Abstract: A system for monitoring of integrity of a communication bus includes a communication bus cooperating with at least one transmitter configured to generate and transmit a signal on communication bus. At least one receiver is configured to receive a signal generated by the transmitter and transmitted on communication bus. The receiver is further configured to receive the transmitted signal as well as any reflected signals arising from non-impedance matched section in communication bus and wherein a time difference between transmitted pulse width and received pulse width indicates a distance between the non-impedance matched section and the transmitter on the communication bus.

Abstract: In a transmission control apparatus, connected communication devices are detected to find round trip time of transmission to each of the detected communication devices, and the order of each communication device is determined on the basis of the round trip time of transmission to that communication device depending upon the distance thereto. On the basis of the round trip times of transmission to, and the orders of, the communication devices, transmission wait times are determined for delaying transmission of control signals from the communication devices to notify the communication devices of the transmission wait times. When starting communication with the communication devices, timer start signals prompting the communication devices to start counting the transmission wait time are transmitted to the communication devices.

Abstract: Plural optical communication apparatuses are connected through communication lines with a star topology to an optical coupler that is arranged at the center of star topology and can distribute input light. Each optical communication apparatus makes an optically transmitting unit input an optical signal into an optically inputting unit of the optical coupler, and makes an optically receiving unit receive an optical signal output from an optically outputting unit of the optical coupler, for detecting a collision based on the reception signal. After transmitting an optical signal from the optically transmitting unit, each of optical communication apparatuses makes the optically receiving unit receive the optical signal, performs the collision detection based on the comparison between the transmission signal and the reception signal.

Abstract: One embodiment provides a system for performance monitoring in a passive optic network (PON). The system includes an optical line terminal (OLT) and an optical network unit (ONU). The OLT includes an optical transceiver configured to transmit optical signals to and receive optical signals from the ONU, and a performance monitoring mechanism configured to monitor performance of the PON based on received optical signals.

Abstract: An optical switching device includes plural wavelength selective switches that respectively have a first port and a plurality of second ports; and an optical coupler that has a plurality of third ports on an input-side or an output-side, respectively optically coupled to the first ports of the wavelength selective switches.

Abstract: A method and an optical component for data processing in an optical network are provided, wherein two sets of wavelengths are allocated; wherein at least one set of wavelengths is monitored; and wherein a collision between the two sets of wavelengths is avoided or compensated by adjusting at least one laser of an optical component. Furthermore, an optical communication system is suggested including said optical component.

Abstract: A device may include a first module to capture information relating to network traffic passing through a first interface in a network device. A second module may capture information relating to network traffic passing through a second interface in the network device. A control module may be configured to transmit control commands to the first module and the second module, the control commands instructing the first module and the second module to capture information relating to network traffic passing through the first interface and the second interface, respectively. The control module may be further configured to receive the captured information from the first module and the second module, correlate the received information from the first module and the second module; and provide the correlated information to a user.

Abstract: One embodiment provides a system for performance monitoring in a passive optic network (PON). The system includes an optical line terminal (OLT) and an optical network unit (ONU). The OLT includes an optical transceiver configured to transmit optical signals to and receive optical signals from the ONU, and a performance monitoring mechanism configured to monitor performance of the PON based on received optical signals.

Abstract: A method of arbitrating data transmissions to prevent data collisions in an optical data interconnect system including a transmitting node, a plurality of receiving nodes, and one or more remaining nodes connected through an optical data channel. The method involves transmitting a transmission request signal from the transmitting node over an arbitration channel corresponding to the transmitting node, monitoring, at the transmitting node, a plurality of arbitration channels corresponding to each of the plurality of receiving nodes and the one or more remaining nodes at the transmitting node for a predetermined period of time, determining a start time for a data transmission from the transmitting node based on the monitored signals to prevent a data collision, and initiating a data transmission of a data signal from the transmitting node over the optical data channel at the determined start time.

Abstract: Systems and techniques for regulating the security of information flow can include multiple information receiving/transmitting domains where a device failure in one or more domains would not comprise the security of the systems. The systems and techniques may be implemented using a multi-domain checking approach in which the respective device operation status in each receiving/transmitting domain is independently monitored. The systems and techniques can advantageously prevent sensitive information from being inadvertently transferred to an untrusted or unauthorized entity.

Abstract: Plural optical communication apparatuses are connected through communication lines with a star topology to an optical coupler that is arranged at the center of star topology and can distribute input light. Each optical communication apparatus makes an optically transmitting unit input an optical signal into an optically inputting unit of the optical coupler, and makes an optically receiving unit receive an optical signal output from an optically outputting unit of the optical coupler, for detecting a collision based on the reception signal. After transmitting an optical signal from the optically transmitting unit, each of optical communication apparatuses makes the optically receiving unit receive the optical signal, performs the collision detection based on the comparison between the transmission signal and the reception signal.

