Abstract: A technique for providing an optical signal to a destination. In one embodiment, the technique is realized through the use of an environmentally hardened, modular switch and a fiber distribution methodology. The modular switch may include fiber access ports, power access ports, dual power supply modules, dual switch fabric modules, dual optical trunking modules, and multiple subscriber service modules that house subscriber service ports and serve a total of up to 96 end points. The dual optical trunking modules may act as an interface between an optical network and the dual switch fabrics, and provide redundancy and variable optical transmission distance between the modular switch and the optical network to which the modular switch is connected. The dual switch fabrics are used for switching and aggregating signals and providing redundancy. Each subscriber service module acts as an interface between one or more subscriber end points and the dual switch fabrics of the modular switch.

Abstract: Disclosed is a dense wavelength division multiplexing-passive optical network (DWDM-PON) system utilizing self-injection locking of Fabry-Perot laser diodes, in which output optical signals of different wavelengths are partially fed back by a partial mirror, so as to injection-lock the Fabry-Perot laser diodes, respectively. In accordance with this system, inexpensive Fabry-Perot laser diodes can be used as respective light sources of a central office and optical network units (ONUs). Accordingly, it is possible to minimize the system construction costs, as compared to conventional optical networks.

Abstract: Cost-reduction in an optical communication unit is achieved by using spectrum-sliced modulated broadband light for transmitting upstream signals, instead of using laser light. An optical communication system includes at least one pair of optical communication units that each has a bi-directional network interface in which physical bit rates of transmission signals and reception signals are identical, an optical transmitter, and an optical receiver, and that performs bi-directional transmissions via at least one optical fiber. One optical communication unit includes a physical bit rate down-converter that lowers the physical bit rate of transmission signals from the bi-directional network interface and outputs to the optical transmitter, and the other optical communication unit includes a physical bit rate up-converter that raises the physical bit rate of signals received by the optical receiver and outputs to the bi-directional network interface.

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: An optical extending device for use in transmission of optical signals which comprise at least one sequence of periodic optical signals, said optical device comprising: a first fiber optic having a characteristic dimensional propagation coefficient equal to ?1 and adapted to be connected to a single mode second fiber optic having a length equal to L0 and a characteristic dimensional propagation coefficient equal to ?0, wherein Lp, the length of said first fiber optic is substantially equal to {[T2/??L0*?0]/?1}*{1?MOD(L0/{T2/??L0*?0]/g(b)}} and wherein: n is an integer 1, 2, 3 . . . and is selected in accordance L0, the length of the single mode second fiber optic; T is a time period of the periodic optical signals; and MOD is the remainder obtained from dividing 10 by {[T2/??L0*?0]/?1}.

Abstract: The optical fiber-based communication system comprises a distribution optical fiber that extends proximately to a plurality of end users, and tap-off modules coupled to the distribution optical fiber at intervals along its length. Each of the tap-off modules includes a port in optical communication with the distribution optical fiber. The optical fiber-based communication system additionally comprises a branch optical fiber connected to the port of each of at least some of the tap-off modules and that extends to a corresponding one of the end users.

Abstract: An all optical network for optical signal traffic has at least a first ring with at least one transmitter and one receiver. The first ring includes a plurality of network nodes. At least a first add/drop broadband coupler is coupled to the first ring. The broadband coupler includes an add port and a drop port to add and drop wavelengths to and or from the first ring, a pass-through direction and an add/drop direction. The first add/drop broadband coupler is configured to minimize a pass-through loss in the first ring and is positioned on the first ring.

Abstract: An optical architecture is provided comprising a plurality of mod/mux units, a master optical distribution hub, a plurality of additional optical distribution hubs, and a plurality of premise stations. Each of the mod/mux units is configured to (i) permit selective modulation of demultiplexed components of a target wavelength band of an optical signal, (ii) multiplex the selectively modulated optical signal, and (iii) direct the multiplexed signal to the master optical distribution hub. The master optical distribution hub is configured to distribute multiplexed signals from respective ones of the mod/mux units to corresponding ones of the plurality of additional optical distribution hubs. Each of the plurality of additional optical distribution hubs comprises an arrayed waveguide grating configured to demultiplex the multiplexed optical signal and distribute respective distinct wavelength portions of the target wavelength band to respective ones of the premise stations.

Abstract: A system and method for configuring lightpaths within an optical circuit wherein the source node stores requests for a lightpath between the source node and the destination node. Upon receipt of a token at the source node indicating an available space within a wavelength, the source node selects a request stored within the queue based upon a best fit window protocol. A lightpath is then established between the source node and the destination node responsive to a selected request.

