Abstract: A repeating apparatus and method using wireless optical transmission is disclosed. The repeating apparatus includes a donor device for transmitting two identical copies of an optical signal by receiving a RF signal from a base station and electro-optic converting the RF signal to an optical signal, and for transmitting a RF signal by receiving two identical copies of the optical signal and optic-electro converting the optical signal to a RF signal; and a coverage device for transmitting a RF signal to a mobile communication terminal by receiving two identical copies of the optical signal from the donor device and optic-electro converting the two identical copies of the optical signal to the RF signal, and transmitting two optical signals to the donor device by receiving the RF signal from the mobile communication terminal and elector-optic converting the RF signal to the optical signal.

Abstract: In an optical wavelength division multiplexed access system, a center unit (OSU) and n optical network units (ONUs) are connected together via a wavelength splitter and optical fiber transmission lines, and downstream optical signals from the OSU to the ONUs and upstream optical signals from the ONUs to the OSU are transmitted in both directions, the wavelength spacing ??d (optical frequency spacing ?fd) of the downstream optical signals is set to twice or more the wavelength spacing ??u (optical frequency spacing ?fu) of the upstream optical signals, each ONU transmits an upstream optical signal whose optical spectral width is twice or more ??u (?fu), and the wavelength splitter spectrum slices the upstream signals transmitted from the ONUs into wavelengths (optical frequencies) whose optical spectral widths are mutually different within ??u (?fu), and wavelength-division multiplexes them and transmits to the OSU.

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: Disclosed is a dense wavelength division multiplexing-passive optical network (DWDM-PON) system utilizing self-injection locking of Fabry-Perot laser diodes, in which output optical signals of different wavelengths are partially fed back by a partial mirror, so as to injection-lock the Fabry-Perot laser diodes, respectively. In accordance with this system, inexpensive Fabry-Perot laser diodes can be used as respective light sources of a central office and optical network units (ONUs). Accordingly, it is possible to minimize the system construction costs, as compared to conventional optical networks.

Abstract: An optical signal transmitter is disclosed that transmits an optical signal with corresponding Wavelength Division Multiplexing (WDM) channels and Time Division Multiplexing (TDM) channels. The transmitter is comprised of a laser, a dispersion system, and a modulator. The laser generates and transmits a narrow laser pulse comprised of a plurality of wavelength channels. The dispersion system broadens the narrow laser pulse into a wide laser pulse. The modulator modulates the wide laser pulse based on an electric modulation signal comprised of a plurality of time slot channels wherein the time slot channels in the electric modulation signal correspond to the wavelength channels in the wide laser pulse respectively. The modulator transfers a modulated wide laser pulse. Channels of the modulated wide laser pulse are hybrid wavelength and time slot channels. The transmitter singularly transmits a WDM optical signal comprised of multiple wavelength channels.

Abstract: A host station apparatus (10) generates band allocation information including identifications of slave station apparatuses (20-1 through 200-n) and types of data to be transmitted by the slave station apparatuses and posts the information to the plural slave station apparatuses (20-1 through 20-n). The plural slave station apparatuses (20-1 through 20-n) identify as to whether or not the band allocation information is band allocation information about the data types of the slave station apparatuses respectively, and when the band allocation information is band allocation information about the data types of the slave station apparatuses, they control to transmit data to the host station apparatus (10) according to the data types represented by the band allocation information.

Abstract: A novel optical time division multiplexing (OTDM) module based on hybrid-integrated optical chips is disclosed. An integrated modulator chip generates optical RZ signal streams which are then interleaved in an integrated time-delay chip to produce an OTDM signal. The integrated modulator chip is coupled and secured to the integrated time-delay chip via a suitable optical index-matching layer or collimating lenses. Such an approach alleviates the stability problems offered by conventional fiber-based OTDM technology and aids in reducing the size and complexity as well as lowering the cost for the assembly. Furthermore, the time-delay chip of the present invention offers fine tuning capabilities thereby allowing for slight adjustments in the interleaving of optical signal streams when non-standard data transmission rates are required.

