Abstract: A wavelength division multiplexing-passive optical network (WDM-PON) system includes a light source provider configured to wavelength-division-multiplex a laser light source of a wavelength allotted to each subscriber and optical-power-divide the multiplexed light source, a plurality of optical line terminals each configured to transmit a light source for upward signal with the power-divided light source and convert an upward optical signal into an electric signal, a plurality of optical network units each configured to convert the light source for upward signal into the upward optical signal, and a multiplexer/demultiplexer configured to separate the signal source for upward signal transmitted from the optical line termination in each subscriber or to multiplex the upward optical signal for each subscriber transmitted from the optical network unit so as to transmit the multiplexed signal into the optical line terminal.

Abstract: The present disclosure provides a method for the master to configure the slaves for use in a passive optical network (PON) system, comprising: the slaves generating a managed entity (ME) Support List ME based on their individual hardware configuration; the master obtaining the ME Support List ME; and the master configuring the slaves based on this list. The technical solution of the present disclosure allows speeding up of the optical network terminal (ONT) service clearance time by quickly identifying incompatibility of the optical line terminal (OLT) with the ONTs.

Abstract: In a method of allocating a bandwidth of a passive optical network, downward data are transmitted by varying a wavelength based on a wavelength division method and upward data are transmitted using a time division method. Thereby, by efficiently allocating a network bandwidth, data can be transmitted and by realizing statistical multiplexing, transmission efficiency can be improved.

Abstract: System and method for data synchronization in Passive Optical Networks. According to an embodiment, the present invention provides a method for providing upstream data synchronization in an optical communication network. The method includes sending data from an Optical Network Unit. The data includes a first data frame, which includes a header sequence, a synchronization segment, and a data segment. The synchronization segment includes 66 bits, which includes a first number of bits having nonzero values and a second number of bits having a value of zero. The first number is different from the second number. The method further includes receiving at least the first data frame by an Optical Line Terminal. The method also includes processing the first data frame. The method additionally includes selecting a first segment of the first data frame, the first segment including 66 bits.

Abstract: An Ethernet-based optical network system includes a first optical transmitter that can receive a first electric signal and to produce a first optical signal, a first optical receiver that can convert the first optical signal to a second electric signal. The first electric signal, the first optical signal, and the second electric signal have a first transmission baud rate. A down converter can receive a third electric signal having the first transmission baud rate and to produce a fourth electric signal having a second transmission baud rate. A second optical transmitter can receive the fourth electric signal and produce a second optical signal having the second transmission baud rate. A second optical receiver can convert the second optical signal to a fifth electric signal having the second transmission baud rate. An up converter can convert the fifth electric signal to a sixth electric signal having the first transmission baud rate.

Abstract: An optical subscriber network system is disclosed, which comprises: a server bi-directional optical transmitter including a multiplexer to multiplexes communication data and broadcast data, a server laser diode to converts the multiplexed data into an optical signal, and a server photo diode receive communication data from a subscriber, wherein the server bi-directional optical transmitter transmits the upstream communication data; and a subscriber bi-directional optical receiver including a subscriber laser diode to transmit upstream communication data, a subscriber photo diode to receive the optical signal transmitted from the server bi-directional optical transmitter, and a demultiplexer to demultiplex and divide the multiplexed signal into communication data and broadcast data. In the optical subscriber network system, the optical transmitter and the optical receiver can transceive image signals and Ethernet communication signals in a two-way direction by means of a single laser diode and photo diode.

Abstract: Disclosed is a passive optical network comprising a central office including a plurality of first reflective semiconductor optical amplifiers of a quantum-dot type, each of which generates a wavelength-seeded downstream optical signal on a downstream channel of a corresponding wavelength, a plurality of optical network units each of which includes a second reflective semiconductor optical amplifier of a multi-quantum-well type, the second reflective semiconductor optical amplifier generating a wavelength-seeded upstream optical signal on an upstream channel of a corresponding wavelength and a remote node for outputting the downstream optical signals to corresponding optical network units, and multiplexing and outputting the upstream optical signals to the central office.