Abstract: Disclosed herein is a bidirectional wavelength division multiplexed self-healing ring network. The ring network includes a central office and a plurality of remote nodes. Two optical fibers each connect the central office and the remote nodes in a ring form to allow optical signals to be bidirectionally received and transmitted between the central office and the remote nodes. One of the two optical fibers is a drop fiber for transmitting optical signals from the central office to the remote nodes, while the other is an add fiber for transmitting optical signals from the remote nodes to the central office.

Abstract: A system and method for simultaneous delivery of a plurality of independent blocks of 500 MHz digital broadcast television services, stacking a plurality of RF blocks on a plurality of spectrally sliced WDM optical bands.

Abstract: This invention provides a new architecture for a communication system between head-ends and end-users which expands bandwidth and reliability of the communication system. A mux-node receives communication signals from a head-end and forwards the received communication signals to one or more mini-fiber nodes. The connection to the head-end is via a small number of optical fibers and the connections to each of the mini-fiber nodes may be via one or more optical fibers that may provide full duplex communication. The head-end may communicate with the mux-node using digital or digital and analog signals. The mini-fiber nodes may combine the signals received from the head-end with loop-back signals used for local media access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and transmitted to the mux-node.

Abstract: Optical communication systems include a central station that encodes data transmitted to multiplexing (mux) stations or user stations. The central station also decodes data received from the mux stations or user stations. Encoding and decoding are performed using codes, such as composite codes, that designate sources and destinations for data. The mux stations, user stations, and the central station have address encoders and decoders that use, for example, fiber Bragg gratings to encode or decode optical signals according to a code such as a composite code derived by combining codes from one or more sets of codes. A passive optical network comprises one or more levels of mux stations that use such address decoders and encoders to receive, decode, and encode data for transmission toward a central station or a user station.

Abstract: A reconfigurable node for a hybrid fiber cable network includes fiber slots housing a transmitter or receiver interfacing to a head end, coax slots housing an RF brick interfacing with subscribers and RF plug-in modules providing connectivity between the fiber and coax slots. The plug-in modules include connection points, for connection to a fiber or coax slot. A fiber impedance element, associated with the transmitter or receiver in that fiber slot, is connected to each fiber slot. Each fiber impedance element has a different impedance value. A coax impedance element, associated with the RF brick in that coax slot, is connected to each coax slot. Each coax impedance element has a different impedance value. An impedance sensing circuit detects a DC level associated with each connection point which corresponds with the impedance element in a respective fiber or coax slot to determine the location of transmitters, receivers or RF bricks.

Abstract: A method and a system in which selected wavelengths of a wavelength division multiplexed (WDM) signal are modulated with multicast data for multicasting data services on an optical network. The WDM signal is received from a hub node of the optical network, such as a unidirectional ring network or a bi-directional ring network. A four-port wavelength crossbar switch (4WCS) selectably switches selected wavelengths from the optical network to a modulator loop. The modulator loop includes a multicast modulator that modulates the selected plurality of wavelengths with the multicast data. Each modulated wavelength is then switched back to the optical network by the 4WCS switch, and sent to a plurality of subscriber nodes of the optical network. This architecture allows a facility provider to be physically separated from a content provider, and affords the flexibility of selectively delivering multicast content to individual subscribers.

Abstract: A method and apparatus for generating an arbitrary UWB waveform are presented. An optical comb generator generates a serial stream of optical tones and an optical beating tone. A serial-to-parallel converter receives the serial tones and converts them into parallel optical tones. A spatial light modulator receives the parallel optical tones, and independently adjusts at least one of the phase and amplitude of each to generate the components of an arbitrary waveform. Next, each one of a plurality of optical-to-electrical converters receives a parallel optical tone and the selected optical beating tone, which are beat with the optical beating tone, producing electrical notes, representing differences between each parallel optical tones and the optical beating tone. Each antenna element is connected to receive an electrical note and to launch a signal based thereon, such that the launched signals are superimposed to the arbitrary waveform signal.

Abstract: An optical network is provided which comprises a plurality of optical network units (19) and optical source means (3) connected and arranged to transmit light signals to each of the plurality of optical network units (19). The optical source means (3) are capable of transmitting light signals at one or more of a plurality of different wavelengths and at least one optical network unit (19) is operable to accept more than one of the said wavelengths. Further, each wavelength of the plurality is accepted by at least one of the optical network units (19) such that each such wavelength is accepted by a different subset of optical network units (19). The optical network further comprises control means (18) operable to cause the optical source means (3) to transmit light signals at one or more selected such wavelengths corresponding to respective desired subsets of the optical network units (19).

