one of the data bursts to an alternate wavelength, or dropping some of the data bursts based on various criteria such as relative priority and wavelength.

Abstract: An electro-optic interface structure for use in a multi-protocol OEO WDM network, the interface structure comprising a rate multiplying encoding unit for applying a rate multiplying line code to an electrical transmit data signal prior to conversion of the electrical transmit data signal into an optical WDM channel signal, and a rate dividing decoding unit for applying a corresponding rate dividing line code to an electrical receive data signal converted from a received optical WDM channel signal, wherein the encoding unit is arranged such that, in use, the same rate multiplying line code can be applied to electrical transmit data signals of different protocols, and wherein the decoding unit is arranged such that, in use, the application of the same corresponding rate dividing line code can create electrical signals of different protocols.

Abstract: A modular optical switch includes a set of optical switch modules connected in a mesh, a master controller for the whole optical node and a switch-module controller for each of the optical switch modules. The optical switch modules receive optical signals from, and transmit optical signals to, edge nodes based on connection requests received from the edge nodes. The master controller acts to select a path, using a simple or compound time-slot matching process, through the mesh of switch modules for each optical signal related to a connection request. Advantageously, the optical switch modules are fast switching, enabling the use of time-sharing schemes such as TDM, and the modular optical core node is made practical by efficient path selection at the master controller. A hybrid modular switch may include both optical and electronic switch modules, a master controller, and a switch-module controller for each of the switch modules.

Abstract: A method of reading and updating a packet header of an optical packet for transmission over an optical network involves dividing the input signal into two paths. The signal in one path (46) is converted into an electrical signal and the header information is read. The data stored in the packet header is removed optically in the other path (44) by constraining the packet header signal to have a constant amplitude. Updated header information is used to modify the constant amplitude signal using a modulator (60). An apparatus is provided for implementing the method. The header is thus read in the electrical domain, but it is updated optically.

Abstract: A method and apparatus for multiplexing/de-multiplexing optical signals is disclosed. The method and apparatus are applicable to a range of optical multiplexing techniques including, but not limited to: wavelength division multiplexing (WDM), dense wavelength division multiplexing (DWDM) and frequency division multiple accessing (FDMA). The disclosed devices do not require active components. The disclosed devices may be implemented with fiber or fiberless optical communication systems including telecommunications systems. The devices may be used on their own or as part of a larger system such as a multi-stage mux/demux, an optical switch, or router. Additionally, the devices are passively thermally stabilized with the result that their tuning is substantially invariant across a wide temperature range. The optical device includes a linear polarizer, at least one wave plate and a beam displacer/combiner.

Abstract: An intelligent optical burst switching module for use in an optical switching network includes an optical receiver array, optical transmitter array, a core switch unit and a control unit. The core switch unit routes optical control and data signals received via a plurality of optical input lines to the optical receiver array and a plurality of output lines, respectively. The optical output lines provide propagation paths for a plurality of TDM channels. The optical receiver array converts the optical control signal to an electrical signal. The control unit processes the converted control signal and, responsive thereto, causes the core switch unit to route at least a portion of the data signal to one of the TDM channels. The control unit also causes the optical transmitter to generate a new optical control signal and cause the switch unit to route the new control signal to another of the TDM channels.

Abstract: A telecommunications network having a ring topology overlaid with an Ethernet. An add/drop multiplexer (ADM) employing wave division multiplexing (WDM) hardware is implemented at each node of a multi-node fiber-based network. The ADM contains a robust protection scheme for reliability. The WDM allows the data traffic of the incumbent network, for example, a SONET network, to be carried over one or more frequencies while the data traffic of one or more packet-based networks may be carried over one or more other frequencies. Each ADM has protection switches, for example, micro-electromechanical switches. The protection switches provide a no-load bypass capability. A failed node can be shunted from the ring, allowing the Ethernet data to bypass the node uninterrupted. The switches also provide a self-test capability. The ADM interfaces can be checked by coupling the receiving path and the transmission path. This allows the ADM transceivers to communicate with each other.

Abstract: An optical transmission system capable of alleviating the non-linear optical effect from overhead portions of a bit pattern comprised of a plurality of bits, wherein a plurality of optical transmit devices input a clock signal of identical phase and frequency, and optical signals whose overhead positions are changed on each wavelength by respective variable delay lines under the control of a phase controller are sent to a transmit side WDM device. At the transmit side WDM device, these optical signals are multiplexed in a wavelength multiplexer and sent to the receive side WDM device. Receive side optical transmission devices receive the respectively isolated optical signals. A phase controller offsets the positions of the optical signals and sends them to the overhead on each wavelength so that the non-linear effect of the receive optical signal is suppressed and a satisfactory signal can be received.

Abstract: A system and method are disclosed for carrying additional information data on multiplexed signals which are modulated on different wavelengths. An information code such as an address or control data for a particular data signal at a selected wavelength is overlaid on the parallel multiplexed signals. The information code may be overlaid by attenuation or changing the amplitude of the different signals. A separate marker channel at a separate wavelength is also multiplexed with the data signals to indicate the presence of an information code. An optical data detector array is used to optically determine the encoded address by comparing the signals with light levels and producing an output when a matching code is detected. The optical data detector array uses a series of detectors each corresponding to the wavelength of light signals carrying the information data.

Abstract: A method and system for using burst mode transmission on multiple optical wavelengths is disclosed. In a passive optical network, a synchronization signal is transmitted from a central terminal to remote terminals and burst data signals are transmitted from remote terminals to the central terminal. A first group of remote terminals transmits burst data signals in respective timeslots that are synchronized to the received synchronization signal and multiplexed at a first optical wavelength. A second group of remote terminals transmits burst data signals in respective timeslots that are synchronized to the received synchronization signal and multiplexed at a second optical wavelength. The timeslots are synchronized and phase aligned with each other such that optical crosstalk interference between adjacent optical wavelengths is avoided and each wavelength can be spectrally spaced as close as possible to adjacent wavelengths.

Abstract: The biggest bottleneck in the Internet today is caused by the slow speed of routers, compared to the speeds that are achieved by optic fibers with DWDM (Dense Wave Division Multiplexing). Packet switching or something similar to it is needed not just for better utilization of the lines, but also because it is superior to circuit switching in many ways, such as better scalability as the Internet grows, better handling of traffic congestions, and better routing flexibility. But optical routers are currently unable to do packet switching except by translating the data to electronic data and then back, which is very inefficient.