Abstract: The optical fiber-based communication system comprises a distribution optical fiber that extends proximately to a plurality of end users, and tap-off modules coupled to the distribution optical fiber at intervals along its length. Each of the tap-off modules includes a port in optical communication with the distribution optical fiber. The optical fiber-based communication system additionally comprises a branch optical fiber connected to the port of each of at least some of the tap-off modules and that extends to a corresponding one of the end users.

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: 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: Optical communication systems include a central station that encodes data transmitted to multiplexing (mux) stations or user stations. The central station also decodes data received from the mux stations or user stations. Encoding and decoding are performed using codes, such as composite codes, that designate sources and destinations for data. The mux stations, user stations, and the central station have address encoders and decoders that use, for example, fiber Bragg gratings to encode or decode optical signals according to a code such as a composite code derived by combining codes from one or more sets of codes. A passive optical network comprises one or more levels of mux stations that use such address decoders and encoders to receive, decode, and encode data for transmission toward a central station or a user station.

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 selection module for use in an optical signal switch comprises a spatial selector comprising a plurality of inputs each receiving a wavelength division multiplexed optical signal comprising a plurality of channels each associated with a separate wavelength, an output delivering a single signal selected from the plurality of wavelength division multiplexed signals, and a plurality of spectral selectors each selecting a channel from a plurality of channels of the signal selected by the spatial selector.

Abstract: The access node for optical networks with variable access wavelengths can be connected to user devices via respective first optical conductors and can be connected to the optical network via second optical conductors. The novel access node has light sources which emit at the wavelengths defined in the optical network. The light of the light sources can be modulated in the user devices. This prevents that in each case a light source which must be able to emit light of a different wavelength in a dynamic optical network or the wavelengths of which must be subsequently converted must be arranged in the individual user devices. In addition, it also prevents circuit boards leading to a high logistical expenditure having to be provided in the user devices. Accordingly, according to the invention, it is possible to construct the individual user devices without light sources. This considerably simplifies their construction and the method of use.

Abstract: A synchronized optical clocking signal is provided to a plurality of optical receivers by providing a layer of a high absorption coefficient material, such as SiGe or Ge, on a front surface of a low absorption coefficient substrate, such as silicon. Diodes are formed in the germanium containing layer for receiving an optical signal and converting the optical signal into an electrical signal. An optical clocking signal is shined on the back surface of the silicon substrate. The light has a wavelength long enough so that it penetrates through the silicon substrate to the germanium containing layer. The wavelength is short enough so that the light is absorbed in the germanium containing layer and converted to the electrical clocking signal used for neighboring devices and circuits. The germanium concentration is graded so that minority carriers are quickly swept across junctions of the diodes and collected.

Abstract: A passive optical star coupler, and associated method of operation arranged to transmit signals received at any input port to all output ports other than an output port associated with the input port. In this way all received signals are broadcast to all connected network equipment with the exception of the transmitting equipment.

Abstract: The light beam emitted from a variable wavelength light source element 2 is partly directly monitored in a second detector 2 for automatic power control in an APC circuit 14, and is also partly passed through a wavelength filter 5 with the transmittance thereof varying with the wavelength and monitored in A first detector 65. Automatic frequency control is performed in an AFC circuit 15 while detecting wavelength variations by using the filter output and the direct monitored output. Thus, the construction is extremely simplified, while reducing the size and cost.

Abstract: A synchronization system in accordance with the principles of the invention includes a central synchronizing management unit, at least one synchronization distribution unit, and at least one network element. Each synchronization distribution unit receives synchronization and management information from the central synchronization management unit. This information may be transmitted directly from the central synchronization management unit, or it may be transmitted though another synchronization distribution unit in a group of a daisy-chained synchronization distribution units. The daisy-chained arrangement employs both active and passive optical paths. The central synchronizing management unit may query any synchronization distribution unit within the system to obtain performance statistics.

