Abstract: An optical switch for switching data in a network. The switch includes a housing. The switch includes a transmitter receiver means which transmits to or receives from the network the data. The transmitter receiver means is disposed in the housing. The first optical path forms a first closed optical loop along which the data flows in a first direction. The switch includes a second optical path forming a second closed optical loop along which the data flows in a second direction. The second direction is opposite the first direction. The first and second optical paths each having a portion in which the transmitter receiver means is inserted into or removed from the first and second optical paths without disruption of switching of data by the switch. A method for switching data in a network.

Abstract: It is an object of the invention to provide a network topology for OCDM signals. Coding splitters combining both coding and splitting functions are provided. The coding splitters themselves can be made from cascaded Mach Zehnder filters which are located somewhere in the network and which can be integrated using planar waveguide technologies. Each OCDM transceiver as well as the network is connected to the splitter via a pair of fibers for the two transmission directions. This set-up has the advantage that the same splitter can be used for both directions to and from the transceivers on one side and to and from the network on the other side.

Abstract: A light regulating device and photonic crystal display device utilizing bandgap controls including a photonic crystal including a material that is capable of varying its refractive index in accordance with an electric field, the photonic crystal having a photonic bandgap in a specific frequency range; and an upper transparent electrode and a lower transparent electrode arranged on an upper side and a lower side of the photonic crystal, respectively, to which a voltage is applied, wherein a size of the photonic bandgap of the photonic crystal is controlled by the voltage applied between the upper transparent electrode and the lower transparent electrode. With the present invention, a reflection-type or penetration-type display is available which has a simple pixel structure, a high light efficiency, and a high color contrast ratio, the display using high reflection factors depending on color ranges of a photonic crystal.

Abstract: A method and system for channel-by-channel dispersion compensation mitigate inter-channel interference. Inter-channel cross-talk is reduced by introducing a walk-off between the transmission channels after each amplified transmission span. A compensator assemblage comprises a first compensator that is an ODC dispersion compensator and a second compensator that is a channel-by-channel dispersion compensator. While the dispersion introduced into each channel by the first compensator is annihilated by the second compensator, the walk-off between the channels, introduced by the first compensator remains. As a result, the effects of non-linear inter-channel interference are mitigated.

Abstract: Circuitry for a node of an optical communication network is configured to mux (i.e., combine) one or more incoming customer signals for transmission as a single outgoing optical signal and to demux (i.e., split) an incoming optical signal into one or more outgoing customer signals, where the muxing and demuxing clocks are selected from one or more customer clocks recovered from the one or more customer signals, an input clock recovered from the incoming optical signal, and a local clock generated by a local clock generator. When configured for an add/drop configuration, the circuitry selects (1) the muxing clock from the one or more customer clocks, the input clock, and the local clock and (2) the demuxing clock from the input clock and the local clock. When configured for a drop/continue configuration, the circuitry is configured to select both the muxing and demuxing clocks from either the first input clock or the local clock.

Abstract: When sampled simultaneously by a set of synchronized high intensity beams, a device consisting of a sequence of interlinked Nonlinear Sampling-Gates, through which a signal beam propagates, generates a replica of the intensity of the signal beam, during the interaction period. The device may be implemented optically or electrically as an ultra-high speed parallel receiver and when sampled by a femtolaser may be used to read a data train in parallel and thus at almost in real time. The device may also be used to stretch, compress, multiplex, demultiplex, read headers and help switch data trains optically in communication networks.

Abstract: A bi-stable micro-actuator is formed from a first and a second silicon-on-insulator wafer fused together at an electrical contact layer. A cover with a V-groove defines an optical axis. A collimated optical signal source in the V-groove couples an optical signal to an optical port in the V-groove. A mirror surface on a transfer member blocks or reflects the optical signal. The transfer member has a point of support at the first and second end. The mirror blocks or reflects the optical axis. An expandable structure applies a compressive force between the first and second point of support of the transfer member along a compressive axis to hold the transfer member in a bowed first state or a bowed second state. A control signal applied to a heating element in the expandable structure reduces the compressive force, switching the transfer member to a second state.

