Abstract: The invention relates to a wavelength division multiplexing optical receiver that is provided with a polarization splitting grating coupler and a driving method for the same, where the power consumption is reduced, and at the same time, a degradation in the receiver sensitivity is suppressed. Two monitor photodetectors configured to monitor the light intensity of a first polarization component and a second polarization component separated by a polarization splitting optical coupler are provided, and a control circuit is provided in order to allow a semiconductor optical amplifier that amplifies the first polarization component and another semiconductor optical amplifier that amplifies the second polarization component in accordance with the signal intensity ratio of the two monitor photodetectors to amplify light with different light gains.

Abstract: A method (100) of operation in a passive optical network system (600) includes transmitting wave division multiplexed data in a downstream link (617) of an optical distribution network (618) using a plurality of optical line terminals (601,602,603). Each optical line terminal (601,602,603) operates at a unique wavelength, and is synchronized to each other optical line terminal by a common reference (643). Upstream data is received from an upstream link (619) of the optical distribution network on a shared common upstream wavelength (620).

Abstract: A technique for providing time division multiplexing (“TDM”) and wavelength division multiplexing (“WDM”) communication services to customer premises (“CP”) over a passive optical network (“PON”) includes multiplexing a downstream TDM signal with downstream WDM signals onto a fiber trunk line coupled between a central office and a remote node (“RN”), separating the downstream WDM signals from the downstream TDM signal at the RN with a wavelength selective filter, power splitting the downstream TDM signal at the RN onto a plurality of fiber access lines as split TDM signals; and recombining each of the WDM signals with a corresponding one of the split TDM signals onto a corresponding one of the fiber access lines.

Abstract: A method for communicating in a passive optical network (PON), includes receiving traffic from a plurality of optical network units (ONUs) transmitting in an upstream transmission channel, wherein each of the ONUs may transmit at any wavelength within a wavelength band associated with the upstream transmission channel. The method also includes dividing the upstream transmission channel into a plurality of sub-channels, that each include a subset of the wavelength band associated with the upstream transmission channel. The method further includes determining the identity of each of the plurality of ONUs transmitting in each of the sub-channels, assigning a plurality of ONUs transmitting in the upstream transmission channel to each of at least two of the sub-channels based on the determination of the ONUs transmitting in that sub-channel, and allocating transmission timeslots for time-shared transmission by the ONUs in one or more of the sub-channels.

Abstract: An apparatus comprising a time domain multiplexing (TDM) to Orthogonal Frequency Division Multiplexing (OFDM) or bounded Quadrature Amplitude Modulation (QAM) channels HOT PON converter configured to couple to an optical line terminal (OLT) via an optical fiber and to a plurality of network terminals (NTs) via a point-to-multipoint coaxial cable and configured to transmit TDM data from the OLT using OFDM or bounded QAM channels to the corresponding NTs, wherein the OFDM or bounded QAM channels transmission of TDM data maintains End-to-End (E2E) TDM passive optical network (PON) protocols, service provisioning, and quality of service (QoS).

Abstract: The disclosure provides an optical network system, an Optical Line Terminal (OLT), an Optical Network Unit (ONU) and an Optical Distribution Network (ODN) apparatus. The system includes: an OLT configured to modulate and encode at least one line of time-division-multiplexed downlink signals, synthesize the downlink signals encoded into one line and then output it, receive uplink signals, and decode the uplink signals received and then output them; an ODN configured to separate the downlink signals received into multiple lines and then output them, synthesize the uplink signals received into one line, and then output it to the OLT; and ONUs configured to receive the downlink signals output from the ODN, decode the downlink signals received and output them, encode one line of time-division-multiplexed uplink signals, and output the uplink signals encoded to the ODN. Decoding of the downlink signals and encoding of the uplink signals can further be implemented by the ODN.

Abstract: The present invention relates to an open optical access network system in which one optical access network is open to enable a plurality of service providers and a plurality of subscribers to simultaneously use the optical access network, to thereby improve the efficiency of using the optical access network, wherein each subscriber can be provided with a plurality of different services from the plurality of service providers, thereby enabling the flexible selection of services and the flexible change in services, thus improving the efficiency of using an optical infrastructure.

