4510results about "Wavelength-division multiplex systems" patented technology

A hierarchical network management system (NMS) in which a plurality of NMS managers, each responsible for different portions or aggregations of a communications network, are logically arranged in a tree structure. The NMS managers are further organized into various sub-groups. The NMS managers within each sub-group monitor the status of one another in order to detect when one of them is no longer operational. If this happens, the remaining operational NMS managers of the sub-group collectively elect one of them to assume the responsibility of the non-operational NMS manager. The NMS is thus "self-healing" in the sense that one NMS manager can dynamically, without operator intervention, assume the responsibilities for another NMS manager.

A distributed antenna system (DAS) includes a multiple-input and multiple-output (“MIMO”) base station configured to output at least a first and second signal, and a hybrid coupler coupled thereto, the coupler configured to receive the first and second signal from the MIMO base station on respective first and second ports and provide an output signal on at least one output port, the output signal including at least a portion of the first signal and at least a portion of the second signal. The DAS further includes a master unit communicating with the coupler and configured to receive at least the output signal, and at least one remote unit communicating with the master unit and configured to communicate the output signal to a device.

The system includes, at least first and second antennas receiving first and second radio frequency signals, and a multiplexing system converting the first and second radio frequency signals to first and second optical signals and multiplexing the first and second optical signals for transmission over the optical fiber. A central processing base station is adapted for connection to the optical fiber. The central processing base station demultiplexes the first and second optical signals from the optical fiber, converts the first and second optical signals into the first and second radio frequency signals, and processes the first and second radio frequency signals to obtain information signals. In another embodiment, a conductor such as a coaxial cable replaces the optical fiber, and the multiplexer multiplexes the first and second radio frequency signals onto the conductor. In a further embodiment, the central processing base station uses the same techniques to send signals to an access point for transmission.

Systems and methods for providing broadband communication are provided. An optical fiber node may be coupled to a source component. The optical fiber node may receive, from the source component, a downstream light signal via at least one input optical fiber, and transmit the downstream light signal to a plurality of output optical fibers. A tap device may be coupled to the optical fiber node via at least on optical fiber. The tap device may receive the downstream light signal via the at least one output optical fiber, convert the downstream light signal into a radio frequency downstream signal, and transmit the radio frequency downstream signal to a plurality of cable lines. The plurality of cable lines may be coupled to one or more customer premises.

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.

A communication system for distributing information via a network to one or more subscribers includes a multi-port switch, one or more radio frequency (RF) modems coupled to respective ports of the switch, a combiner and a transmitter. The switch forwards source information to the RF modems based on address information. Each RF modem modulates and up converts information from the switch to an RF signal within a respective subscriber channel of the television broadcast spectrum. Each channel is assigned to one or more subscribers, and each subscriber is allocated unshared bandwidth. Each channel may be further divided into unshared bandwidth increments, so that multiple subscribers may share a single channel. The combiner combines modulated information from each RF modem into a combined signal and the transmitter transmits the combined signal to the subscribers via the network. An HFC network including a distribution point and one or more optical nodes is contemplated, each optical node serving a particular geographic area via a corresponding coaxial cable. Each subscriber destination includes a gateway device or the like that is tuned to a corresponding channel to retrieve source information from that channel, and to deliver the information to one or more local subscriber devices. The gateway further includes converters, a modulator and an up converter to receive and transmit subscriber information upstream to the distribution point. The gateways and an address resolution server enforce point to point communications. A bandwidth manager allocates bandwidth and monitors bandwidth usage.

A network is provided that includes a plurality of antennas coupled over the network to a plurality of base stations. The network can be optical or constructed with RF microwave links. The base stations are configured to provide cellular transmission. A plurality of links couple the plurality of antennas and the plurality of base stations. At least one link of the plurality of links provides multiple transmission paths between at least a portion of the base stations with at least a portion of the antennas. In one implementation, at least one link of the plurality of links is shared by at least two cellular operators on different transmission paths. In another implementation, at least a portion of the plurality of base stations are in a common location and at least a portion of the antennas are geographically disbursed.

Methods and apparatus for generating and processing a signal are disclosed. The signal may comprise a plurality of mutually orthogonal subcarriers constituting a plurality of bands. The signal may be either an optical or a radio frequency signal.