Abstract: A passive optical network (PON) including an optical line termination (OLT) and a plurality of optical network units (ONUs) which are connected. The optical line termination includes a band setting control section; an upstream control cell receiving section; a use right transmitting section; and a downstream control cell transmitting section. Each of the plurality of optical network units includes a downstream control cell receiving section; a use right acquisition determining section; and an upstream control cell transmitting section.

Abstract: A method and apparatus for determining the dispersion characteristics of minimum phase filters using substantially only an amplitude response of a minimum phase filter under test includes fitting an amplitude spectrum of the minimum phase filter with a substantially straight line curve, and determining the dispersion characteristics of the minimum phase filter using the straight line curve and the relationships determined by the inventors. Various inventive equations determined by the inventors representative of the relationship between an amplitude response of a minimum phase filter and the dispersion characteristics of the minimum phase filter are used for determining the dispersion characteristics of the minimum phase filter.

Abstract: Multiple dense wavelength division multiplexing (DWDM) signals are superimposed on a single channel of a multiplexed signal in a coarse wavelength division multiplexing (CWDM) system. The DWDM signals may be superimposed on the CWDM spectrum in a metro area network that has legacy optical components that are otherwise designed for use with CWDM signals. This system increases the data transmission rates that can be achieved over an existing network that has less expensive CWDM optical components. The system also provides a scalable solution for increasing data transmission capacity in new networks.

Abstract: A subscriber optical distributor and method for a broadcasting-telecommunications convergence service over an FTTH (Fiber To The Home) optical transmission network. An optical transceiver receives a TDM broadcasting-telecommunications optical signal, converts the optical signal to an electrical signal, and converts an uplink electrical signal received from a subscriber to an optical signal. A broadcasting/telecommunications signal distributor receives the electrical broadcasting-telecommunications signal and separates the received electrical signal into a broadcasting signal and a telecommunications signal. A broadcasting interface interfaces the broadcasting signal received from the broadcasting/telecommunications signal distributor. A telecommunications interface transmits the telecommunications signal received from the broadcasting/telecommunications signal distributor, and provides the uplink signal to the optical transceiver.

Abstract: For an optical network including photonic nodes and photonic/optical node, we introduce a concept of photonic cell. Each optical node with DWDM optics forms a base node for a photonic cell. Nodes are members of a photonic cell if they are within optical reach of the base node. Every other optical node with DWDM optics within the photonic cell also serves as a base node for its own photonic cell. By mapping the network to overlapping photonic cells, route alternatives can be determined by using the cell membership tables as a constraint rather than having to invoke complex link engineering computations as part of the routing method.

Abstract: A single device for amplifying and multiplying an optical signal is presented. The device is an InP-semiconductor-based amplified multimode interferometer. The three main sections of the device are an input port, an interference and amplification region and N output ports. The input port is a single channel waveguide. The interference and amplification section supports a large number of modes which interfere with one another. By carefully choosing the length of the interference/amplification region to correspond to the constructive interference condition for N equally spaced channel modes, we can reproduce N amplified signals. In an alternate embodiment, by shaping the gain region into a cross pattern, corner reflections and consequent side channel signal distortion in the output can be minimized.

Abstract: A system for checking the correct operation of a wavelength filter comprising a wavelength filter comprising a first selectively reflective element (SRE) for reflecting a first signal of a first wavelength and a second SRE for reflecting a second signal of a different wavelength. The system also detects the second signal reflected by the second selectively reflective element.

Abstract: An optical network has an optical splitter connected to (1) a working optical subscriber unit (OSU) of a working circuit via a working optical fiber, (2) a protection OSU of a protection circuit via a protection optical fiber, and (3) one or more optical network terminals (ONTs), where the protection OSU has a protection burst mode receiver (BMR) configured to receive an upstream optical signal from the optical splitter. The algorithm determines whether the protection OSU is functioning improperly. A reset pulse is applied at the protection BMR at a particular timing position and an attempt is made to interpret the current upstream cell received at the protection BMR. This process is repeated using different timing positions for the BMR reset pulse until the current upstream cell is correctly interpreted, e.g., based on the correct identification of an ATM header error correction (HEC) byte in the upstream cell.

