Abstract: Bidirectional data signals are exchanged between a central unit and a plurality of network terminals. The optical carrier frequencies of the downstream and upstream signals are chosen so that reflections do not interfere with the selected signal at the optical network unit and not with the received upstream signals at the central unit. The optical network units select their associated downstream signal and generate an associated upstream signal.

Abstract: A method for transmission of multiple, independent data packages across a single optical fiber utilizing both time division multiplexing and wavelength division multiplexing is described. The method includes transmitting a first data package across the single optical fiber at a first wavelength and transmitting a second data package across the same optical fiber at a second wavelength, in either the same direction or in a direction opposite as the first data package, wherein the second data package transmission may be concurrent with the first data package transmission. the method further includes separating the data package transmissions into two optical paths, filtering the second wavelength from a first of the two optical paths, detecting the first data package at the first wavelength, filtering the first wavelength from a second of the two optical paths, and detecting the second data package data at the second wavelength.

Abstract: A radio over fiber link apparatus for transmitting/receiving radio frequency up/downlink signals in a TDD mobile communication system. The radio over fiber link apparatus includes a center site for receiving radio frequency signals from an access point of the mobile communication system. The center site has a first electro-optic converter for converting the radio frequency signals into optical signals, bias control of the first electro-optic converter being performed based on the switching of TDD signals; and a remote for transmitting the radio frequency signals to a mobile communication terminal through an antenna. The remote site has a first photoelectric converter for converting the optical signals transmitted through an optical fiber from the center site into radio frequency signals.

Abstract: D-shaped POFs are used to form a 2-to-1 optical coupler. The D-shaped POFs are produced via an extrusion process that is relatively inexpensive to perform and that can be performed with relatively high manufacturing throughput. The D-shaped POFs are bonded together to form a coupler end face having a generally circular cross-sectional area. The coupler end face is interfaced with an end face of a main POF that is generally circular in cross-sectional shape. The resulting D-shaped 2-to-1 optical POF couplers have relatively low insertion loss and relatively high optical coupling efficiency.

Abstract: Gigabit Ethernet connectivity is realized using off-the-shelf GIGABIT INTERFACE CONVERTER transceivers, wave division multiplexer/demultiplexers, and a single optical fiber. Simultaneous and bi-directional optical communication over a single optical fiber connecting two or more nodes is achieved by using at least one GIGABIT INTERFACE CONVERTER transceiver having at least one optical signal output and an optical signal input that are of different wavelengths from each other.

Abstract: A method for the contactless transmission of at least one differential signal between a transmitter and a receiver given the existence of at least one common-mode noise signal, which has a low frequency in comparison with at least one signal to be transmitted, is provided. The suppression of at least one common-mode noise signal within the receiver a ground reference potential assigned to the receiver is separated into two ground reference potentials decoupled from one another. At least one common-mode noise signal may be suppressed by a filter unit at the input of a receive amplifier of the receiver.

Abstract: An extender box (EB) includes: a downlink data sending module configured to send downlink data to first passive optical network (PON) devices; at least two uplink data receiving modules configured to receive uplink data sent from a corresponding first PON device respectively; and a duplexer configured to convert the data transmission mode used by the downlink data sending module and the uplink data receiving modules from dual-fiber transmission to single-fiber transmission to implement single-fiber bidirectional transceiving. The uplink data receiving modules have ports corresponding to uplink ports of the first PON devices on a one-to-one basis. Optical fibers of the uplink data receiving modules that are connected with the uplink ports of the first PON devices are separated from optical fiber of the downlink data sending module, where the optical fiber is connected with downlink ports of the first PON devices. A data transmission method and a PON system are also disclosed.

Abstract: A network interface apparatus comprises a bidirectional optical signal port, an optical diplexer connected to the bidirectional optical signal port, a first RF signal port (bidirectional), a second RF signal port, a first RF diplexer, and an RF splitter. The RF diplexer transmits a first received RF input signal from the first RF signal port to the optical diplexer to modulate an optical output signal transmitted by the optical diplexer to the optical signal port. The RF splitter receives from the optical diplexer an RF signal derived from an RF-modulated optical input signal received from the bidirectional optical signal port, transmits a first portion of the derived RF signal as a first RF output signal to the first RF signal port through the first RF diplexer, and transmits a second portion of the derived RF signal as a second RF output signal to the second RF signal port.