One embodiment provides a system for power saving in an Ethernet Passive Optic Network (EPON). The system includes an optical line terminal (OLT), an optical network unit (ONU), a traffic-detection module configured to detect status of traffic to and from the ONU, and a power-management module configured to place the ONU in sleep mode based on the detected traffic status. The ONU includes an optical transceiver that includes an optical transmitter configured to transmit optical signals to the OLT and an optical receiver configured to receive optical signals from the OLT.

A network element is configured to provide a distributed data center architecture between at least two data center locations. The network element includes a plurality of ports configured to switch packets between one another; wherein a first port of the plurality of ports is connected to an intra-data center network of a first data center location and a second port of the plurality of ports is connected to a second data center location that is remote from the first data center location over a Wide Area Network (WAN), and wherein the intra-data center network of the first data center location, the WAN, and an intra-data center network of the second data center location utilize an ordered label structure between one another to form the distributed data center architecture.

The invention relates to a method of activating an optical communication system comprising a plurality of optical amplifiers having an optical amplifier, between optical transmission lines in which wavelength-division multiplex optical signals are transmitted. The method comprises steps of: generating a desired slope in a desired wavelength range of a gain wavelength curve of the optical amplifier; adjusting an output of the optical amplifier to a desired output level; performing the above two steps in a plurality of optical repeater stations, the steps being carried out in sequence from the first to the last optical repeater stations; and adjusting a level in each optical signal in the wavelength-division multiplex optical signal so as to have substantially constant optical signal-to-noise ratios in the optical signals to be received. Activating the optical communication system according to this procedure allows proper execution of gain slope compensation, output control, and pre-emphasis control.

The present invention relates to an optical fiber access network, and more particularly, to a multi-purpose optical fiber access network capable of accepting all services provided by hybrid wireline/wireless access network.

According to the present invention, in an optical fiber access network of double star structure where a central office/headend and several optical network units are connected through a splitting/combining device, a multi-purpose optical fiber access network capable of accepting not only wired telephone service, wired CATV and wired data service but also various kinds of wireless services including LMDS, WLL, PCS and so forth, in which LMDS local wireless base station is located in a place adjacent to the splitting/combining device, WLL local wireless base station is located in a place adjacent to the splitting/combining device, optical network unit connects the conventional wired network composed of said optical fiber access network, twisted pair and coaxial cable, telephone service, data service and CATV service are provided through the optical network unit and PCS local wireless base station is located in a place adjacent to the optical network unit, is provided.

Integrated wired and wireless wavelength division multiplexing passive optical network (WDM PON) apparatus using a light source mode-locked to fed incoherent light includes: a fed light generator for providing fed light for up/downstream signals via a broadband light source emitting an incoherent optical signal; a central office (CO) for receiving, mode-locking, and downstream-optical-transmitting the incoherent optical signal generated by the fed light generator and receiving and optical-detecting an upstream optical signal transmitted from a subscriber unit; and the subscriber unit for receiving, mode-locking, and upstream-optical-transmitting the incoherent optical signal generated by the fed light generator and receiving and optical-detecting a downstream optical signal transmitted from the CO, wherein a wired optical transmitter for transmitting a baseband wired signal and a wireless optical transmitter for transmitting a high frequency radio frequency (RF) signal are comprised for up/downstream optical transmission of the CO and the subscriber unit.

An optical coupling device including: at least a first input port for delivering an optical input signal beam that includes a plurality of wavelength channels; at least a first optical output port for receiving an optical output signal beam; a wavelength dispersion element for spatially separating the plurality of wavelength channels in the optical input signal beam to form a plurality of spatially separated wavelength channel beams; an optical coupling device for independently modifying the phase of each of the spatially separated wavelength channel beams such that, for at least one wavelength channel beam, a selected fraction of the light is coupled to the first output port and a fraction of the light is coupled away from the first output port.

An optical line terminal, a passive optical network and a radio frequency signal transmission method in the communication technical field are provided. The passive optical network comprises: an OLT, an ODN and at least one ONU. The OLT comprises: at least one transmitting unit, which provides one dedicated downstream optical carrier and two dedicated upstream optical carriers for ONU; the two dedicated optical carriers for ONU are configured to carry ONU upstream radio frequency signals; a multiplexing/demultiplexing unit; and at least one receiving unit which obtains the upstream signal from the demultiplexed upstream optical signal. The bandwidth of wireless access network is enhanced, and the design of ONU is simple.