Abstract: The optical hybrid device includes input optical fiber(s), output optical fiber(s), a lens, a broadband or passband filter, a movable mirror, and an actuator operative to move the mirror or the filter. Depending on a voltage applied to the actuator, the actuator selectively sets the mirror or filter to each of a plurality of positions, so that selected portion(s) of radiation from one or more input beams carried by the input optical fiber(s) are conveyed to the output optical fiber(s); whereby the device performs two or more of the functions of wavelength division multiplexing or demultiplexing, attenuation, switching, filtering and tapping functions.

Abstract: An optical router integrated in an InP-based substrate bonded to a single thermo-electric cooler for packet-based networks utilizing wavelength-division multiplexing (WDM) on silica fibers. Input and output arrayed waveguide gratings (AWGs) respectively demultiplex and multiplex the WDM signals to and from multiple transmission fibers. Input and output wavelength converters are connected between the input and outputs AWGs and a switching AWG. The output converts may include a tunable laser and interferometer formed in the same substrate. The header information is preferably carried out-of-channel from the WDM data signals, either in the same fiber band or a different one. Photodetectors and laser diodes are formed in the same substrate.

Abstract: A system and method of providing multiple simultaneous services to several destinations is disclosed. The system includes a central office providing multiple digital services to several destinations. In addition, the system includes a curbside hub directing signals sent from the central office to the destinations. Each destination also includes a home-side interface unit for receiving and sending signals between the destination and the curbside hub. The curbside hub is located within the vicinity of the destinations. The curbside hub is connected to the central office by a first fiber optic link. Additionally, the curbside hub is connected to each home-side interface unit by a home-side fiber optic link. The curbside hub electrically multiplexes and demultiplexes signals between each home-side interface unit and the curbside hub. The curbside hub also optically multiplexes and demultiplexes signals transferred between the central office and the curbside hub.

Abstract: An multiplex transmission apparatus that realizes a receiving system using a phased array antenna with high efficiency and low cost is provided. A delay controller 102 gives a time delay to a local oscillation signal outputted from a signal source 101. First and second optical transmitters 1031 and 1032 each converts the local oscillation signal and the delayed local oscillation signal into optical signals. A first optical multiplexer 104 multiplexes the optical signals for transmission. An optical separator 106 separates the multiplexed optical signal. A first multiplexer 1071 multiplexes first and second main element signals, while a second multiplexer 1072 multiplexes first and second sub-element signals. First and second optical modulators 1081 and 1082 each modulates the optical signal with multiplexed electrical signal group. A second optical multiplexer 109 multiplexes the modulated optical signals for transmission.

Abstract: A method for dynamically allocating bandwidth among ATM cells and packets scheduled for output from an aggregation multiplexer of a transport-layer device configured to multiplex both ATM cells and packets onto the same channel of an optical fiber. The method includes local control and relative priority lookup of incoming ATM cells and packets to support output decision. When compared to currently employed methods, the required level of coordination with the receiving circuit for dynamic bandwidth allocation is substantially lower, thereby reducing operational complexity for network operators and latency for critical data when reallocating bandwidth.

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: A detunable Fabry-Perot interferometer, and method of tuning a Fabry-Perot interferometer are provided. The Fabry-Perot interferometer includes a first mirror, a second mirror oriented with respect to the first mirror so as to define a Fabry-Perot cavity therebetween, and an actuator configured to adjust a resonant wavelength of the Fabry-Perot cavity by varying a gap between the first and second mirrors, wherein the actuator is configured to selectively maintain the first and second mirrors in a substantially non-parallel relationship while the resonant wavelength of the Fabry-Perot interferometer is varied. The detunable Fabry-Perot interferometer can be employed in a multiplexer of a telecommunications system, as provided.

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: The present invention provides an optical demultiplexer and an optical multiplexer the transmission characteristics of which are unlikely to be affected by fabrication errors and which have small group delay dispersion. A cross output port (X-OUT) of a second optical demultiplexer element (DEMUX) is selected, and a through output port (T-OUT) of a third DEMUX is selected. A T-OUT of a first DEMUX has a passband equal to the X-OUT of the second DEMUX, and a X-OUT of the first DEMUX has a passband equal to the T-OUT of the third DEMUX. The T-OUT of the first DEMUX has group delay characteristics opposite to those of the X-OUT of the second DEMUX, and the X-OUT of the first DEMUX has group delay characteristics opposite to those of the T-OUT of the third DEMUX.