Abstract: A coherent optical receiver circuit is disclosed in which various components of the optical receiver may be provided or integrated, in one example, on a common substrate. Further integration is achieved by incorporating various optical demultiplexer designs that are relatively compact and conserve space on the surface of the substrate. The optical receiver circuit may be used to demultiplex quadrature phase shift keying (QPSK) optical signals.

Abstract: A passive optical network (PON) component comprising a processor coupled to a plurality of receivers, the processor configured to monitor a plurality of drifting laser wavelengths and cause the drifting laser wavelengths to be tuned to a plurality of pass-bands. Also disclosed is an optical network unit (ONU) comprising a receiver, a transmitter coupled to the receiver, and a partially-tunable laser coupled to the transmitter and having a drifting laser wavelength, wherein the drifting laser wavelength is periodically tuned to one of a plurality of pass-bands. Included is a method comprising monitoring a plurality of drifting laser wavelengths associated with a plurality of pass-bands, and reconfiguring a plurality of time division multiple access (TDMA) timeslots when one of the drifting laser wavelengths migrates from one pass-band to another pass-band.

Abstract: A wavelength division multiplexer is provided by the present invention, which implements the wavelength division multiplexing and de-multiplexing of the optical signals in the basic and upgrade bands by reasonably arranging the filters and selecting the spectral properties of the filters, so that the existing time division multiplexing passive optical network (TDM-PON) can transmit the next generation passive optical network (NG-PON) simultaneously and the existing TDM-PON can be smoothly upgraded to the NG-PON, meanwhile, it provides the deployed TDM-PON with the subsequent network compatibility. The wavelength division multiplexer provided in the present invention can meet the high isolation requirement of the optical signals in working band with low cost, and takes both the isolation requirement and the optical network insertion loss requirement into account, thus it has high reliability, is easy to use and for system upgrade.

Abstract: A Multiple-Input-Multiple-Output (MIMO) data transmit-receive protocol that can be used with an arbitrary light array, including one or more lights, that transmits light to a light receiver having an image sensor, including a large number of light sensing pixels. The protocol supports two primary protocol or coding modes in which the light array may transmit: spatial coding and space-time coding. The protocol is constructed upon the use of efficient start-frame-delimiters (SFDs) and data-delimiters (DDs). The lights may be implemented to transmit the SFDs, the data delimiters, and data bits as modulated light. The light may be modulated in accordance with a modulation technique referred to as frequency shift on-off keying (FSOOK).

Abstract: Systems, methods, and computer-readable media for propagating a timing signal over a Dense Wave Division Multiplexer fiber optic network by polarity modulation of the Optical Service Channel are provided. The systems, methods, and computer-readable media may make the timing signal available for use by devices that require a reference timing source.

Abstract: A burst transmission method and a receiver resetting method and apparatus in a Passive Optical Network (PON) are provided. A burst receiver resetting method in a PON includes: receiving a preamble sequence and synchronizing data; after synchronizing the data, continuing to receive the data, and matching a Burst Terminator (BT); and resetting a receiver after successfully matching the BT. Meanwhile, an apparatus for implementing the method and a corresponding burst data transmission method are provided. By using the burst receiver resetting method and apparatus in the PON and the corresponding burst transmission method at an Optical Network Unit (ONU) burst transmission end, a Reach Extender (RE) does not need to unpack upstream burst bandwidth allocation information carried in downstream data. Therefore, the complexity of the implementation of the RE is reduced, and the method is simple and effective.

Abstract: An optical frequency-division multiplexer includes: a first optical coupler configured to receive a first wavelength-division multiplexed light obtained by wavelength-division multiplexing a first carrier light and a first monitor light and split the first carrier light and the first monitor light from each other; an optical modulator configured to optically modulate the split first carrier light using a signal including a first data signal so as to multiplex the first data signal with the first carrier light; a receiver configured to receive a branched part of the split first monitor light and demodulate a second data signal from the first monitor light; and a second optical coupler configured to couple a remaining part of the split first monitor light and the first carrier light with which the first data signal has been multiplexed.