Abstract: A method of managing forward error correction (FEC) initialization and auto-negotiation in ethernet passive optical networks includes receiving FEC data from an optical network unit (ONU 105), and the optical line terminal (OLT 103) responds to the ONU with FEC data. Upon receiving data not forward error corrected from an ONU. The OLT responds with data not coded for FEC (203). Similarly, upon receiving forward error corrected data from the OLT, the ONU responds with forward error corrected data (503); and upon receiving data not forward error corrected from the OLT, the ONU responds with data not forward error corrected (203). The communications quality from the ONU is monitored (501), if the communications quality is not sufficient, the OLT transmits forward error corrected data to the ONU; otherwise, the OLT transmits non-FEC data to the ONU.

Abstract: In one embodiment, the present invention includes a network hub having an active optical encoder where the network hub is to generate a plurality of addressed optical data signals, each having a common carrier wavelength and a different address corresponding to a network node coupled to the network hub. Other embodiments are described and claimed.

Abstract: A network may include fiber optic lines and fiber distribution panels connected by the one or more fiber optic lines. At least one of the fiber distribution panels may include an optical fiber connector designated as a connector that is for emergency use. The network may further include a plurality of optical network terminals located at premises of subscribers to the network.

Abstract: In a passive optical network system, upon detecting a connection with one of a plurality of optical network units at the time of performing autonomous ranging, an optical line termination requests for subscriber recognition information from the connected optical network unit, searches a database, to thereby specify the subscriber and the service details, and performs bandwidth setting and connection setting based on specified service details. The optical network unit stores the subscriber recognition information input by a subscriber, in association with the subscriber information.

Abstract: The present invention provides a solar-pumped active device which utilizes a holographic antenna grating on a solar energy silicon substrate to select specific diffracted wavelength and couple pump wavelength in an approximately vertical way and converge the pump wavelength to excite an optical gain medium so that an optical amplifier or a laser can be obtained. The present invention requires no big size and is flexible over the surface shape and is suitable for free space optical communications on the ground and satellite optical communications. It means that the holographic antenna grating can be applied on the top floor of a building or on the glass surface of an outer wall. If it is applied to a satellite, the present invention can be deposited on a solar energy cell substrate to form a high optical amplification so that not only the electricity required in satellite optical communications can be reduced, but also a high-speed and large capacity of data can be transferred between satellites.

Abstract: The invention relates to an EPON bridge apparatus and a forwarding method thereof. In case of receiving frame from the network port or the PON port, the apparatus associates the port having the received frame inputted with source MAC address of the received frame to learn the information in an FDB table which manages port information for the learned MAC address. Then the apparatus refers to the FDB table to remove LLID from upstream frame, and then forwards the upstream frame to the network port, while attaching LLID corresponding to destination MAC address to downstream frame to transmit to the PON port. Bridging between ONUs are possible with flooding capability using anti-LLID. It provides VLAN-LLID translation mode with support for VLAN tag addition/removal at the ONU side. It also provides multicast pruning function for the downstream.

Abstract: An optical network remote power supply system is proposed, which is designed for use with an optical network for supplying power to a remote switching unit, and which is characterized by the provision of a light source on the local site which can transmit a light beam via the optical transmission line to the remote site, where the light beam is converted into electricity for storage in an electrical energy storage module, such as a rechargeable battery unit or a capacitor. This feature allows the remote switching unit to be powered by the electricity stored in the electrical energy storage module in the event of a failure to the primary channel when the remote switching unit is responsible for switching to the secondary channel.

Abstract: Provided is a communication apparatus in a PON bridge sublayer, which supports point-to-point communications between optical network units (ONU) in an Ethernet passive optical network (EPON). To support point-to-point communications between ONUs in the EPON, the communication apparatus in the PON bridge sublayer includes a second processing portion, a second input queue, a second lookup and learning portion, a second output queue, a first input queue, a first lookup and learning portion, a filtering database table a VLAN ID table, a table control portion, a first output queue, and a first processing portion.

Abstract: A communication node system for an Ethernet-PON includes: an LLID register for storing an LLID being an allocated identifier; a preamble generator for generating a PON preamble; a CRC generator for generating a CRC for the preamble; a transmission connector for combining transport data with the CRC-including preamble to generate a transport frame, and forwarding the transport frame; a reception connector for receiving the frame and dividing the frame into a preamble and received data; a filter for extracting an LLID from the preamble, comparing the extracted LLID with the LLID stored in the register, and selectively filtering the extracted LLID; and a received frame generator for discarding the received data, or combining the received data with the preamble to generate a received frame.