Abstract: A so-called digital “wrapper” is employed in conjunction with an optical channel client signal payload envelope to carry optical channel associated optical channel overhead. That is, the digital wrapper transports optical channel associated optical channel overhead and other monitoring information. This is realized by adding additional capacity, i.e., bandwidth, to the client signal payload envelope. The additional capacity is added “around” the payload envelope and the client signal floats in the payload envelope. This is effected in such a manner that the digital wrapper is independent of the type of client signal that is being transported on the optical channel. Indeed, as such the optical payload envelope is essentially a client optical signal independent, constant bit-rate channel. Moreover, in addition to the digital wrapper providing capacity for the optical channel overhead, it can also be employed to provide a forward error correction capability.

Abstract: The present invention provides an improved switchable interleaved channel separator device. The switchable interleaved channel separator device utilizes an adjustable reflective non-linear interferometer, which performs both switching and wavelength polarization sorting functions, so that overall complexity of the device is reduced. Further, because the adjustable non-linear interferometer is a reflection element, signal light paths are folded back upon one another so as to realize an overall reduction in the device's size, as well as the capability of performing optical couplings predominantly or wholly at a single side or at adjacent sides of the device.

Abstract: A wavelength division multiplexed optical communication system includes a plurality of optical line terminals which may be part of separate in service networks, each having a line interface and an all-optical pass-through interface including a plurality of pass-through optical ports, and each also including a plurality of local optical ports which are connectable to client equipment and an optical multiplexer/demultiplexer for multiplexing/demultiplexing optical wavelengths. The optical multiplexer/demultiplexer may include one or more stages for inputting/outputting individual wavelengths or bands of a predetermined number of wavelengths, or a combination of bands and individual wavelengths.

Abstract: Disclosed herein is a multiplex laser light source equipped with a plurality of semiconductor lasers, a single multi-mode optical fiber, and a light-collecting optics system for collecting laser beams emitted from the plurality of semiconductor lasers and then coupling the collected laser beams to the multi-mode optical fiber.

Abstract: An optical switching apparatus includes an optical switch having a plurality of input ports and output ports, optical amplifiers, monitor circuits, optical amplifiers monitor circuits, and a controller that controls the optical switch. The optical amplifiers are connected to the input ports of the optical switch. The monitor circuits are connected to the output ports of the optical switch. The controller selects one of the plurality of the monitor circuits based on predetermined rules to obtains the loss at the output ports and/or the differential loss between the channels of the optical switch. The controller further selects one of the optical amplifiers based on the configuration of the optical switch to compensate the loss and the differential loss among the different channels of the optical switch by pre-amplifying the optical signals before they reach the input ports of the optical switch.

Abstract: Wavelength division multiplexing signal light is fed into an arrayed diffraction grating type optical demultiplexer, demultiplexed signal light components are outputted from a plurality of output ports, whether there is a signal light component or not is detected by each photodiode of a photodiode array, and a counter unit calculates the number of signals from the result of detection. Here, the output wavelength interval of &Dgr;&lgr;o of the output ports is set to &Dgr;&lgr;o=&Dgr;&lgr;i/m (where m is an integer of at least two) with respect to the signal wavelength interval &Dgr;&lgr;i of the wavelength division multiplexing signal light, whereas the photodiode array is sectioned into m photodiode array groups in which the output signal wavelength interval is &Dgr;&lgr;i.

Abstract: Optical frequency-division filters for multiplexing and demultiplexing operations by combining wavelength-selective filtering and polarization properties of optical signals.

Abstract: The present invention provides an optical packet switch (3, 4) that facilitates efficient provisioning of packet services through a predominantly circuit-switched optical transport network infrastructure (1). In particular, the optical packet switch (3, 4) fits within a network where circuit and packet-switched traffic are transported together through the optical transport network (1). Fast switching is provided for packet traffic where granularity below the wavelength level is required, while slow wavelength switching and routing is facilitated at the same time. Fast switching and packet traffic aggregation for efficient bandwidth utilisation is performed at the edge where the optical transport network (1) interfaces with the IP domain (6), where dynamic and fast wavelength allocation for packet traffic is required.