Abstract: A communication system includes a plurality of nodes and a plurality of point-to-point links that interconnect the plurality of nodes into a network. Each node includes an optical switch to controllably route a plurality of in-ports of the optical switch into a plurality of out-ports of the optical switch. Each point-to-point link includes a free space optical channel. A first free space optical channel couples to a first node through a receive path and through a transmit path. The receive path couples to a respective in-port of the optical switch of the first node, and the transmit path couples to a respective out-port of the optical switch of the first node. In an alternative embodiment, a communication hub includes a plurality of neighborhood links to corresponding users, an optical switch coupled to the plurality of neighborhood links, and a trunk coupled between the optical switch and a free space optical channel link to the network.

Abstract: Internal communication signals in a stored program controlled system comprising a plurality of units configured to process signals are provided by a free space optical beam line which is proximal to all of the plurality of units. The free space beam line is configured to contain optically encoded signals which comprises signals transmitted between and/or among the plurality of units. Each unit includes a probe for injecting optically encoded signals in the free space beam line and/or and for receiving optically encoded signals from the free space beam line. Advantageously, there may be a first terminal at a first end of the beam line to configure to transmit and terminate the optically encoded signals and a second terminal unit at the second end of the free space beam line configured to transmit and terminate the optically encoded signals.

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: A communications network having two complementary optical networks each connectable to a headend, each optical network comprising a plurality of periodic interleaving filters serially connected by optical waveguides such that an output port of one periodic interleaving filter is couple to an input port of another periodic interleaving filter, and wherein an input or output node of the network is formed by a non-serially connected input or output port of a periodic interleaving filter.

Abstract: Generating oscillator signals with which selected signals may be mixed. Such oscillator signals may be generated by dividing a pilot tone, such as a 120 MHz pilot tone found on many cable TV systems. Oscillator signals for demodulating received selected signals may be similarly generated.

Abstract: The detection light reflection function is given to PLC type LD, PD or LD/PD modules having light guides and optoelectronic chips (LD, LED, PD or APD) by forming a grating on the light guides which selectively reflects only the detection light.

Abstract: An optical fiber network can include an outdoor laser transceiver node that can be positioned in close proximity to the subscribers of an optical fiber network. The outdoor laser transceiver node does not require active cooling and heating devices that control the temperature surrounding the laser transceiver node. The laser transceiver node can adjust a subscriber's bandwidth on a subscription basis or on an as-needed basis. The laser transceiver node can also offer data bandwidth to the subscriber in preassigned increments. Additionally, the laser transceiver node lends itself to efficient upgrading that can be performed entirely on the network side. The laser transceiver node can also provide high speed symmetrical data transmission. Further, the laser transceiver node can utilize off-the-shelf hardware to generate optical signals such as Fabry-Perot (F-P) laser transmitters, distributed feed back lasers (DFB), or vertical cavity surface emitting lasers (VCSELs).

Abstract: A passive optical star coupler, and associated method of operation arranged to transmit signals received at any input port to all output ports other than an output port associated with the input port. In this way all received signals are broadcast to all connected network equipment with the exception of the transmitting equipment.

Abstract: A network for distributing signals to a plurality of user apparatuses having a distribution unit with a plurality of ports, and a plurality of optical-fiber cables connected to the ports and suitable to make the plurality of ports of the distribution unit communicate with the plurality of user apparatuses. At least one of the plurality of optical-fiber cables is an electrically terminated optical cable having an optical cable with a single-mode optical fiber and an opto-electronic end portion mechanically and permanently connected to an end of the optical cable, and the opto-electronic end portion has an opto-electronic conversion device having an optic port optically aligned with and mechanically connected to, an end of the single-mode optical fiber.

Abstract: A technique for performance-monitoring of a standard SONET signal involves first converting the optical signal to an electrical signal, removing in the framing signal time slot the framing signal for leaving only the framing signal noise in such time slot, and separating the framing signal noise from the data signal for viewing as a measure of the quality of the SONET signal.

Abstract: A synchronization system in accordance with the principles of the invention includes a central synchronizing management unit, at least one synchronization distribution unit, and at least one network element. Each synchronization distribution unit receives synchronization and management information from the central synchronization management unit. This information may be transmitted directly from the central synchronization management unit, or it may be transmitted though another synchronization distribution unit in a group of a daisy-chained synchronization distribution units. The daisy-chained arrangement employs both active and passive optical paths. The central synchronizing management unit may query any synchronization distribution unit within the system to obtain performance statistics.