Abstract: A self-healing passive optical network is disclosed. The network includes a central office and a remote node connected to the central office through a main optical fiber. The remote node transmits one portion of power of the upstream optical signal, which has been input from each of the optical network units, to the central office, and returning a remaining portion of the power of the upstream optical signal to the optical network unit. The network also includes a plurality of optical network units connected to the remote node through a plurality of distribution optical fibers. Each of the optical network units transmits an upstream optical signal to the remote node through the directly connected distribution optical fiber, and detects abnormality occurrences from a state of the upstream optical signal returning from the remote node.

Abstract: Disclosed is a point-to-point emulation method for operating an Ethernet passive optical network having an optical line terminal (OLT) and a plurality of optical network units (ONUs) each connected to the OLT. A tag Ethernet frame transmitted between the OLT and the ONUs includes a destination address (DA) field representing a destination address, a source address (SA) field representing a source address, and an LLID field in which a unique LLID assigned to an object of the ONU side is recorded. The LLIDs are assigned to ports of a bridge or an L2 (Layer 2) switch of the OLT side on a one-to-one basis. The OLT, upon receiving a tag Ethernet frame, outputs an LLID field-deleted Ethernet frame to the bridge or L2 switch port to which an LLID in the received frame is assigned. The bridge or the L2 switch transmits the Ethernet frame to a port to which a previously learned destination address is assigned.

Abstract: In a system and method of optical communication, optical signals are generated in multiple wavelength channels. Each optical signal is passively transported from an origination node of a network to a destination node. The destination node is determined by the signal wavelength. For at least some signals, the passive transport includes transport through a branch point of the network, such that the signal wavelength determines the output branch through which the signal is routed. In certain embodiments, signals are generated according to a schedule devised to substantially prevent the concurrent arrival, at the same destination node, of signals having the same wavelength but coming from different origination nodes.

Abstract: A passive optical network. The optical network has an optical fiber ring with ends terminating at an optical line terminal. The optical line terminal transmits signals through the fiber ring to optical network units passively connected to the fiber ring. The optical network units receive signals from the optical line terminal through the fiber ring. In one embodiment, the optical line terminal transmits redundant signals in opposite directions through the fiber ring and the optical network units receive the redundant signals from opposite directions through the fiber ring. In another embodiment, the optical network units receive TDM signals from and transmit TDMA signals to the optical line terminal through a fiber line. A first WDM coupler passively connected to the fiber line multiplexes an overlay signal with at least one of the TDM signals and the TDMA signals for transmission through the fiber line. The overlay signal has a wavelength different than the signals with which it is multiplexed.

Abstract: Disclosed is a wavelength division multiplexing passive optical network (WDM PON) system in which an optical signal outputted from a central office is injected into a Fabry-Perot laser diode (F-P LD) as the light source of an optical network unit, so that the output wavelength of the optical network unit is injection-locked at the same wavelength as that of the optical signal outputted from the central office, thereby enabling the optical network unit to output an optical signal having the same wavelength as that of the optical signal outputted from the central office. In accordance with this system, it is possible to transmit and receive forward and backward data at the same wavelength by the unit of channels. Since inexpensive F-P LDs are used as respective light sources of the central office and optical network units, it is possible to efficiently and economically implement a WDM PON system.

Abstract: An optical communications system includes a receiver subsystem with at least two heterodyne receivers. The receiver subsystem receives a composite optical signal having two or more subbands of information and corresponding tones. An optical splitter splits the composite optical signal into optical signals. Each optical signal includes a subband(s) and corresponding tone. Each heterodyne receiver receives an optical signal. The receiver includes a heterodyne detector coupled to a signal extractor. The heterodyne detector mixes the optical signal with an optical local oscillator to produce an electrical signal which includes a frequency down-shifted version of the subband and the tone of the optical signal. The signal extractor mixes the frequency down-shifted subband with the frequency down-shifted tone to produce a frequency component containing the information.

Abstract: A passive optical network employs wavelength-dependent routing, and terminals that transmit request packets (requesting a data transmission slot) in a common signalling time slot. Different delays are then applied to packets on different wavelength channels, allowing a number of request packets to be processed in sequence by a single optical receiver at the network controller.

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: 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.