Abstract: A communication network access device is adapted for duplex communication and provides transmit and receive signal paths. A controllable socket is coupled to the transmit and receive signal paths and linked to a control interface for activating/deactivating the control interface. A pluggable module is coupled to the transmit and receive signal paths via the controllable socket in an activated status and to a transmission path carrying uni-directional signals. The module includes a first optical device and a splitter in the transmission path and is coupled to a second optical device via the splitter. The second optical device responds to a portion of uni-directional signals provided by the splitter for placing the communication access device in a link up condition for uni-directional signals provided by the first optical device to the transmission path serving an optical local area network.

Abstract: A method of initiating a set up process for a call between users with reduced set up times using one or more 3G telecommunication networks. The method is provided between at least a pair of H.324-like terminals coupled to the one or more 3G telecommunication networks. The method includes establishing a bearer channel between a first terminal and a second terminal after a call signaling process, transmitting a first FSS message from the first terminal to the second terminal. The first FSS message includes a first preference profile associated with a first mode of operation for the call and a second preference profile associated with a second mode of operation for the call. The method also includes selecting either the first mode of operation or the second mode of operation.

Abstract: Embodiments of a system are described. This system includes an array of chip modules (CMs) that are configured to communicate data signals with each other via optical communication. In a given CM module, optical signal paths, such as waveguides, are routed in the same way as in the other CMs in the array. In this way, a common optical design in the CMs may be used in the system to prevent data conflicts during the optical communication.

Abstract: A half-duplex, single-fiber (S-F) optical transceiver module is provided in which a light source, such as a laser diode or a light-emitting diode (LED), is mounted on an edge region of a photodiode to increase the amount of surface area of the photodiode that is available for absorbing light received in the optical transceiver module. The S-F optical transceiver module has a relatively simple optical coupling system for coupling light between an end face of an optical fiber and the photodiode and laser diode or LED with high optical coupling efficiency and reduced optical crosstalk.

Abstract: A small form factor pluggable (SFP) optical transceiver module and method for performing optical communications are provided. The SFP optical transceiver module has a housing to which a duplex receptacle is secured. The duplex receptacle has a C-shaped opening, the upper and lower portions of which are defined by upper and lower flexible retaining elements for receiving and retaining a duplex optical connector therein. An electrical assembly of the module is secured within the transceiver module housing. The electrical assembly comprises a PCB, the back end of which is configured as a plug end for removably plugging the PCB into a receptacle of an external communications management system.

Abstract: A duplex optical fiber link is provided that includes two bi-directional optical fiber links. Each of the bi-directional links includes a multimode optical fiber and an optical transceiver connected to each of the ends of each of the fibers. Each of the optical transceivers includes a bi-directional optical multiplexer (MUX) that is configured to simultaneously optically couple optical data signals produced by a laser diode of the transceiver into an end of one of the fibers and to optically couple an optical data signal passing out of the end of one of the fibers onto a photodiode of the transceiver. The laser diodes operate at a data rate of at least 10 Gb/s such that each optical transceiver transmits and receives optical data signals at an aggregate data rate of at least 20 Gb/s. Consequently, the bi-directional duplex optical link has an aggregate data rate of at least 40 Gb/s.

Abstract: The present invention discloses a bidirectional transmission network apparatus based on a tunable rare-earth-doped fiber laser source. It is useful in wavelength-division-multiplexing access networks. The fiber ring laser not only generates downstream data traffic but also serves as the wavelength-selecting injection light source for the Fabry-Pérot lasers (or vertical cavity surface emitting lasers) located at the subscriber site. The fiber laser is constructed based on optical filtering, polarization control and noise suppression techniques.

Abstract: A distributed antenna system is provided for communicating with a plurality of base stations. The distributed antenna system includes a system controller and a master unit communicating with at least one of the plurality of base stations. A remote unit communicates over a high data rate media with the master unit and/or a downstream remote unit. Alternatively, the distributed antenna system includes a controller and a digital time/space crosspoint switch controlled by the controller. A digitizing transceiver is in communication with the digital time/space crosspoint switch. The crosspoint switch is configured to transmit and receive digital data through the digitizing transceiver.

Abstract: A small form factor pluggable (SFP) optical transceiver module and method for performing optical communications are provided. The SFP optical transceiver module has a housing to which a duplex receptacle is secured. The duplex receptacle has a C-shaped opening, the upper and lower portions of which are defined by upper and lower flexible retaining elements for receiving and retaining a duplex optical connector therein. An electrical assembly of the module is secured within the transceiver module housing. The electrical assembly comprises a PCB, the back end of which is configured as a plug end for removably plugging the PCB into a receptacle of an external communications management system.

