6121results about "Transmission monitoring/testing/fault-measurement systems" patented technology

Methods and systems for monitoring a plurality of different optical signals from a single source of such signals, where each such different optical signal is spatially separated from other such signals and directed to different detectors or locations upon a single detector, which direction is generally accomplished through the use of a small numberof optical components and/or manipulations.

To provide an improved information processing apparatus and a method for controlling the same, which enables to smoothly transfer data, such as processed results obtained from execution of an application program, an HTML file acquired from a Web server in accordance with the TCP/IP protocol or the like, to an external device (PDA) by using an infrared communication function. The disclosed information processing apparatus periodically accesses a predetermined server machine (e.g., a Web server) to acquire a desired file (e.g., an HTML file). This file acquisition operation is carried out without the involvement of operations of an infrared transceiver. In other words, the information processing apparatus attempts to continually perform caching of the most recent download data. As a result, when the PDA as an external device is set into an infrared communication mode and a user simply holds the PDA to a station discoverable region of the information processing apparatus, a connection between them is established, thereby enabling the PDA to receive the most recent data.

Polarization mode dispersion in an optical signal transmitted through a waveguide of a communications system is compensated by separating the dispersed signal into components corresponding to principal polarization states. The components are delayed by respective delays differing by a delay increment which is controlled to correspond to the dispersion delay and the delayed components are recombined to provide a dispersion compensated optical output signal. Each of the delays is provided by an chirped Bragg reflector forming part of a delay line, the Bragg reflectors comprising optical fibres with chirped intracore index gratings. Transducers or temperature controllers acting on one of the fibres allows dimensional control of the grating periodicity such that the position of Bragg reflection is variable. Wavelength division multiplexed optical signals are compensated using sampled gratings which allow a common Bragg reflection position for each wavelength.

A fiber drop terminal may include a housing having an outer surface containing a plurality of receptacles. The housing may include a lower surface and an inner cavity. The fiber drop terminal may include a fiber storage cavity occupying a portion of the inner cavity. The storage cavity may store a plurality of fiber coils at an angle.

A system and method for providing multi-services within a communication network according to various exemplary embodiments can include storing, in a database of a computer, user-defined sets of rules and instructions for providing multi-services to end user devices connected to a communication network comprising a Hybrid Fiber-Wireless (HFW) network having policy management capabilities. The system and method can receive, at one or more processors, the user-defined sets of rules and instructions from a plurality of end users via a plurality of end user devices. The system and method can configure a virtual network for each end user within the communication network using the policy management capabilities based on the user-defined sets of rules and instructions provided by each end user. The user-defined sets of rules and instructions define provisioning and delivery of resources and services provided by the communication network to the end user.

A technique for monitoring optical power in a fiber array unit having a plurality of optical transmission waveguides terminating at an edge thereof for carrying optical signals to and/or from a PLC. A tapping filter is placed within a slit formed in the substrate and interrupting the transmission channels, thereby tapping at least some of the optical power from the channels and directing the tapped optical power toward respective photodetector channels for detection, while allowing other optical power to continue transmission in the at least one channel of the fiber array unit.

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.

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 centralized optical-fiber-based wireless picocellular system includes one or more service units at a central head-end station. The one or more service units are optically coupled to one or more transponders via respective one or more optical fiber RF communication links. The transponders are each adapted to provide within the associated picocell electromagnetic RF service signals from different service units, and receive electromagnetic RF service signals from any client device within the picocell. The service signal from the particular client device is sent over the optical fiber RF communication link back to one or more service units. The transponders are arranged along the length of one or more optical fiber cables, which can be distributed throughout a building infrastructure. This creates a picocellular coverage area that provides a number of different wireless services relative to the building infrastructure. The service units can generate the electrical service signals, pass such signals to and from one or more outside networks, and/or coordinate the delivery of the signals between client devices within the picocellular coverage area.

The invention is a novel method and apparatus for controlling the flow of traffic between a host digital terminal (HDT) and a plurality of optical network units (ONUs). Each ONU is connected to the HDT by optical fiber and to a plurality of subscribers by a respective plurality of subscriber drops (typically pre-existing copper twisted pairs). The bandwidth on the fiber, although large, is usually inferior to the total bandwidth that can be transmitted across the subscriber drops. Therefore, both upstream and downstream traffic may become congested at various "choke points" under certain circumstances of usage. Ordinarily, the data is buffered at the choke points, leading to the installation of large queues within each ONU. This solution is not only expensive, but is inadequate since the required queue size is dependent on the maximum transaction size, which has no hard upper bound. In contrast, the present invention provides a traffic shaper located in the HDT, which gives centralized control of the traffic flowing to and from the ONUs. Consideration of the priority and destination of each traffic cell is taken into account by the traffic shaper to ensure that the capacity of the fiber and of the individual drops is never exceeded, irrespective of the transaction sizes, thereby eliminating the need for costly buffers in the outside plant. Any maintenance or repairs of the traffic shaper can be easily effected without field visits, due to its centralized location.