Abstract: In a video signal transmission system and method, a video signal and a pre-defined synchronization signal, generated according to the logic status of first control signals, are converted into first DC-balanced data and second DC-balanced data, respectively. The first data and second data are converted into a first serial data stream and a second serial data stream, respectively, and the data streams are transmitted over a first channel. Third data and fourth data are detected by correcting skew of the first serial data stream and the second serial data stream received through the first channel. The first data is encoded and transmitted so that the second data and the third data are not the same. The first serial data stream is transmitted over the first channel in response to an activated second control signal, while the second serial data stream is transmitted over the first channel in response to a deactivated second control signal.

Abstract: A method of setting up two-way optical communication between a central unit and a remote unit suitable for operating in a given communication mode selected from a plurality of communication modes. A plurality of frame patterns is defined in the central unit, with each frame pattern being appropriate to one of the communication modes. The plurality of frame patterns are sent sequentially until a coherent response is obtained from the remote unit, the communication mode of the remote unit being the mode which corresponds to the frame pattern which gave rise to the coherent response.

Abstract: A multi-channel optical communication system includes an optical transmitting apparatus and an optical receiving apparatus. The optical transmitting apparatus has a retroreflector and a modulator for modulating light reflected by the retroreflector according to a transmission signal. The light receiving apparatus has a light source and a demodulating circuit for demodulating the transmission signal modulated by the modulator from the light emitted from the light source and reflected from the retroreflector. The modulator includes a plurality of optical reflection devices arranged on a reflection plane of the retroreflector and capable of controlling optical reflection independently of each other and a circuit for separately controlling each of the optical reflection devices. The demodulating circuit includes a CCD having a plurality of photoreceptors arranged correspondingly to the arrangement of the optical reflection devices.

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: The present invention provides a method and network for communicating over free space links. The network includes a plurality of buildings, each housing at least one of a residence and a business. Pluralities of free-space optical links are established, where each optical link is defined between two of the buildings, and data is communicated across the plurality of links. Each of the buildings includes a distribution system configured to receive the data communicated across at least one of the links and to distribute the data to an intended recipient. The plurality of optical links are configured to form a network topology providing alternate communication paths for at least two of the plurality of buildings and an external network is coupled with the optical communication network, wherein at least some of the data is communicated between the external network and the optical communication network.

Abstract: A fiber optic system for communicating between a central office and a downstream station is described. The central office has a TX unit, an RX unit and a continuous wave (“CW”) laser. Each station has an RX unit and a tunable filter coupling the RX unit to the central office. During downstream transmission, the station's tunable filter is tuned to the central office TX wavelength so that the signal transmitted by the central office will pass through the filter and be received by the station's RX unit. During upstream transmission, the station's tunable filter is selectively tuned to a wavelength different than the CW laser wavelength, allowing selective reflection of light from the CW laser back to the central office. The tunable filter can thus be used to modulate the reflected light to effectively create an upstream transmission from the downstream station to the central office.

Abstract: Communications apparatus, including client interface units (CIUs) coupled to network service lines for sending and receiving data carried by the service lines in accordance with respective communication protocols. The CIUs include at least first and second CIUs that communicate with respective first and second channels of the data operating in accordance with different, respective first and second protocols. The apparatus includes optical interface units (OIUs), coupled to a passive optical network (PON) and modulating optical radiation responsive to the data so as to convey the data over the PON. The apparatus further includes a connectivity unit which conveys the data between the CIUs and the OIUs, while mapping the channels to the OIUs so that data from the first and second channels is carried in alternation by one of the OIUs to first and second users of the PON communicating respectively according to the first and second protocols.

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). The present invention enables fast protection switching from the working OSU to the protection OSU. In one embodiment, the arrival times of corresponding upstream ranging reply PLOAM cells are measured at both the working and protection OSUs during ranging operations of the working OSU. In another embodiment, a cell delineation procedure is initiated at the protection OSU during normal, non-ranging operations of the working OSU to enable the protection OSU to correctly delineate upstream cells and the arrival times of corresponding upstream cells are then measured at both the working and protection OSUs.

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: An optical auxiliary signal, produced in a central device, is transmitted in addition to a user signal from the central to a remote optical device via at least two optical supply line fibers which are provided for transmitting optical signals between the central and remote optical devices. The optical auxiliary signal received in the remote optical device is diverted, is transmitted via a second optical supply line fiber to the central optical device, and the reception or the absence of the optical auxiliary signal and of the optical user signal in the central optical device are evaluated in order to monitor the operational state of the optical supply line fibers.