Abstract: ONU 2A for P-P includes a signal-type discriminating unit 22A that discriminates whether a type of a downstream signal transmitted from OLT is for the P-P or not, and outputs an enable/disable control signal that controls an optical transmitter to an enable state or a disable state, and a control unit 21 that controls the optical transmitter to the enable state or the disable state according to the enable/disable control signal, wherein the signal-type discriminating unit 22A outputs to the control unit 21 a disable control signal that controls the optical transmitter to the disable state under an initial state before the type of the downstream signal is discriminated, and outputs to the control unit 21 an enable control signal that controls the optical transmitter to the enable state after the downstream signal is discriminated to be for the P-P.

Abstract: A single wavelength bi-directional RoF link apparatus for signal transmission in a TDD wireless system includes a main donor for receiving an RF signal of downstream data from an upper layer, electrooptic converting the received RF signal to an optical signal, and transmitting the converted optical signal via an optical fiber in response to a TDD switching signal received from the upper layer, or receiving an optical signal of upstream data via the optical fiber, opto-electric converting the received optical signal to an RF signal in response to the TDD switching signal received from the upper layer, and transmitting the converted optical signal to the main donor; and a remote for receiving the optical signal of the downstream data via the optical fiber from the main donor, opto-electric converting the received optical signal to an RF signal, and emitting the converted RF signal to a terminal via an antenna in response to a TDD switching signal generated by a switch timing signal generation circuit, or receiv

Abstract: Provided is an optical access network capable of realizing protection control without affecting an E-PON for providing an Ethernet service. In the optical access network comprising the E-PON having a transmission line which is duplexed between an OLT and a plurality of ONTs, the OLT includes a layer-2 (L2) control section in which a protocol, in which protection control information is provided, as a protocol structure, above an Ethernet media access control (MAC), is mounted. Further, the OLT has a protocol structure in which the protection control information is provided independently from the Ethernet MAC to transfer user data and the protection control information.

Abstract: A method for performing a protection in passive optical networks. The method comprises forming a protection maintenance link between an active optical line terminal (OLT) and a standby OLT; forming a synchronization link between the active OLT and the standby OLT; computing a base differential distance value; continuously measuring round trip time (RTT) values by the active OLT using the protection maintenance link; periodically sending at least RTT values calculated by the active OLT to the standby OLT over the synchronization link; and computing, by the standby OLT, a new RTT value based on at least a RTT value measured by the active OLT and a standby differential distance value, when a switch-over action is triggered, thereby allowing the standby OLT to serve optical network units (ONUs) in the PON without performing a ranging process.

Abstract: Embodiments of the present invention provide a method for transmitting data, a Coaxial-cable Line Terminal (CLT) and a Coaxial-cable Network Unit (CNU). The method, applicable to a coaxial network including at least one Coaxial-cable Line Terminal (CLT) and multiple Coaxial-cable Network Units (CNUs), the CLT being connected with each of the CNUs through a shared coaxial medium, includes: transmitting, by the CLT, a control message to each of the CNUs. The control message contains information of an uplink transmission period of time that can be occupied by each CNU during one period, and uplink transmission periods of time for the CNUs are not overlapped with one another so that uplink data transmitted by the CNUs do not collide with each other. The embodiments of the present invention allocate a shared transmission medium in an EPCN system, and guarantee normal physical layer communications of the EPCN system.

Abstract: A network interface unit (NIU) for a modular workstation includes a housing. One or more input network adapters on the housing receive input connectors of a first multi-network cable that is connected to a distribution network. One or more output network adapters on the housing receive output connectors of a second multi-network cable that is connected to another NIU of another modular workstation to provide for a daisy chain connection. One or more workstation adapters are provided on the housing for providing connections to one or more networks of various security levels. Cables that are connected to one or more CPUs or telephones of the workstation are connected to respective ones of the workstation adapters. The workstation adapters of the NIU may provide one or more of visual, physical, and geographical verification and segregation of the network connections to enhance the integrity of the security of the various networks available at the NIU.

Abstract: A transmission device having optical fiber high definition digital audio-video data interface (HDMI/DVI/UDI), in which optical fiber is utilized as the physical connection for the logical channels of the transmission device, and is used to carry images, voices and auxiliary data of the logic channels. For the half-duplex transmission mode utilized by the display data channel, the reverse unit, the serial unit, and the multi-serial unit are properly arranged, thus fulfilling the DC balance requirement of optical fiber transmission, and resolving the lower tolerance rate shortcomings of the I2C bus specification of display data channel (DDC) and the customer electronics control (CEC) channel.