Abstract: A method of detecting transmission collisions in an optical data interconnect system. The method includes initiating a data transmission of a data signal from a transmitting node over the optical data channel, transmitting a first collision detect signal from the transmitting node throughout a duration of the data transmission where the first collision detect signal is transmitted over an optical detection channel corresponding to the transmitting node, monitoring at the transmitting node of the optical data interconnect system for a predetermined period of time, where the optical data interconnect system further includes optical collision detection channels corresponding to each of a plurality of receiving nodes and one or more remaining nodes, and identifying a transmission collision when a second collision signal is received through one of the optical collision detection channels at the transmitting node during the predetermined period of time.

Abstract: A method is provided including the steps of monitoring at least one performance metric of at least one network component in an optical network system, determining whether the at least one network component is a rogue network component using the at least one performance metric, saving environment data to a non-volatile storage medium, and modifying the operation of the rogue network component to reduce interference of the rogue network component with the optical network system. In another embodiment, a method includes detecting a condition of a network component in an optical network system, and writing environment data of the network component to a non-volatile storage medium.

Abstract: In accordance with the teachings of the present invention, a system and method for managing wavelength drift in an optical network is provided. In a particular embodiment, the method includes receiving traffic in one or more optical channels transmitted by one or more transmitters, each channel having successive timeslots, each transmitter assigned to transmit in a channel in allocated timeslots in the channel. The method also includes determining whether the traffic received in a particular channel in a particular timeslot was transmitted by one of the transmitters that was not assigned to transmit in the particular channel.

Abstract: A device may include a first network module to capture network data at a first location in a network and a second network module to capture network data at a second location in the network different from the first location in the network. The device may include a control module to receive control commands relating to the first network module and the second network module. The control module may forwarded the control commands to the first network module and the second network module. The control module may receive the captured network data from the first network module and the second network module.

Abstract: A laser beam multiplexer capable of easily multiplexing a plurality of laser beams is provided. A laser beam multiplexer includes a multiplexing element having a hollow portion with a sectional elliptical shape, in which the multiplexing element includes: a plurality of light-incident apertures guiding laser beams from outside toward one of two focal points of the hollow portion, a reflective layer arranged on a wall surface of the hollow portion, and multiplexing a plurality of incident laser beams while reflecting the plurality of laser beams, and a light-emitting aperture guiding laser beams multiplexed by the reflective layer toward outside.

Abstract: The Fibre Channel Credit Extender (FCCE) (600) is a network device that is disposed between and connected to an end node (210) and an optical repeater (220). The FCCE (600) contains as many buffer credits as necessary, to solve bandwidth problems in a network. In a situation where maximum bandwidth is required in both directions of a link, the FCCE (600) breaks a single logical link into three physically separated “linklets.” The short-distance linklets attain maximum bandwidth by use of the existing buffer credits of the end nodes. The long-distance linklet attains maximum bandwidth by use of very high receive buffer credits in the FCCEs (600). In this way, only those links that need maximum bandwidth over distances not covered by end-node credit counts need be attached to an FCCE (600). The FCCE (600) contains the optical repeater to gain distance on that link, and contains high credit count receive buffers to gain bandwidth on the link.

Abstract: Methods and systems for using a wavelength as an address in an optical network are disclosed. In particular, methods for selecting a wavelength for a particular node in an optical network, resolving a wavelength for a destination node in an optical network from a network address, and receiving and transmitting data packets at particular wavelengths are disclosed. A resulting system implementing such methods may significantly reduce space, weight and power measurements while transferring data at high rates for a data network.

Abstract: An optical communication system includes an optical ring that couples a hub node and a plurality of local nodes. The hub node is capable of receiving traffic over the optical ring from the plurality of local nodes on a transmitting wavelength and transmitting traffic over the optical ring to the local nodes on a receiving wavelength. At least one local node is capable of adding traffic to the optical ring by determining whether any other local node is transmitting at the transmitting wavelength and, in response to determining that no other local node is transmitting at the transmitting wavelength, transmitting a request message to the hub node requesting use of the transmitting wavelength. The local node adding traffic is further capable of receiving a grant message from the hub node and, in response to receiving the grant message from the hub node, transmitting traffic at the transmitting wavelength.

Abstract: An optical transmission apparatus includes optical transmitters for transmitting optical signals and first monitor units for monitoring optical signals from the optical transmitters. A multiplexer is provided for multiplexing the optical signals from the optical transmitters into a multiplexed signal. A second monitor unit is provided for monitoring each optical signal which is multiplexed in the multiplexed signal from the multiplexer. A processing unit is provided for comparing a first number of optical signals detected by the first monitor units and a second number of optical signals detected by the second monitor unit.