Abstract: An optical add-drop network and wavelength allocation for the same wherein the system bandwidth is separated into a dedicated channel band and re-used channel bands, separated by guard bands, to allocate terminal connections to achieve a minimum number of re-used channel bands for the desired terminal connectivities.

Abstract: A PON in which parallel optical fiber paths are provided between dual OLTs and the ONTs, one of the optical fiber paths providing an active connection and the other optical fiber path providing a standby connection. Respective VLANs may be formed over the parallel optical fiber paths. If performance indicators, for example Ethernet continuity check messages, indicate that an ONT is no longer in communication with the OLT then data may be sent via the VLAN associated with the standby connection.

Abstract: An optical multi-wavelength transmitter comprising an optical interleaver with at least a first optical waveguide and a second optical waveguide; a first plurality of microcavity modulators coupled to the first optical waveguide and a second plurality of microcavity modulators coupled to the second waveguide. A plurality of optical wavelengths received at an input of the interleaver are separated into a first group of separated optical wavelengths for being input in the first optical waveguide and a second group of separated optical wavelengths for being input in the second optical waveguide. Each one of the first and the second group of separated optical wavelengths have a separated wavelength spacing between adjacent separated optical wavelengths. A method of optical multi-wavelength transmission is also disclosed.

Abstract: One or more overlay wavelengths are applied to a GPON architecture to provide sufficient, cost-effective forward bandwidth per home for targeted, unique narrowcast services to allow traditional HFC operators to use a PON architecture with their existing HFC equipment. A separate return path capability using a separate coaxial cable with RF signals to the GPON may also be used. This return capability may be provided either by a fiber optic link or coaxial link from the home.

Abstract: A quantum cryptography communication apparatus performs quantum cryptography communication between a transmitter and a receiver. The quantum cryptography communication apparatus includes first communicating unit transmitting and receiving a communication signal including relatively strong pulse light between the transmitter and the receiver, and second communicating unit transmitting and receiving a relatively weak quantum cryptography signal between the transmitter and the receiver in a period in which the communication signal is off and the attitude axis for the receiver can be adjusted to that for the transmitter by the second communicating unit.

Abstract: The present invention provides a method and system for transmitting data over an optical channel using OFDM with a variable transmission rate. Such method and system feeds an essentially constant transmission power over a predetermined OFDM bandwidth into the optical channel. In an embodiment, at least two OFDM subcarriers may be modulated with signal information derived from a single word of an OFDM symbol. Further thereto, the frequency spacing between the transmitted OFDM subcarriers may be changed.

Abstract: A method, apparatus and system for aligning frames in which an Optical Network Unit (ONU) receives a frame comprising frame delimitation information and synchronization-related information; performs a first verification based on a comparison of the frame delimitation information and a fixed pattern; performs a second verification based on a comparison of the synchronization-related information and a value associated with synchronization-related information in a previously received frame; proceeds to a synchronization state if both the first verification and the second verification are successful; and returns to a hunt state if either the first verification or the second verification fails.

Abstract: One embodiment provides an EPON for transporting RF signals. The system includes a reference clock, an ONU, and an OLT. The ONU includes a mechanism for receiving a frequency and phase-reference signal from the OLT, a mechanism for receiving an RF signal, an ADC for converting the RF signal into a digital signal using a sampling signal associated with the frequency and phase-reference signal, a mechanism for assembling at least a portion of the digital signal into a packet, a mechanism configured to timestamp the packet, and an optical transceiver. The OLT includes a mechanism for receiving the packet, a buffer, a delay mechanism configured to delay reading the received packet from the buffer for a predetermined amount of time, and a DAC for converting the digital signal included in the packet back to RF domain using a clock signal associated with the frequency and phase-reference signal.