Abstract: An optical multi/demultiplexer having a desirable multiplexing-and-demultiplexing performance throughout the entire wavelength band for signal transmission, and an optical multiplexer whose multiplexing performance is less susceptible to the shift of the center wavelength and to the fluctuation of the center wavelength due to temperature change and whose optical circuit can be miniaturized. The optical multi/demultiplexer comprises a substrate and an optical circuit formed on the substrate. The optical circuit comprises a circuit having a wavelength dependency, which may be a Mach-Zehnder interferometer (MZI), and a Y-junction. In one aspect of the optical circuit, the Y-junction is connected to one end of each of the two optical waveguides included in an MZI. In another aspect of the optical circuit, the Y-junction is connected to one end of an optical waveguide included in an MZI and to one end of another optical waveguide, whether it is independent or belongs to another MZI.

Abstract: A light source generates a continuous wave light. A data signal source generates a data signal. A pilot signal is multiplexed on the data signal. The frequency of the pilot signal is much lower than that of the data signal. An LN modulator modulates the continuous wave light using the data signal on which the pilot signal is multiplexed. A data detection unit monitors whether a frequency component two times as high as the frequency of the pilot signal is contained in the output light from the LN modulator. Unless the frequency component two times as high as the frequency of the pilot signal is contained, it is determined that the data signal has stopped or disappeared, and outputs an alarm.

Abstract: A method for integrating power monitoring capabilities with passive demultiplexing operations, utilizing the high-order diffraction from an optical diffraction grating. The technique helps avoid insertion loss and polarization dependent loss penalties, and device size penalties, typically incurred with optical taps and multiple diffraction gratings. The technique can also be modified slightly to provide information on channel wavelength and optical signal-to-noise-ratio, as well as channel power.

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 optical method and system are presented utilizing a 2×2 broadcast switch device for performing various logical operations, such as neural network, logical gates, as well as performing analog to-digital conversion, and interferometric testing. The switch device is of the kind performing polarization coding of light passing therethrough.

Abstract: An arrayed waveguide grating optical multiplexer/demultiplexer is provided to suppress a temperature depending characteristic of a center wavelength. The arrayed waveguide grating comprises at least one optical input waveguide, a first slab waveguide, an arrayed waveguide, a second slab waveguide, and a plurality of optical output waveguides. The first slab waveguide is separated on an cross separating plane which is intersected to a path of light passing through the first slab waveguide to constitute separated slab waveguides. A slide moving member is provided which may move at least one of these separated slab waveguides along the cross separating plane, depending upon the temperature. A front surface side of the waveguide forming region and a rear surface side of the substrate are sandwiched by a positional shift suppressing member such as a clip. The possition depressing the waveguide forming region by the clip is escaped from the optical axis of the separated slab waveguides.

Abstract: A method of controlling a network (115) through which information is transmitted in channels (&lgr;1 , &lgr;2 , . . . &lgr;n) among nodes includes: (a) providing at a node a device (108) for removing from the network (115) and replacing on the network (115) a selected one (&lgr;i) of the channels, the device (108) including a first input port from the network (115) to the node and a first output port from the node to the network (115); (b) taking a measure of the strength (P&lgr;iDROP) of the received channel (&lgr;iDROP); (c) regenerating the channel (&lgr;iIN); (d) adjusting (114) the strength (P&lgr;iADD) of the regenerated channel (&lgr;iIN) to approximate the strengths of the remaining channels ((&lgr;1, &lgr;2, . . . &lgr;n)-&lgr;i; and (e) combining the regenerated and strength-adjusted channel (&lgr;iADD) with the remaining channels ((&lgr;1, &lgr;2, . . . &lgr;n)-&lgr;i) at the output port.

Abstract: A silicon demultiplexer, a plurality of silicon switches and a silicon multiplexer are monolithically integrated on a single silicon chip. In embodiments, the silicon demultiplexer and the silicon multiplexer each comprise a diffraction grating. In other embodiments, the silicon demultiplexer and the silicon multiplexer each comprise an arrayed waveguide grating. In various exemplary embodiments, the silicon optical switches comprise optical switches, micromachined torsion mirrors, electrostatic micromirrors, and/or tilting micromirrors. In use, an optical signal comprising a multiplexed data stream is input into the monolithic reconfigurable optical multiplexer. An optical signal that comprises a modified multiplexed data stream may be output.