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

Abstract: The present invention provides an improved full-duplex optical communications system. The system includes: at least one office, where the at least one office provides a plurality of channels, the plurality of channels comprising a plurality of signal channels and a plurality of continuous wave (CW) channels; at least one optical add/drop multiplexer (OADM) optically coupled to the at least one office; and a subscriber premises optically coupled to the at least one OADM, where at least one of the plurality of signal channels and at least one of the plurality of CW channels are dropped from the plurality of channels to the subscriber premises by the at least one OADM, where the subscriber premises modulates the dropped at least one of the plurality of CW channels, where the modulated at least one of the plurality of CW channels is added to the plurality of channels by the at least one OADM.

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: Methods and systems for hybrid network access are provided. An analog fiber optic distribution system is provided from a central office to a remote location associated with customer premises. A central office node located at the central office is configured to transmit at least two of digital subscriber loop (DSL), cable television and/or wireless networking signals on the analog fiber optic distribution system and convert received transmissions from the analog fiber optic distribution system to the at least two of DSL, cable television and/or wireless networking signals.

Abstract: A bit synchronization circuit composed of a multiphase data sampling unit for converting each received burst data sets to multiphase data trains, a phase determination unit for generating a control signal indicating an optimum phase data train, an output data selector for selectively passing optimum phase data train indicated by the control signal, and a data synchronization unit for converting the optimum phase data train to a data train in synchronization with a reference clock. The phase determination unit repeatedly detecting the optimum phase data train during the same burst data set is received. When optimum phase varies, the output data selector dynamically switches the optimum phase data train to be supplied to the data synchronization unit.

Abstract: An optical communication system and a communication network are disclosed herein capable of transmitting optical signals with high optical launch power over long distances with suppression of stimulated Brillouin scattering. A method of transmitting optical signals is also disclosed herein which comprises transmitting optical signals at high optical launch power with a high carrier-to-noise ratio (CNR). Passive optical networks disclosed herein provide greater reach and/or increased splits.

Abstract: A system (SYS) for optically transmitting information, e.g., television signals, from a subcenter (HUB), e.g., a cable television head end, over a passive optical distribution network to a plurality of optical network units (ONU) includes a plurality of nodes (K1, . . . , Km) for optically transmitting further information, e.g., telephone signals, and a plurality of optical couplers (C1, C2). The further information of each node (K1, . . . , Km) is fed via a respective coupler (C1, C2) into a transmission line connected to only part of the plurality of optical network units (ONU), e.g., to only one optical network unit (ONU). Each optical network unit (ONU) is connected to a group of customer locations (END) and, for the transmission of information from this group of customer locations (END), via a further passive optical distribution network to a node (K1, . . . , Km). Each node (K1, . . . , Km,) includes means for separating the information received from the customer locations into, e.g.

Abstract: Disclosed relates to a wavelength division multiplexing-passive optical network (WDM-PON) system that can lock wavelengths of upstream light signals output from a plurality of optical network units (ONUs) by using coherent multi-wavelength light sources and reduce mode partition noises caused when using the coherent multi-wavelength light sources.

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: A telecommunications system includes a passive optical network (PON) including an optical splitter configured to serve optical network terminations (ONTs) at respective ones of a plurality of subscriber premises. The system further includes an optical network unit (ONU) coupled to the PON and configured to provide communications for the plurality of the subscriber premises. The optical splitter may directly subtend the ONU, and the optical splitter and the ONU may be co-located, for example, at the same pole or pedestal. The ONU may be powered by a power source located at a remote terminal (RT). A composite fiber/conductor cable may couple an optical line terminal (OLT), which may be positioned at a central office (CO) or the RT, and the power source to the optical splitter and the ONU, respectively.

Abstract: An optical network has an optical splitter connected to (1) a working optical subscriber unit (OSU) of a working circuit, (2) a protection OSU of a protection circuit, and (3) one or more optical network terminals (ONTs), where an ONT has (i) a working line termination (LT) unit of the working circuit and connected to the optical splitter via a working optical fiber and (ii) a protection LT unit of the protection circuit and connected to the optical splitter via a protection optical fiber. The present invention enables fast protection switching from the working circuit to the protection circuit. The arrival times of corresponding downstream cells are measured at both the working and protection LT units of the ONT, and information related to the arrival times is transmitted from the ONT to the protection OSU.

Abstract: A cable television system (100) having forward and reverse paths includes, in the reverse path, a digital optical transmitter (200) for receiving an RF signal, converting it to a digital signal, and adding a digital pilot tone thereto. A laser is driven in accordance with the summed digital signal to generate a digital optical signal representative of the pilot tone and the RF signal. The cable television system (100) also includes an optical receiver (305) for receiving the digital optical signal and recovering therefrom the RF signal and the pilot tone. The optical transmitter (200) and receiver (305) are coupled by fiber optic communication media (110).