Abstract: A remote access unit (RAU) apparatus, coupled to a central station (CS) of an RoF network through at least one optical fiber, and which RAU apparatus includes at least one antenna, includes: first and second antenna ports coupled to the at least one antenna; first and second optical fiber ports coupled to the at least one optical fiber; a first coupler for decoupling a first downstream signal of a first duplexing method and a second downstream signal of a second duplexing method, which are input through the first optical fiber port; a circulator for outputting the first downstream signal input from the first coupler to the first antenna port and outputting a first upstream signal of the first duplexing method input from the first antenna port to the second optical fiber port; and a second coupler for outputting the second downstream signal input from the first coupler to the second antenna port and outputting a second upstream signal of the second duplexing method input from the second antenna port to the sec

Abstract: The present invention is directed to a bi-directional optical monitor interconnect. The bi-directional monitor interconnect of the present invention includes an optical conductor with a first and second end. Disposed on the first end of the optical conductor is a first optical communication device and a first optical receiving device. Disposed on the second end of the optical conductor is a second optical communication device and a second optical receiving device. The first and second optical communication devices are capable of transmitting data over an optical connection. The first optical communication device is suitable for communicating via a first wavelength and the second optical communication device is capable of communicating over a second wavelength. The first receiving device is capable converting the second wavelength into electrical signals and the second receiving device is capable of converting the first wavelength into electrical signals.

Abstract: The present disclosure is directed to an optical transport system and device that conserves power, provides for efficient transport of photonic signals and is capable to accommodate a number of different nodes. The system and device are implemented with the major components at the nodes to provide easy maintenance. In a first aspect, the disclosure is directed to an optical transport system that provides for low power and efficient transport of photonic signals. The optical transport system can be implemented with a plurality of similar or identical network interface units that correspond with each node of the system. Also disclosed is an optical transport system architecture having an example architecture that includes a primary system and a secondary system, which is redundant to the primary system and is adapted to be operational when the primary system is inactive, or an example architecture that includes just a primary system.

Abstract: The subject invention pertains to a method and apparatus for multiplexing in optical fiber communications. The subject invention relates to a method and apparatus for spatial domain modulation in optical wavelengths. In a specific embodiment, the subject invention relates to a spatial domain multiplexer (SDM) for use with an optical fiber. Preferably, the input channels coupled into the fiber optic cable include collimated laser beams. The techniques of the subject invention can be utilized with single mode and multi mode waveguide structures, for example, single mode and multi mode optical fibers. The subject invention is applicable to step index optical fiber and to graded index optical fiber. Applications of the subject technology can include secure data links, for example, which can modulate data such that if the data is intercepted, the data cannot be interpreted. The subject methods and apparatus can also be used in conjunction with other multiplexing techniques such as time-domain multiplexing.

Abstract: A system is provided for implementing PCI Express protocol signals over an optical link. A transmission circuit is used to provide an electrical-to-optical conversion, a receiving circuit provides an optical-to-electrical conversion, and a sideband circuit is used to provide and receive control information.

Abstract: A small form factor pluggable (SFP) optical transceiver module and method for performing optical communications are provided. The SFP optical transceiver module has a housing to which a duplex receptacle is secured. The duplex receptacle has a C-shaped opening, the upper and lower portions of which are defined by upper and lower flexible retaining elements for receiving and retaining a duplex optical connector therein. An electrical assembly of the module is secured within the transceiver module housing. The electrical assembly comprises a PCB, the back end of which is configured as a plug end for removably plugging the PCB into a receptacle of an external communications management system.

Abstract: A method of transmitting data can include pre-emphasizing data for transmission by a transmitter over a transmission line based on an error feedback signal provided to the transmitter from a receiver of the pre-emphasized data.

Abstract: An apparatus and method are provided for combining, transmitting and receiving two or more high definition video control signals, namely, DDC and HDCP over a single bi-directional optical fiber or a duplex optical fiber, wherein a source and a sink are in communication with each other through the apparatus, and wherein the sink includes EDID and HDCP registers. A single transmitter module and receiver module pair are provided wherein the transmitter module includes replications of the sink EDID and HDCP registers, whereby any write request from the source to the sink is stored within the replicated EDID and HDCP registers so that any read request from the source to the sink can be answered immediately. Optional high definition video control signals may also be included in the system including Hot Plug, CEC, 5V and infrared.