Abstract: An optical network has an optical splitter connected to (1) a working optical subscriber unit (OSU) of a working circuit, (2) a protection OSU of a protection circuit, and (3) one or more optical network terminals (ONTs), where an ONT has (i) a working line termination (LT) unit of the working circuit and connected to the optical splitter via a working optical fiber and (ii) a protection LT unit of the protection circuit and connected to the optical splitter via a protection optical fiber. The present invention enables fast protection switching from the working circuit to the protection circuit. The arrival times of corresponding downstream cells are measured at both the working and protection LT units of the ONT, and information related to the arrival times is transmitted from the ONT to the protection OSU.

Abstract: An optical superposition network that utilizes a time division multiplexing (TDM) protocol includes a first optical transmitter, a second optical transmitter and a receiver. The first optical transmitter transmits information in a tertiary mode during a time slot. The second optical transmitter transmits information in a tertiary mode during a different time slot. The information transmitted across the optical superposition network has an approximately constant average intensity such that the receiver can utilize a single decision threshold for the information received from the first and second optical transmitters.

Abstract: A balun is constructed from a parallel pair of lines (coaxial or bifiler) that are bent to form a U-shape including a more curved (bent) section with two ends each of which are connected to a respective less curved (straight leg) section. One or more single hole ferrite beads are threaded over each respective pair of less curved sections of the pair of lines.

Abstract: A method and system deliver multiple-band broadcast services in a network such as a wavelength division multiplexed passive optical network. In the transmitter and/or receiver of such a system, filters are cascaded to stack data corresponding to different services within different free spectral frequency ranges of an optical transmission signal. Each filter is used to select a portion of a free spectral frequency range to be delivered to a user node. Each transmitter filter confines the output from spontaneous emission sources to a desired spectral region. The cascaded filters can also combine multiple spectra and/or separate combined broadcast spectrum. The method can also be used to partition the output from a broadband spectral source into different portions in the spectral domain.

Abstract: A high-speed access data network in which upstream and downstream traffic is logically or physically separated. The network can use the Ethernet media access control (MAC) layer protocol over distances that are much larger than conventionally possible with the Ethernet MAC layer protocol. In a configuration including a central office and multiple subscribers, the central office is removed from the collision domain, which can be made relatively small, without limiting the distance between the central office and the subscribers. The downstream data rate is not limited by the size of the collision domain and can thus be made almost arbitrarily large. Furthermore, by allowing a smaller collision domain, greater upstream data rates can be used. It is thus possible to use ubiquitous and inexpensive Ethernet LAN technology in highly cost-sensitive applications such as residential broadband access.

Abstract: A fiber-to-the-home (FTTH) system transmits forward and reverse optical signals, such as video, voice, and data signals, via optical fiber, and includes a plurality of home network units. The home network units include an FTTH optical receiver for receiving at least one of the video, voice, and data signals. A triplexer distinguishes and separates the video, voice, and data signals, wherein the video signals have a first wavelength and the voice and data signals have a second wavelength. The voice and data signals are provided to the home network unit for further processing. The triplexer provides an electrical signal to the amplifier stages. The amplifier stages include a preamplifier stage and a postamplifier stage. A gain control circuit automatically adjusts the gain of the video signal based upon the input power level to the FTTH optical receiver. Additionally, a tilt network performs level compensation for externally located coaxial cable.

Abstract: A wireless communication system comprises a base station controller and a base station interface connected to the base station controller by a central optical fiber. The base station interface may include a flexible wavelength router. At least one base station is connected to the base station interface, and the central optical fiber carries at least one communication channel associated with an optical signal having one of a plurality of wavelengths. The base station interface selectively provides a communication path between the base station controller and at least one base station using at least one communication channel.