Abstract: A system and method for detecting digital symbols carried in a received optical signal. The system comprises a functional element operative to receive a stream of samples of an electrical signal derived from the received optical signal and to evaluate a non-linear function of each received sample, thereby to produce a stream of processed samples. The system also comprises a detector operative to render decisions about individual symbols present in the received optical signal on the basis of the stream of processed samples. In an embodiment, the non-linear function computes substantially the square root of each received sample.

Abstract: A system and method for communicating between serially connected electrical devices of a network is provided. The network includes a series of electrical devices, and fiber optic connectors between electrical devices of the series of electrical devices forming a closed communication ring in which output of each electrical device is communicatively connected to input of a subsequent electrical device of the series of electrical devices.

Abstract: An Ethernet passive optical network (EPON) ring for providing protection against fiber failures. The optical network unit (ONU) is coupled to the ring fiber by a three-port passive optical splitting module that has three two-way optical passages. By the three two-way optical passages, the OUN receives/transmits data from/to the two ends of the optical line termination (OLT) to provide protection while the fiber failure. Moreover, it provides better authorization of users and simpler collision detection by the two-way transmission of the three-port passive optical splitting module to prevent hackers from invading and to reduce collisions.

Abstract: In an optical transmission apparatus in which a plurality of nodes are optically connected to one another via an optical transmission path, a light signal which is coded so that a mixture ratio of 1 and 0 constituting data is made close to 50% is transmitted through the optical transmission path. When a light signal is not emitted from all of the nodes, a dummy signal which is an AC-like signal is emitted to the optical transmission path. Therefore, an optoelectric conversion section can be always set to an active state, and the signal recognizability can be prevented from being lowered.

Abstract: A method and apparatus for allocating time slots in a communications network, comprising a headend, a plurality of outstations, and a shared medium connecting each outstation to the headend. The method involves scheduling timeslots for each outstation responsive to the measures of distance of each outstation from the headend. The method reduces the requirement for guard bands between timeslots, since it obviates allocation of a guard band between consecutive first and second timeslots where the outstation allocated the second timeslot is located no closer to the headend than the outstation allocated the first time slot. Ideally, the timeslots are allocated to outstations cyclically in ascending order of distance of the outstations from the headend, with the closest outstation following the farthest to complete the cycle, so that guard bands are rendered unnecessary between the majority of timeslots.

Abstract: A method and system for providing priority to a station in a congested half duplex Ethernet network. Specifically, one embodiment of the present invention includes a method for providing priority to a peripheral component (e.g., half duplex Network Interface Card) in a congested network. The method includes the step of detecting a collision of a data packet during transmission of the data packet by a peripheral component coupled to a network. Furthermore, the method includes the step of determining a restricted back off time. It should be appreciated that the restricted back off time is substantially equal to or less than a restricted time value. Additionally, the method includes the step of causing the peripheral component to wait the restricted back off time before trying to retransmit the data packet over the network.

Abstract: A bit rate control apparatus having a delay unit for delaying an input signal received in an optical receiver in an optoelectrically-converted state; a DC level outputting unit for exclusively OR'ing the input signal with the delayed signal outputted from the delay unit; an A/D converting unit for A/D converting a DC level outputted from the DC level outputting unit; a clock/data reproducing unit for reproducing clocks and data based on a bit rate control signal; and a control unit for calculating a variation in the DC level at every interruption timing, which is previously set, based on the A/D converted signal, and for determining whether the DC level variation occurs under the influence of temperature or due to a variation in bit rate based on a difference between the calculated DC level variation from a predetermined variation limit.

Abstract: The present invention provides methods, apparatus and systems for protecting connections between optical cross-connect switches and client equipment. A connection failure is detected, signaled, and a switch made by the client equipment and the optical cross-connect switch to a protection connection between them so as to minimize service interruption. An out-of-band channel or an in-band channel can be used to signal the connection failure.

Abstract: A system (100) to enable the transfer of Internet protocol (IP) format data (12, 14) over a point-to-multipoint passive optical network (PON, 16) is illustrated in FIG. 2. An exchange (102) is connected to a plurality of outstations (104-108) via an optical communication resource (24, 26-38) including a passive optical splitter (22) providing isolation to individual outstations. Media access control of the plurality of outstations is administered by the exchange (102), with collision detection logic (112) in the exchange determining collision (158) of Internet protocol (IP) encoded data communicated thereto through the PON (16). The IP encoded data realises a transport mechanism through the PON. Each of the plurality of outstations (104-108) and the exchange (102) is adapted to pass data in an IP format to and from the optical communication resource such that IP encoded data is transported, in use, directly between the outstation and the exchange.