Abstract: A GTC frame Structure and a method for transmission of ONT management control information in GPON. The method comprises the steps of: constructing a GTC frame which includes a PCBd portion having an OMCC field including either destination identifier information for supporting a GEM mode or destination identifier information for supporting a ATM mode, and a payload portion including data; and transmitting the GTC frame. The GTC frame structure for ONT management control information transmission can transmit the management control information to an ONT supporting either ATM mode or GEM mode.

Abstract: Communications apparatus, including client interface units (CIUs) coupled to network service lines for sending and receiving data carried by the service lines in accordance with respective communication protocols. The CIUs include at least first and second CIUs that communicate with respective first and second channels of the data operating in accordance with different, respective first and second protocols. The apparatus includes optical interface units (OIUs), coupled to a passive optical network (PON) and modulating optical radiation responsive to the data so as to convey the data over the PON.

Abstract: The invention provides an automatic bandwidth adjustment method and system in a passive optical network (PON) comprising an optical line terminal (OLT) connected to a plurality of optical network units (ONUs). A particular embodiment of the method according to the invention comprises the steps of transmitting data between at least one of the ONUs and the OLT, detecting if there is any undelivered data in the data being transmitted, queuing the undelivered data in an undelivered data block (UDB) in an upstream frame of the ONU, informing the OLT of the undelivered data using the undelivered data block (UDB), reading the UDB, adjusting bandwidth of the ONU according to the UDB, informing the ONU whether the PON is busy using an unused bandwidth block (UBW), and rejecting a new transmission request between the ONU and the OLT if the PON is busy or unavailable.

Abstract: Mechanisms for providing a subscriber-side interface with a passive optical network are described herein. An optical network termination (ONT) having an integrated broadband passive optical network processor is utilized to receive downstream data from an optical line termination (OLT) via a passive optical network and provide the contents of the downstream data to one or more subscriber devices via one or more data interfaces. Similarly, the ONT is adapted to receive and transmit upstream data from the one or more subscriber devices to the OLT via the passive optical network. The ONT preferably implements one or burst buffers for buffering upstream and/or downstream data. The ONT can be adapted to notify the OLT of the status of the burst buffer, thereby allowing the OLT to modify the bandwidth allocations.

Abstract: A passive optical network includes a central office and a subscriber-side apparatus connected with the central office through an optical fiber link. The subscriber-side apparatus performs communication with the central office based on wavelength-division-multiplexed optical signals. The central office has a routing section, provided with first to fourth multiplexing ports, for demultiplexing multi-wavelength light inputted from the fourth multiplexing port into a plurality of channels. Each of the demultiplexed channels is amplified and multiplexed for output through the first multiplexing port. Optical signals inputted through the third multiplexing port are demultiplexed and outputted upstream. The routing section also multiplexes channels for downstream optical signals, outputting the multiplexed channels through the second port. A splitting section, provided with first to third splitting ports and arranged on a loop optical waveguide connects the first and fourth multiplexing port with each other.

Abstract: A bidirectional optical link for communication between a first data unit and a second data unit using a single optical source. In a broad aspect it includes a modulator/optical receiver system that includes a splitter element; a receiver element and a return modulator. The splitter element receives an incoming modulated optical signal from an optical source associated with a first data unit. It splits the incoming optical signal into a received optical portion and an outgoing optical portion. The receiver element detects the received optical portion and converts the received optical portion to an electrical signal to be communicated to a second data unit. The return modulator element modulates the outgoing optical portion and transmits the modulated outgoing optical portion to the first data unit. The modulation of the outgoing optical portion allows the use of a single, shared optical source.

Abstract: The invention concerns a method of establishing and/or maintaining a wake mode in an electrical installation, which in addition to at least one receiving device has at least one transmitting device that is connected through an optical bus system. So as not to always have to operate the different devices in the stand-by mode when no data traffic takes place through the optical bus system, the state of the art proposes activating the receiving device only part of the time. If during that time the receiving device receives a corresponding signal from the transmitting device, the stand-by mode is ended in order to establish the data exchange. However this operating mode is also disadvantageous because of the power consumption.