Abstract: Analog video signals are communicated from multiple service providers to subscribers by using analcg optical carriers. Unlike digital optical carriers that typically support data services or IP TV, analog optical carriers that can be demodulated or translated back into the analog radio-frequency (RF) signals do not require additional and costly hardware for reception by a RF receiving device such as a television (TV) set. With the present invention, a TV set does not need significant digital hardware such as a digital set top box to allow the TV set to view video signals from a desired service provider. The present invention can allow a plurality of competing service providers to offer video services to a subscriber through a single optical network.

Abstract: Systems and methods are described for reverse digitized communications. A method includes: providing at least one optical fiber from at least one member selected from the group consisting of a headend and a hub, a minifibernode coupled to said at least one optical fiber, and an electrical conductor coupled to said minifibernode; transforming a forward optical signal from said at least one optical fiber to a forward analog electrical signal on said electrical conductor at said minifibernode; and transforming a reverse analog electrical signal on said electrical conductor to a reverse digital optical signal at said minifibernode. The systems and methods provide advantages because the need for muxnode units is eliminated, the cost of the node units is reduced, the amount of optical fiber is reduced and the reverse bandwidth is increased.

Abstract: This invention relates to optical communications and is designed for use in data transmission networks.

Abstract: This invention provides a new architecture for a communication system between head-ends and end-users which expands bandwidth and reliability of the communication system. A mux-node receives communication signals from a head-end and forwards the received communication signals to one or more mini-fiber nodes. The connection to the head-end is via a small number of optical fibers and the connections to each of the mini-fiber nodes may be via one or more optical fibers that may provide full duplex communication. The head-end may communicate with the mux-node using digital or digital and analog signals. The mini-fiber nodes may combine the signals received from the head-end with loop-back signals used for local media access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and transmitted to the mux-node.

Abstract: The present invention relates to Wavelength Division Multiplexing (WDM) based optical communications, and more particularly to an Fabry-Perot (FP) laser apparatus mode-locked to a multi-frequency lasing light source and an optical transmission apparatus using the same.

Abstract: A reconfigurable node for a hybrid fiber cable network includes fiber slots housing a transmitter or receiver interfacing to a head end, coax slots housing an RF brick interfacing with subscribers and RF plug-in modules providing connectivity between the fiber and coax slots. The plug-in modules include connection points, for connection to a fiber or coax slot. A fiber impedance element, associated with the transmitter or receiver in that fiber slot, is connected to each fiber slot. Each fiber impedance element has a different impedance value. A coax impedance element, associated with the RF brick in that coax slot, is connected to each coax slot. Each coax impedance element has a different impedance value. An impedance sensing circuit detects a DC level associated with each connection point which corresponds with the impedance element in a respective fiber or coax slot to determine the location of transmitters, receivers or RF bricks.

Abstract: A balun is constructed from a parallel pair of lines (coaxial or bifiler) that are bent to form a U-shape including a more curved (bent) section with two ends each of which are connected to a respective less curved (straight leg) section. One or more single hole ferrite beads are threaded over each respective pair of less curved sections of the pair of lines.

Abstract: A communication system includes plural nodes interconnected with an optical transmission medium capable of carrying plural bands of optical channels. A device at each node is coupled to the medium for dropping one or more bands, adding one or more bands, and passively transmitting other bands such that a pair of nodes can communicate directly using a band common to the respective bands. One band of the bands associated with each of a first set of nodes overlaps with one band of the bands associated with each of a second set of nodes. Multiple overlapping bands provide a high level of wavelength termination diversity. An optical management bus system and method connects plural hybrid optical/electrical cables between transmission equipment and optical modules which connect to network fibers to provide a set of electrical connections that can be used to determine optical interconnections in an optical shelf configuration.

Abstract: A method and system deliver multiple-band broadcast services in a network such as a wavelength division multiplexed passive optical network. In the transmitter and/or receiver of such a system, filters are cascaded to stack data corresponding to different services within different free spectral frequency ranges of an optical transmission signal. Each filter is used to select a portion of a free spectral frequency range to be delivered to a user node. Each transmitter filter confines the output from spontaneous emission sources to a desired spectral region. The cascaded filters can also combine multiple spectra and/or separate combined broadcast spectrum. The method can also be used to partition the output from a broadband spectral source into different portions in the spectral domain.

Abstract: The object is to provide an optical communication system that can improve the line status of mobile communications while making good use of existing communication infrastructures.