Abstract: Consistent with the present disclosure, a polarization multiplexed optical signal having optical signals with both TE and TM polarizations is supplied to an input of a polarization beam splitter (PBS). The PBS includes a first output that supplies TE polarized optical signals and a second output supplies TM polarized optical signals. A first polarizer is coupled to the second output of the PBS to pass the TM polarized optical signals, while rejecting light having other polarizations, such as the TE polarization. A rotator then rotates the light output from the first polarizer, so that such light has a TE polarization. A second polarizer is coupled to the rotator to filter light having a polarization other than the TE polarization. In addition, a third polarizer is coupled to the first output of the PBS in order to filter or block any TM light, for example, that may be output from the PBS with the TE polarized signal.

Abstract: In accordance with the teachings of the present invention, a system and method for extending reach in a passive optical network (PON) is provided. In a particular embodiment, a method for extending reach in a PON includes transmitting traffic at a first wavelength from a transmitter at a first optical network unit (ONU) in a PON and transmitting traffic at a second wavelength from a transmitter at a second ONU in the PON. The method also includes receiving the traffic in the first wavelength at a first input port of a multiplexer at a distribution node in the PON and receiving the traffic in the second wavelength at a second input port of the multiplexer at the distribution node. The method further includes forwarding the traffic in the first wavelength and the traffic in the second wavelength to an optical line terminal (OLT) in the PON.

Abstract: A radio-over-fiber (RoF) hybrid wired/wireless transponder is disclosed that is configured to provide both wireless and wired communication between a hybrid head-end and one or more client devices. The hybrid transponder includes optical-to-electrical (O/E) and electrical-to-optical (E/O) conversion capability and is configured to frequency multiplex/demultiplex electrical “wired” signals and electrical “wireless” signals. The electrical wireless signals are wirelessly communicated to the client device(s) via a multiple-input/multiple-output (MIMO) antenna system within a cellular coverage area. The electrical wired signals are communicated to the client device(s) via a wireline cable that plugs into a wireline cable port on the transponder. The hybrid RoF system includes a hybrid head-end capable of transmitting and receiving wired and wireless optical signals, and an optical fiber cable that is optically coupled to the hybrid head-end and to at least one hybrid transponder.

Abstract: An OLT transmits and receives a CMTS/CM apparatus control signal through an apparatus physical management interface which is physically identical to or different from a main signal interface (NNI) and processes the CMTS apparatus control signal by itself. When connection of a new ONU is detected by an ONU apparatus control signal, an IP address is allocated by using the CM apparatus control signal in a manner similar to the CM. The CM apparatus control signal regarding the ONU is transmitted and received by using the IP address and a mutual conversion is performed between the CM apparatus control signal and the ONU apparatus control signal. The ONU processes the ONU apparatus control signal in a manner similar to the ONU based on an ordinary PON standard.

Abstract: An OLT transmits and receives a CMTS/CM apparatus control signal through an apparatus physical management interface which is physically identical to or different from a main signal interface (NNI) and processes the CMTS apparatus control signal by itself. When connection of a new ONU is detected by an ONU apparatus control signal, an IP address is allocated by using the CM apparatus control signal in a manner similar to the CM. The CM apparatus control signal regarding the ONU is transmitted and received by using the IP address and a mutual conversion is performed between the CM apparatus control signal and the ONU apparatus control signal. The ONU processes the ONU apparatus control signal in a manner similar to the ONU based on an ordinary PON standard.

Abstract: A passive optical network system includes: a plurality of optical signal splitter receiving optical signals from a plurality of optical network units (ONUs) to provide a plurality of upstream optical signals having different wavelengths; a hybrid optical filter multiplexing the plurality of upstream optical signals in a wavelength division multiplexing (WDM) scheme; and an optical line terminal (OLT) receiving the multiplexed upstream optical signals in a time division multiplexing (TDM) scheme. Therefore, the network system can be easily expanded when the number of subscribers increases, and the optical loss can be minimized.

