6206results 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 signal router is described. The signal router includes a switching matrix, an error detector and a controller. The switching matrix includes a first number of inputs and a second number of outputs, and is configured to receive an information stream. The error detector is coupled to one of the second number of outputs, and is configured to generate error information by virtue of being configured to detect errors in the information stream. Likewise, the controller is coupled to the switching matrix and error detector. The controller is configured to select one of the first number of inputs, receive error information from the error detector, and configure the switching matrix to couple the selected input to one of the outputs.

A method for testing a fiber drop terminal from a single geographic location may include placing a signal onto a first optical fiber at the single geographic location. The first optical fiber is communicatively coupled to a first output receptacle on the fiber drop terminal. The method may also include detecting the signal via a second optical fiber at the single geographic location. The second optical fiber is communicatively coupled to a second output receptacle on the fiber drop terminal, and the second output receptacle is communicatively coupled to the first output receptacle via a loop-back assembly.

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.

An optical signaling header technique applicable to optical networks wherein packet routing information is embedded in the same channel or wavelength as the data payload so that both the header and data payload propagate through network elements with the same path and the associated delays. The technique effects survivability and security of the optical networks by encompassing conventional electronic security with an optical security layer by generating replicated versions of the input data payload at the input node, and the transmission of each of the replicated versions over a corresponding one of the plurality of links. Moreover, each of the links is composed of multiple wavelengths to propagate optical signals or optical packets, and each of the replicated versions of the data payload may be propagated over a selected one of the wavelengths in each corresponding one of the plurality of links.

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.

A cable modem termination system is disclosed with flexible mapping of upstreams to downstreams and flexible mapping of downstreams to optical nodes and optical nodes to upstream receivers and the ability to add singe upstreams or downstreams as needed for load balancing. Multiple downstreams can share the same upstream. Multiple receivers can be coupled to the same upstream. Monitoring of upstream performance for overperforming or underperforming modems can be carried out, and new upstreams with higher and / or lower throughtput can be created to service the overperformers and / or underperformers. Modems can be grouped into logical groups with different performance levels and serviced by different upstreams or different upstream logical channels on the same upstream physical channel. An upstream linecard with a digital crosspoint switch is disclosed with the switch operated during contention intervals to allow reception with or without aggregation of noise where multiple upstream share the same receiver.

A WDM add / drop device for use in an optic communications system for adding and dropping optical wavelengths from a multiple-wavelength optical system. The device includes a set of lenses, a planar grating wavelength multiplexer and a micromirror array switchable for individual wavelengths of the multiple-wavelength signal between a transmit mode and a reflect mode. The grating angularly demultiplexes a multiple-wavelength optical signal in a first direction and the individual wavelengths are processed by the micromirror array and directed to the grating in a second direction. The micromirror array will either reflect select wavelengths to a first port or transmit select wavelengths to a second port. In a preferred embodiment, ports on a first multiport circulator input the multiple-wavelength optical signal to the WDM add / drop device and output the multiple-wavelength optical signal from the WDM add / drop device. A second multiport circulator provides to-be-added wavelengths to the WDM add / drop device and removes to-be-dropped wavelengths from the WDM add / drop device.

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.

Component malfunctions in passive optical networks (PON) can increase bit error rates and decrease signal-to-noise ratio of communications signals. These faults may cause the receivers of the signals, either the optical line terminal (OLT) or optical network terminals (ONTs), to experience intermittent faults and / or may result in misinterpreted commands that disrupt other ONT's communication, resulting in a rogue ONT condition. Existing PON protocol detection methods may not detect these types of malfunctions. An embodiment of the present invention identifies faults in a PON by transmitting a test series of data patterns via an optical communications path from a first optical network node to a second optical network node. The test series is compared to an expected series of data patterns. An error rate may be calculated as a function of the differences between the test series and expected series. The error rate may be reported to identify faults in the PON. Through use of the embodiment, network faults can be identified and optionally automatically corrected, saving a network service provider from expending technician time and maintaining an operating state of the network.

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 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 signal transmission system includes an interface unit that monitors the operating condition of each device. The signal transmission system also includes a simulator that simulates the transmission quality of the system in response to the operating condition of each device, and controls each device so as to optimize the transmission quality.

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.

Circuitry for monitoring operation of an optoelectronic device having a laser transmitter and a photodiode receiver includes analog to digital conversion circuitry for receiving a plurality of analog signals from the laser transmitter and photodiode receiver, converting the received analog signals into digital values, and storing the digital values in predefined memory-mapped locations within the optoelectronic device. Comparison logic compares one or more of these digital values with limit values, generates flag values based on the comparisons, and stores the flag values in predefined locations within the optoelectronic device. An interface enables a host device to read from and write to host-specified memory mapped locations within the optoelectronic device.

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.