A phase shift unit provides a prescribed phase difference (π/2, for example) between a pair of optical signals transmitted via a pair of arms constituting a data modulation unit. A low-frequency signal f₀ is superimposed on one of the optical signals. A signal of which phase is shifted by π/2 from the low-frequency signal f₀ is superimposed on the other optical signal. A pair of the optical signals is coupled, and a part of which is converted into an electrical signal by a photodiode. 2f₀ component contained in the electrical signal is extracted. Bias voltage provided to the phase shift unit is controlled by feedback control so that the 2f₀ component becomes the minimum.

An optical-fiber-network (OFN) radio-frequency identification (RFID) system for deploying and/or maintaining and/or provisioning service and/or locating faults in an OFN. The system includes a plurality of OFN components, and at least one RFID tag that includes RFID tag data that has at least one property of the OFN component associated with the RFID tag. The RFID tag data is written to and read from the RFID tags using one or more mobile RFID readers either prior to, during or after deploying the OFN components. An OFN-component-data database unit is used to store and process the RFID tag data and is automatically updated by the one or more mobile RFID readers. This allows for different maps of the OFN to be made, such as an inventory map and a maintenance map, and for the maps to be automatically updated. The OFN-RFID system allows for mobile automated operations and management of OFN components by service personnel, and provides for faster and more accurate OFN system deployment and maintenance.

The present disclosure provides systems and methods for making latency measurements and using these measurements in routing in optical networks. In an exemplary embodiment, a method is defined whereby two nodes sharing a line automatically determine whether both nodes are capable of making a latency measurement and then which node will initiate and which node participates in making the latency measurement. In another exemplary embodiment, an on-demand latency measurement may be made between any two arbitrary nodes within a domain. Routing messages may be used to disseminate the latency of links via a signaling and routing protocol. Advantageously, the present invention provides measurement of latency and latency variation of customer circuits (i.e., SNCs) using an in-band, non-intrusive calculation with a high-degree of accuracy. Furthermore, the present invention may consider these calculations for circuit routing based on the latency and circuit acceptance based on maximum latency restrictions.

Systems and methods for connecting and configuring a communication network are described. A network includes a first router; a tie-line having a plurality of full duplex dedicated router interconnects connected to said first router; a second router connected to said plurality of full duplex dedicated router interconnects; a first user connected to said first router with a first full duplex loop; and a second user connected to said second router with a second full duplex loop. The systems and methods provide advantages in that bursty control information can be multiplexed with time sensitive laminar data.

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 system and method for quantum key delivery in a single-photon, free-space cryptography scheme including a transmitter and a receiver. The transmitter includes two pairs of photon sources, each of which represents a specific photon polarization direction. The first pair of photon sources represents a first polarization basis while the remaining pair of photon sources represents a second polarization basis. The first and second polarization basis are rotated with respect to each other so as to produce non-orthogonal polarization eigenstates. A transmitter polarizing beamsplitter corresponding to each of the pairs of the photon sources is provided whereby the polarizations of each of the photon sources of each pair of photon sources are recombined. A transmitter non-polarizing beamsplitter is provided whereby the recombined polarizations are combined for output to the receiver. The receiver includes a set of optics inversely disposed with respect to the optics of the transmitter and two pairs of photon detectors.

The present invention includes novel techniques, apparatus, and systems for optical WDM communications. Various wavelocker apparatus and methods are disclosed that measure the frequency offsets between signal lasers and reference lasers. The measured offsets are used to adjust the signal laser frequencies to meet their target frequencies. The absolute accuracy of the reference laser frequency is improved by measuring the absorption of the reference laser by a gas cell with known fixed absorption lines versus the reference laser frequency. Apparatus and methods are disclosed to cover scenarios in which the reference laser polarization is aligned with the signal lasers, as well as those in which the reference laser polarization is not aligned with the signal lasers. The wavelocker apparatus may or may not be located at the same network site as the signal lasers.

A point-to-multipoint communications network includes an optical line terminal (OLT) and a number of optical network terminals (ONTS) which each detect and remove rogue ONTs from the network. The OLT monitors transmission errors to detect the presence of a rogue ONT, and can determine the identity of the rogue. Each ONT monitors its own upstream data packets to detect the presence of a rogue, and turns itself off when a rogue is detected.

By using low-frequency signals, an optical transmitting unit modulates one of a wavelength, a transmission timing, and an intensity of light as a carrier wave. A polarization multiplexer synthesizes the output light signals, modulated by the optical transmitting unit, in polarization states orthogonal to each other and generates polarization-multiplexing signals. A polarization splitter splits by extracting two orthogonal polarization components from the polarization-multiplexing signals. The polarization states of the polarization-multiplexing signals are controlled by a polarization controller in an optical receiving unit. A band-pass filter extracts components transmitting through passbands from output signals of the optical receiving unit and outputs an intensity of the components. Based on the intensity output from the filter, a controlling circuit generates feedback control signals for maximizing a ratio of the components of the low-frequency signals and by using the feedback control signals, the polarization controller controls the polarization states of the optical multiplexing signals.

The present invention is directed toward systems for conducting laser range and enabling optical communication between a plurality of entities and to the application of such systems in a secure covert combat identification system. In one embodiment, the present invention uses a novel laser system that generates high pulse rates, as required for optical communications, while concurrently generating sufficiently high power levels, as required by laser range finding operations. One application of the present invention is in enabling secure covert communications between a plurality of parties. Another application of the present invention is in tracking and identifying the movement of objects.