Abstract: A communication equipment which is utilized in a power line communication (PLC) system utilizing a hybrid fiber coax (HFC) which includes a PLC optical network unit, a PLC trunk bridge amplifier, a PLC distribution amplifier, and a PLC coupling device. In this instance, the PLC optical network unit does not require a PLC protocol conversion of an Ethernet signal by a cable modem and a PLC modem in each subscriber location, and enables a PLC communication between the each subscriber location and a communication terminal utilizing a PLC Ethernet signal as is, by receiving an optical signal from an optical transmitter via an optical fiber, converting the optical signal into the PLC Ethernet signal corresponding to a predetermined PLC protocol, and transmitting the PLC Ethernet signal to at least one subscriber location via a coaxial cable.

Abstract: An exemplary apparatus for digital coherent detection of a multi-wavelength signal includes a polarization-diversity optical hybrid, at least four Wavelength De-Multiplexing (W-DMUX) filters, 4M detectors, and 4M analog-to-digital converters (ADCs), with M an integer greater than one. The hybrid has a first input for receiving a multi-wavelength signal including M sub-channels at different wavelengths, and a second input for receiving a reference light source including M continuous-wave references at different wavelengths that approximates center wavelengths of the M sub-channels. The hybrid has at least four outputs. A W-DMUX input for each W-DMUX filter is provided a corresponding one of the hybrid outputs, and each W-DMUX filter provides M filtered optical channel outputs. Each detector converts at least one of the filtered channel outputs into a corresponding electrical signal. Each ADC converts one of the electrical signals into a corresponding digital signal.

Abstract: Embodiments of the present invention provide a systems, devices, and methods in which a client signal is divided into a plurality of channels, mapped within transport frames, and combined into a WDM transport signal. These embodiments include intra-nodal redundancy that protects against failure events within the transport transmitter. In particular, redundancy is provided within a network transport transmitter such that redundant paths are available so that electrical channels may be routed around a malfunctioning component within the transmitter.

Abstract: A multiservice private network and interface modules (M1-M5). Each of said modules is dedicated to interfacing a specific terminal equipment (T1-T4, GTW; 310-380) in the multiservice private network. The interface modules (M1-M5) are connected to the terminal equipment on a one-to-one basis. Each interface module (M1-M5) is configured to send and/or receive data in a format adapted to the terminal equipment to which it is connected, at a specific wavelength, in order to interconnect, via said private network, at least two mutually compatible terminal equipments among all the terminal equipments. This arrangement is typically applicable in particular to interconnecting, via a common network, heterogeneous different terminal equipments, so that the mutually compatible terminals communicate directly with one another without interfering with communication between other terminals of a different type.

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: Digital information can be carried on the fiber leg of an access network using binary modulation. Binary modulated data received at an O/E node can then be modulated onto an analog waveform using quadrature amplitude modulation or some other technique for modulating an analog waveform and transmitted over, for example, the coaxial leg of the network. The O/E node may also receive an analog signal, over the coaxial leg, modulated to carry upstream data from subscriber devices. The O/E node may demodulate the upstream signal to recover the upstream data and forward that upstream data over the fiber leg using a binary modulated optical signal.

Abstract: This is a method for use in architecting low cost networks using a thin optical transport layer. A long reach hot pluggable interface is inserted onto an electrical switch resulting in a standardization of the optical layer. Standardized parts like the long reach hot pluggable interfaces and standard control planes form the logic that connects components of the low cost optical layer. After the components are in place, provisioning is done at end points only. This ensures an automatic and fast turn-up capacity without the need to visit intermediate sites in the network.

Abstract: A passive optical network communication system transmits an optical time-division multiplexed signal from a central office through a passive optical coupler to a number of subscribers, and transmits optical encoded signals from the subscribers through the passive optical coupler to the central office. Optical encoded signals from different subscribers are separated by a decoding process performed at the central office. All operations can be synchronized with a clock signal which is generated at the central office and recovered from the optical time-division multiplexed signal by the subscribers' equipment. The communication range can be extended inexpensively by using a single high-power light source at the central office while using relatively low-power light sources at the subscribers' equipment.