Abstract: A GE-PON (Gigabit Ethernet Passive Optical Network) apparatus includes a 2×N splitter, an OLT (Optical Line Terminal) connected to the 2×N splitter via a first path line or a second path line, and a switching unit for switching the first path line or the second path line upon receiving a predetermined control signal. An ONU (Optical Network Unit) generates a switching request according to a signal environment and transmits the generated switching request to the OLT.

Abstract: A communications network includes optical network terminations (ONTs) and an optical line termination (OLT) connected to a passive optical network (PON). The OLT measures round trip transmission delay expressed in time slot duration for each of the ONTs, and orders the ONTs in ascending order of respective delay modulo time slot duration. A desired reception time at the OLT is scheduled for each of the OLTs according to the ascending order and each ONT is commanded to transmit at a command time that leads the respective desired reception time by a respective delay integral time slot duration. The scheduling includes leaving a reception interval spare after the last ONT in ascending order. The ascending delay modulo slot protocol becomes more efficient as the number of time slots per frame increases. If the number of time slots per frame is N, then the efficiency of the protocol is (N−1)/N. Unassigned time required per transmission frame is thereby reduced.

Abstract: There is disclosed a network architecture comprising a first set of N serially connected power splitting centers connected at one end to receive a power signal and at another end to a termination point, each splitting center having an output associated with a sub-network for delivering a portion of the power signal to that sub-network, wherein the power splitting factor in each power splitting center is variable such that the portion of the power signal delivered to each sub-network is variable. The invention is described with particular relation to a double fiber ring optical network.

Abstract: An identification friend or foe system for use by a weapon to determine whether a target that has been selected is a friendly target comprises a signal source attached to the target and arranged to radiate encrypted signals. A detection system attached to the weapon includes a receiver arranged to receive the encrypted signals when the weapon is within a predetermined range from the target. Signal processing apparatus is connected to the receiver and arranged to determine whether the encrypted signals identify the target as being friendly. The central processing unit is arranged to decrypt the encrypted signal and produce a disarm signal if the target is identified as being friendly. The central processing unit preferably is also arranged to produce a signal that causes the weapon to perform a collision avoidance maneuver to avoid colliding with the target if the target is identified as being friendly.

Abstract: A method for identifying faults in a branched optical network having a central office optically connected to a plurality of optical network units by a plurality of optical paths. The method involves transmitting an optical signal from the central office to the optical network units reflecting a portion of the transmitted optical signal back to the central office. This reflected signal is then used to determine whether a fault exists in the branched optical network.

Abstract: In an optical receiver having a pre-amplifier for converting a current signal outputted from an optical detector to a voltage signal, a signal level detecting device is provided to provide an LOS (loss of signal) signal and a reset signal from the output of the pre-amplifier. The signal level detecting device comprising: a capacitor for receiving the output from the pre-amplifier; first and second transistors each consisting of an emitter and a collector connected to the output of the pre-amplifier and a base connected to the collector; a third transistor having a collector connected to the collector of the first transistor and an emitter connected to the collector of the second transistor; and, a common emitter circuit with a pair of resistors connected, respectively, to the emitter and collector of the third transistor and capable of detecting the level of a signal inputted from the collector of the third transistor.

Abstract: The present invention aims at providing an ascending transmission speed controlling method and a communication system in an ATM-PON (asynchronous transfer mode-passive optical network), in which ascending transmission speeds on the PON are dynamically allocated corresponding to actual transmission states of communication channels of a best effort type, to thereby effectively utilize respective bands.

Abstract: Disclosed is a point-to-point emulation method for operating an Ethernet passive optical network having an optical line terminal (OLT) and a plurality of optical network units (ONUs) each connected to the OLT. A tag Ethernet frame transmitted between the OLT and the ONUs includes a destination address (DA) field representing a destination address, a source address (SA) field representing a source address, and an LLID field in which a unique LLID assigned to an object of the ONU side is recorded. The LLIDs are assigned to ports of a bridge or an L2 (Layer 2) switch of the OLT side on a one-to-one basis. The OLT, upon receiving a tag Ethernet frame, outputs an LLID field-deleted Ethernet frame to the bridge or L2 switch port to which an LLID in the received frame is assigned. The bridge or the L2 switch transmits the Ethernet frame to a port to which a previously learned destination address is assigned.