The present invention discloses a low-cost light source for optical transmission systems and optical networks based on wavelength-division multiplexing (WDM) technology. A light source in accordance with the present invention is implemented by externally injecting a narrow-band incoherent light into a Fabry-Perot laser diode (F-P LD). After injection of narrow-band incoherent light, the output of F-P LD becomes wavelength-selective rather than multi-mode and the output wavelength of F-P LD coincide with the peak wavelength of the injected incoherent light. Multi-channel WDM light sources according to the present invention can be implemented using a single broadband incoherent light source and plurality of F-P LDs. An optical transmission system for upstream signal transmission in an passive optical network using the light source according the present invention is also disclosed.

A radio-over-fiber (RoF) wireless picocellular system adapted to form an array of substantially non-overlapping individual picocells by operating adjacent picocells at different frequencies is operated to form one or more combined picocells. The combined picocells are formed from two or more neighboring picocells by the central head-end station operating neighboring picocells at a common frequency. Communication between the central head-end station and a client device residing within a combined picocell is enhanced by the availability of two or more transponder antenna systems. Thus, enhanced communication techniques such as antenna diversity, phased-array antenna networks and multiple-input/multiple-output (MIMO) methods can be implemented to provide the system with enhanced performance capability. These techniques are preferably implemented at the central head-end station to avoid having to make substantial changes to the wireless picocellular system infrastructure.

A loss-less, optical add/drop multiplexer according to the present invention includes a rare earth-doped fiber amplifier integrated with a wavelength-selective fiber path coupled between two directional optical transfer devices for selectively adding and dropping optical signals from a multi-wavelength signal, such as a wavelength division multiplexed optical signal. One or more fiber gratings are disposed along the length of the rare earth-doped fiber amplifier or between segments of the rare earth-doped fiber so that at least one grating is used for reflecting each optical signal that is expected to be added to or dropped from the multi-wavelength optical signal. By using this configuration, appropriate amplification is provided to compensate for losses in the add, drop, and through paths.

The present wavelength multiplexed optical system includes a multimode optical fiber that transmits wavelength multiplexed optical signals and a plurality of multimode modal dispersion compensation optical fibers. Each modal dispersion compensation optical fiber can transmit one of the multiplex wavelengths, and each modal dispersion compensation optical fiber has an optimized index profile such that the modal dispersion for the transmitted wavelength is approximately inversely equal to the modal dispersion induced in the multimode optical fiber. The wavelength multiplexed optical system facilitates an increased bitrate without reducing bandwidth.

A SW (70) receives an Ethernet® signal from an outside of areas E and F. The SW (70) selects and outputs the obtained Ethernet® signal to any one of APs (91a to 91e) in accordance with a network structure managed by the SW (70). The AP (91a to 91e) converts the Ethernet® signal to an electrical signal type wireless LAN signal, which is in turn output to a main station (10). The main station (10) frequency-multiplexes the signal output from each of the APs (91a to 91e), and converts the signal to an optical signal, which is in turn output to sub-stations (20a and 20b) The sub-station (20a and 20b) transmits the signal transmitted from the main station (10) to a terminal in the form of a wireless radio wave. Thereby, when a plurality of communication areas are present, the accommodation capacity of an AP can be effectively utilized in each communication area.

A wavelength division multiplexed optical network has a restoration process to re-route one or more of the wavelengths, by dynamically determining possible restoration routes, and re-routing each wavelength along a chosen one of the possible restoration routes. A distributed dynamic search for restoration routes down to the optical layer, for wavelengths, gives faster and more scalable restoration than reconfiguring routing tables and enables much better utilisation of bandwidth than using predetermined restoration paths.

A radio over fiber link apparatus for transmitting/receiving radio frequency up/downlink signals in a TDD mobile communication system. The radio over fiber link apparatus includes a center site for receiving radio frequency signals from an access point of the mobile communication system. The center site has a first electro-optic converter for converting the radio frequency signals into optical signals, bias control of the first electro-optic converter being performed based on the switching of TDD signals; and a remote for transmitting the radio frequency signals to a mobile communication terminal through an antenna. The remote site has a first photoelectric converter for converting the optical signals transmitted through an optical fiber from the center site into radio frequency signals.