Abstract: A system according to embodiments of the invention may comprise a first communication path that converts an optically-modulated source signal to a radio signal based on a detected degradation in a quality of a received optical signal, and a second communication path that converts a radio-modulated source signal to an optical signal based on a detected degradation in a quality of a received radio signal. The system may therefore adapt to diverse weather conditions to improve the reliability of a communication link.

Abstract: In accordance with the teachings of the present invention, a system and method for managing different transmission architectures in a passive optical network (PON) is provided. In a particular embodiment, a method for managing different transmission architectures in a PON includes transmitting traffic in an upstream or downstream direction in a first time-slot in a PON at each channel of a first set of one or more channels. The method also includes transmitting traffic in the same upstream or downstream direction in a second time-slot in the PON at each channel of a second set of one or more channels that provide greater bandwidth than the first set of one or more channels, wherein at least one channel of the first set at least partially overlaps at least one channel of the second set but is not identical to the at least one channel of the second set.

Abstract: In accordance with the teachings of the present invention, a system and method for managing communication in a hybrid passive optical network (HPON) is provided. In a particular embodiment, the method includes transmitting, at a first wavelength, a first configuration message on the HPON. The method also includes receiving at one or more of a plurality of receivers at an optical line terminal (OLT) one or more configuration response messages from one or more optical network units (ONUs) in a first set of ONUs. The method further includes, based on the configuration response messages from the first set of ONUs, associating, in a database, each ONU in the first set of ONUs with the first wavelength and with the receiver receiving the configuration response message from the ONU. The method also includes, after transmitting the first configuration message, transmitting, at a second wavelength, a second configuration message on the HPON.

Abstract: In an optical receiver according to the present invention, an input signal light subjected to the differential quadrature phase shift keying (DQPSK) is incident on a PANDA type fiber in a linearly polarized state by 45°, so that a delay time difference corresponding to one symbol is generated between orthogonal polarization components in the DQPSK signal light, and then, the signal light is branched by a half mirror into two, to be sent to first and second paths respectively, thereby giving, by a ¼ wave plate disposed on one of the paths, a relative birefringent amount difference of ?/2 between the lights propagated through the respective paths. Then, each of the lights propagated through the first and second paths is separated into two orthogonal polarization components by a polarization beam splitter, and the respective polarization components are received by a differential reception circuit so that in-phase components and quadrature components in the DQPSK signal are demodulated.

Abstract: The present invention discloses a receiver for optical system, which provides improved performance due to implementation of multiple parallel analog-to-digital converters. Such configuration allows reducing the data speed processing thus improving bit-error-rate. Each channel of the WDM communications system consists of a set of orthogonal spectral bands. These bands are modulated via orthogonal frequency division multiplexing (OFDM) technique using M-PSK modulation format. At the receiver side, the incoming optical beam is split into a set of parallel branches. Each branch is mixed with a local oscillator beam having a spectrum within one sub-band of the WDM channel. In the preferred embodiment these beams are mixed in 90-degrees optical hybrid, which is followed by a set of balanced photodetectors. The baseband of each sub-band signal is converted into a digital signal using ADC.

Abstract: A method and apparatus for transmitting signals from a plurality of input channels over a TDM optical network, where each of the input channels contains an optical data signal and an electrical control signal containing control information relating to the optical data signal. In accordance with the invention, respective optical receivers convert the optical data signals to respective electrical data signals, which a TDM data multiplexer time-multiplexes to generate a multiplexed data signal. A TDM control signal multiplexer time-multiplexes the electrical control signals to generate a multiplexed control signal that is combined with said multiplexed data signal to generate a composite electrical signal. An optical transmitter generates a composite optical signal from the composite electrical signal that is transmitted over the network, optionally after WDM multiplexing it with other composite optical signals.

Abstract: Apparatus and system for transmitting and receiving optical code division multiple access data over an optical network. The apparatus comprises a spectral phase decoder for decoding the encoded optical signal to produce a decoded signal, a time gate for temporally extracting a user signal from the decoded signal, and a demodulator that is operable to extract user data from the user signal. The system preferably comprises a source for generating a sequence of optical pulses, each optical pulse comprising a plurality of spectral lines uniformly spaced in frequency so as to define a frequency bin, a data modulator associated with a subscriber and operable to modulate the sequence of pulses using subscriber data to produce a modulated data signals and a Hadamard encoder associated with the data modulator and operable to spectrally encode the modulated data signal to produce an encoded data signal.