Abstract: A grating based optical wavelength demultiplexer that can be used for multiple wavelength bands over a wide wavelength range is presented. The spectral response of the device is cyclic. The free spectral range of the grating is designed to be large enough to contain all the wavelength channels to be demultiplexed within a band but small compared to the overall wavelength window of the network application so that a multiplexed signal within any one of the wavelength bands within the application window can be demultiplexed by the same device. This device, being bidirectional will also operate as a multiplexer. By using such a cyclic design, an organization will not need to stock different parts for each band and thus significantly reduce the inventory cost.

Abstract: A frequency division multiplexing (FDM) node used in optical communications networks provides add-drop multiplexing (ADM) functionality between optical high-speed channels and electrical low-speed channels. The FDM node includes a high-speed system and an ADM crosspoint. The high-speed system converts between an optical high-speed channel and its constituent electrical low-speed channels through the use of frequency division multiplexing and preferably also QAM modulation. The ADM crosspoint couples incoming low-speed channels to outgoing low-speed channels, thus implementing the ADM functionality for the FDM node.

Abstract: A non-disruptive, on-line testing and switchover method and apparatus in a high availability, fibre channel switching environment. In a network having an active switching element, a redundant switching element and a port, one aspect of the present invention provides for verifying a working data path from the port to the redundant switching element, and thereafter verifying a working control path to the redundant switching element. Both verification tests take place without interrupting operation on the network. In addition, another aspect of the present invention provides for recognizing a failure occurrence in the active switching element, and thereafter switching to the redundant switching element with the potential for minimal frame loss.

Abstract: An optical switching device based on stable, non-absorbing optical hard limiters optically switches optical information from an input to a number of outputs based upon address information contained in the optical information. The optical switching device optically detects the location of the address bits in the optical information, optically samples the address bits, optically decodes the sampled address bits, optically activates an output based upon the decoded address bits, and optically outputs the optical information over the activated output.

Abstract: A technique for assigning a wavelength to a new flow in WDM ring networks that minimizes the total number of OE and EO interfaces added to the network is described. A SuperSet comprising thirteen cases representing the spatial relationship between existing wavelengths and the new flow is identified. An OE/EO table identifies for each case in the SuperSet the total number of OE and EO interfaces added. A QoS table identifies an order of priority for selection of a wavelength given a traffic class of the new flow. A mapping of traffic in the network to one of the SuperSet cases is identified and the optimal case that minimizes the total number of OE/EO interfaces added is selected using the OE/EO table. In one embodiment, a wavelength corresponding to the selected case is assigned to the flow. In another embodiment, a determination is made using the QoS table and wavelength grades whether assigning the selected wavelength will result in an acceptable performance for all network traffic.

Abstract: It is an object of the invention to provide an OCDM system which minimizes interferences in the system and maximizes the data throughput in a simple manner. The OCDM system according to the invention is particularly characterized in that the send rate of optical packets to be transmitted in optical channels is different for different optical nodes of the OCDM system. Each node of an OCDM system is allocated one optical channel, for example. Also allocated are the send rates of optical packets to be transmitted in the optical channels, for instance by transmitting an individual frequency to the node.

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: A deformable mirror device is configured so that a deformable mirror of the type driven by electrostatic force is housed in a sealed package made of ceramic or plastic. The package is provided with a transparent window on the entrance and exit side of light. Light is incident on a reflecting surface of the deformable mirror through the window, and the light reflected at the reflecting surface emerges through the window.

Abstract: The OD servers, encoders, NOD servers and CPUs supply voice data, character data and remote control data together with the control information. A transmitter modulates the control information and voice data, etc. by the QPSK modulation method. An infrared ray emitter outputs the modulated infrared ray depending on the modulated signal. A receiving apparatus reproduces acoustic signal from the modulated infrared ray and displays characters and also transmits the signal corresponding to the remote control data to the transmitting apparatus with the infrared ray. An infrared ray detector receives the modulated infrared ray output from the receiving apparatus. Thereby, with this system, the signal, required by the receiving side or suitable for the condition of the receiving side, supplied through many channels can be transmitted without any restriction on the wiring.