Abstract: A communication system between head-ends and end-users is provided which expands bandwidth and reliability. A concentrator receives communication signals from a head-end and forwards the received communication signals to one or more fiber nodes and/or one or more mini-fiber nodes. The concentrator demultiplexes/splits received signals for the mini-fiber nodes and the fiber nodes and forwards demultiplexed/split signals respectively. The mini-fiber nodes may combine signals received from the head-end with loop-back signals used for local medium access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and/or fiber node and transmitted to the concentrator. The concentrator multiplexes/couples the mini-fiber node and the fiber node upstream signals and forwards multiplexed/coupled signals to the head-end.

Abstract: An apparatus and method is disclosed for protecting access to a shared medium in an optical communications system which has plural remote terminals coupled to a central terminal over the shared medium. According to one aspect, if an optical transmitter for an individual remote terminal is active for a first prescribed time interval when it has not been enabled for such transmission, the optical transmitter is disabled. According to another aspect, the continuous time that an individual terminal is enabled to transmit onto the shared medium is monitored. If the enabled transmission for the individual terminal exceeds a second prescribed time interval, the optical transmitter for the individual terminal is disabled.

Abstract: An optical subscriber line terminal unit and a state transition control method are provided which are capable of stabilizing operation. State information storing means, which is a nonvolatile memory, stores state information about the unit. Startup preparatory state shifting means causes a shift to a startup preparatory state at startup. Flag setting means sets an emergency stop state flag during the period of the startup preparatory state if it is judged based on the state information that a state before the startup is an emergency stop state. State transition control means causes a shift from the startup preparatory state to the emergency stop state if the emergency stop state flag is set, and causes a shift from the startup preparatory state to an initial state if the emergency stop state flag is not set.

Abstract: A delay adjustment unit and optical network unit which efficiently adjust the delay time of upstream data to improve the quality of data transmission services. Upstream transmission data is segmented into small data blocks. A downstream receiver receives control information on which upstream data blocks are granted or not granted to the unit. It also received an equalization delay update request that commands the unit to update its current equalization delay parameter. When this equalization delay update request is received, a delay adjustment controller controls the delay of each data block, depending on whether the transmission of each subsequent data block is granted. An upstream transmitter then transmits the granted data blocks with the adjusted delay times.

Abstract: A wavelength multiplexed signal transmitted through an inter-node transmission path is demultiplexed to a wavelength band by a first optical demultiplexer and after having its path changed by a first matrix switch, the obtained signal is again wavelength-multiplexed by a first optical multiplexer and then output to the inter-node transmission path. On the other hand, signals to be subjected to processing on a wavelength basis are demultiplexed on a wavelength basis by a second optical demultiplexer capable of demultiplexing an arbitrary wavelength band through a link and after having their paths changed by a second matrix switch, the obtained signals are again multiplexed to a wavelength band by a second optical multiplexer, subjected to the same processing as that of the above-described wavelength band and output to the inter-node transmission path.

Abstract: A method for checking a ring optical network line for data transmission between a plurality of network subscribers in a motor vehicle, wherein one network subscribers carries out a master function, wherein, apart from the optical network line, there is a further communication line which has a star structure. The network subscribers having the master function is arranged in the centre of the star structure and is connected directly via the communication line to every other network subscribers. The optical network line is checked by the network subscriber having the master function outputting a start signal to the individual network subscribers. The individual network subscribers acknowledge the start signal for the network subscribers the master function via the communication line. After the start signal, the network subscriber having the master function outputs an initialization signal via the optical network line.

Abstract: A method and system provide alternative communication paths utilizing overhead channels available on the communication network to permit isolated offices to have access to a data network and hence a remotely located monitor/controller via an office that has direct access to such a data network. In addition, the system permits an arrangement of subnetworks which allows a first subnetwork to act as a back-up or redundant path for obtaining alarm and status information regarding a second subnetwork via overhead channels available on the communication path in the first subnetwork.

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.