Abstract: Methods and apparatus are described for transmitting and receiving data. A method includes a process of transferring data over a coaxial network at a bandwidth above 1000 MHz, wherein the process of transferring data transfers the data between an optical node and a plurality of cable modems of a hybrid fiber-coaxial cable network. An apparatus includes a data transfer system which sends and receives data over a coaxial network at a bandwidth above 1000 MHz, wherein the data transfer system is located at an optical node of a hybrid fiber-coaxial cable network.

Abstract: An OCDM signal generation section generates an encoded optical pulse signal by encoded an optical pulse signal. The encoded optical pulse signal is then inputted to a wavelength disperser and the time waveform of the encoded optical pulse signal is shaped to be outputted as a shaped and encoded optical pulse signal. A WDM signal generation section generates an optical wavelength division multiplexing signal. A OCDM signal extraction section then decodes the OCDM reception signal by using the same code as the time-spreading/wavelength-hopping code for each channel and generates a decoded OCDM reception signal.

Abstract: A communication system between head-ends and end-users is provided which expands bandwidth and reliability. A concentrator receives communication signals from a head-end and forwards the received communication signals to one or more fiber nodes and/or one or more mini-fiber nodes. The concentrator demultiplexes/splits received signals for the mini-fiber nodes and the fiber nodes and forwards demultiplexed/split signals respectively. The mini-fiber nodes may combine signals received from the head-end with loop-back signals used for local medium access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and/or fiber node and transmitted to the concentrator. The concentrator multiplexes/couples the mini-fiber node and the fiber node upstream signals and forwards multiplexed/coupled signals to the head-end.

Abstract: A technique for asymmetric transport is disclosed. In one particular exemplary embodiment, the technique may be realized by/as a method for asymmetric transport. The method may comprise transmitting, from a network element, at least one first signal through at least one first transport interface at a first rate, where the at least one first transport interface accommodates the transmission of the at least one first signal through an optical medium. The method may also comprise receiving, at the network element, at least one second signal through at least one second transport interface at a second rate different from the first rate, where the at least one second transport interface accommodates the reception of the at least one second signal through the optical medium. At least one of the at least one first transport interface and the at least one second transport interface may be integrated with the network element.

Abstract: An optical device is provided with first and second inputs. A first coupler coupled is coupled to the first input and produces at least a first and second output. A second coupler is coupled to the second input and produces at least a first and second output. A third coupler is coupled to the first output of the first coupler and to the first output of the second coupler. A fourth coupler is coupled to the second output of the first coupler and to the second output of the second coupler. First and second crossing waveguides are provided with an angle selected to minimize crosstalk and losses between the first and second cross waveguides. The first crossing waveguide connects one of the first or second outputs from the first coupler with an input of the fourth coupler. The second crossing waveguide connects one of the first or second outputs from the second coupler with an input of the third coupler. A first phase shifter is coupled to the first and second waveguides.

Abstract: The present invention is an optical multiplex communication system in which an optical wavelength division channel and an optical code division channel can coexist, wherein a WDM channel section 86 has a wavelength demultiplexer 36 and WDM channels W1 to W4. An optical pulse string 83-3 is demultiplexed by the wavelength demultiplexer 36, and for channel W1, an optical pulse 37 with wavelength ?1 is input to an intensity modulator 114 and converted into an optical pulse signal of channel W1, and is output as a wavelength division optical pulse signal 115, where transmission information of channel W1 is reflected.

Abstract: A system according to embodiments of the invention may comprise a first communication path that converts an optically-modulated source signal to a radio signal based on a detected degradation in a quality of a received optical signal, and a second communication path that converts a radio-modulated source signal to an optical signal based on a detected degradation in a quality of a received radio signal. The system may therefore adapt to diverse weather conditions to improve the reliability of a communication link.