Methods and apparatus are described for distribution optical elements and compound collector lenses for a broadcast interconnect. An apparatus includes a broadcast optical interconnect including: a plurality of nodes positioned to define a node array, each of the plurality of nodes having at least one optical signal emitter and a plurality of optical signal receivers positioned to define a receiver array that substantially corresponds to the node array; and a plurality of optics optically coupled to the array of nodes, the plurality of optics positioned to define an optics array that substantially corresponds to the node array and the receiver array, each of the plurality of optics including at least one optical distributing element and an optical collecting element, wherein an optical signal from the optical signal emitter is fanned-out by the at least one optical distributing element of one of the optics and broadcast to one of the plurality of receivers of all of the plurality of nodes by the optical collecting element of all of the plurality of optics.

A visible ray communication system and method that improve transmission rate and remove an influence of inter-color interference to improve the communication quality. A transmission apparatus included in the visible ray communication system allocates each carrier signal component of an OFDM signal, which is modulated into transmission information, to a plurality of LEDs of different colors. The information is added to a combination of a carrier frequency and an LED wavelength, when a carrier signal is allocated to an, in addition to each carrier signal being modulated into the information.

A wavelength division multiplexed optical access network including a central office for multiplexing first optical signals used for transmitting a high-speed wire data service to a subscriber side and second optical signals used for transmitting a wireless data service to a remote subscriber terminal, a remote node connected to the central office through an optical fiber and for de-multiplexing a multiplexed optical signal received from the central office, a plurality of subscribers connected to the remote node, each subscriber receiving a first optical signal having a corresponding wavelength from among the de-multiplexed first optical signals, and a plurality of radio access units connected to the remote node, each radio access unit converting a second optical signal having a corresponding wavelength from among the de-multiplexed second optical signals into a wireless electric signal and wirelessly transmitting the wireless electric signal.

A method and architecture for secure transmission of data within optical-switched networks. In one embodiment, the optical switched network comprises a photonic burst-switched (PBS) network. Under various schemes, security keys including encryption and decryption keys are generated by edge nodes and the decryption keys are distributed to other edge nodes in a PBS network. In one embodiment, the security keys are dynamically generated by a trusted platform module (TPM). A source edge node uses its encryption key to encrypt selected data bursts to be sent to a destination edge node via a virtual lightpath coupling the source and destination edge nodes. Security data are embedded in a control burst header indicates to the destination node whether corresponding data bursts sent via the virtual lightpath are encrypted. The security data also includes the decryption key and may also identify an encryption/decryption algorithm to be used. In some embodiments, public key infrastructure facilities are used in conjunction with employment of private and public keys and digital certificates.

A fully meshed telecommunications network based on an optical core transport network having a plurality of optical nodes is described. An electronic edge switch is connected to an optical node and dedicated channels are established between all the possible pairs of electronic edge switches through their associated optical nodes and the optical core transport network. Connection paths are set up using a channel or channels between a pair of electronic edge switches which perform major functions concerning connection routes, including rate regulation, path establishment, etc.

Apparatus and methods that utilize tunable elements to provide for selective wavelength tuning of a light beam. The apparatus comprises a first tunable wavelength selection element having a first adjustable free spectral range, a second tunable wavelength selection element having a second adjustable free spectral range, with the first and second tunable wavelength selection elements configured to define a tunable joint transmission peak. The first and second tunable wavelength selection elements respectively define first and second pluralities of tunable transmission peaks, wherein respective ones of each of the first and second plurality of transmission peaks are aligned to obtain a joint transmission peak that may be adjusted by tuning the wavelength selection elements. The free spectral ranges of the wavelength selection elements are configured to enable a Vernier tuning effect.

There is provided an electro-optical component comprising (a) a substrate, (b) a phase-variable element carried on the substrate, (c) a memory carried on the substrate for storing data representative of a phase state for the phase-variable element; and (d) a controller carried on the substrate, for utilizing the data and setting the phase state for the element. There is also provided an electro-optical component comprising (a) a substrate, (b) a phase-variable element carried on the substrate, and (c) a circuit carried on the substrate for computing and applying a phase state for the phase-variable element.

Modular WSS-based Communications system with colorless and network-port transparent add/drop interfaces is described herein. According to certain aspects of the invention, equipment architecture is provided that enables a linear, ring, and mesh optical network. The embodiments of the invention are primarily on how to add and drop signals at a node of the network. The embodiments of the invention are based on the use a wavelength selective switch (WSS), which is an emerging component technology. Other methods and apparatuses are also described.