Abstract: The present invention provides a bidirectional HDCP-based data transmission apparatus using an optical fiber which includes a core having a first facet and a second facet. The bidirectional HDCP-based data transmission apparatus includes a forward transmission module and a backward transmission module. The forward transmission module is used for emitting at least two forward light signals into a first end of a core of the optical fiber when being driven. Afterward, the at least two forward light signals are transmitted over the optical fiber immediately. The backward transmission module is used for receiving the at least two forward light signals transmitted over the optical fiber and emitting at least one backward light signal into a second end of the core of the optical fiber when being driven. Then, the backward light signal is immediately transmitted over the optical fiber, wherein the forward transmission module also receives the at least one backward light signal transmitted over the optical fiber.

Abstract: A transceiver system allows for simultaneous operation of transmit and receive modes, even in shared path configurations, by temporarily making the receiver insensitive to transmitter energy and by modifying standard readout technology to rapidly dissipate any transmitter energy deposited onto the receiver's detector elements. The entirely electronic technique alerts the receiver to the imminent emission of each transmitter pulse. This alert opens a gate voltage switch in the readout and prevents energy that is present on the detector from being passed to the readout integrator. As soon as the transmitter pulse has passed and any charges it generated on the detector have been dissipated, the switch is automatically closed and the receiver is again fully active. Since this on/off switching happens automatically and rapidly it can operate independently from, and have very little impact on the receiver. Furthermore, it levies absolutely no limitations whatsoever on the operation of the transmitter.

Abstract: A method of providing a visible light communication in a data link layer of a visible light communication system adopting an infrared communication link connection protocol includes: broadcasting a discovery exchange station identification (D-XID) frame; generating a visible frame to provide a visibility to a link for a specified waiting time period for responding to the broadcast D-XID frame; exchanging a set normal response mode (SNRM) frame and an unnumbered acknowledgement (UA) frame for requesting a link setting between the transmitting and receiving terminals; generating visible frames for a waiting time for receiving the SNRM frame and the UA frame; exchanging an information transfer frame (I-frame) and a receive ready (RR) frame, which is a response to the I-frame, between the transmitting and receiving terminals; and generating visible frames for a specified waiting period for receiving the I-frame and the RR frame.

Abstract: The present invention provides an optical transceiver that enables to reduce the crosstalk from the optical transmitter to the optical receiver. The regenerator of the optical transceiver includes two main amplifiers, a selector, a selector control, and a re-shaper for shaping the receiving signal selected by the selector. The first main amplifier provides a first amplifier and a delay circuit connected in upstream to the first amplifier. The second main amplifier provides a second amplifier and a delay circuit connected in downstream to the second amplifier. The selector selects, based on the phase difference between the receiving signal Rx and the transmitting signal Tx, the output from the first main amplifier or that from the second main amplifier.

Abstract: A method for sending and receiving asynchronous signals using optical techniques. The present invention implements open-drain circuit signaling utilizing a Finite State Machine and additional logic to reduce power requirements when transmitting asynchronous information via an optical transmission line. An embodiment exploits the 8 bit/10 bit encoder to detect errors and signal the beginning of valid data along the transmission line. The asynchronous signals may be transmitted during transitions in the Finite State Machine.

Abstract: A transmitting and receiving device, in which the received signal which is produced by the receiving device has only a small amount of crosstalk. This object is achieved by providing a transmitting and receiving device having a transmitting device for producing a transmission signal, a receiving device for producing a received signal, and a compensation device which is connected to the transmitting device and to the receiving device and which at least reduces any crosstalk which is produced by the transmitting device in the receiving device.

Abstract: An interface arrangement for opto-electronic data transfer which has an electrical plug connection part which includes at least one electrical contact used by a connected plug-in transceiver to provide information related to the data transfer rate at which the connected plug-in transceiver is able to transmit optical signals. An electrical control apparatus connected to this contact is used to set the data transfer rate of signals transferred from an electrical chip to a connected plug-in transceiver, the control apparatus taking several specified data transfer rates and setting that data transfer rate on the electrical chip which is the maximum at which a connected plug-in transceiver is able to transfer, provided that this data transfer rate is lower than the data transfer rate which has been set internally on the electrical chip. An opto-electronic transceiver which can be connected to an interface arrangement in plug-in fashion is also disclosed.

Abstract: Methods of providing duplex free-space optical, communication comprising receiving a time-shift keying (TSK) encoded signal and selectively re-modulating—and optionally retro-reflecting—received TSK pulses so as to transmit an on-off keying (OOK) signal. Related apparatus and signals are also provided.

Abstract: A method and device enables data communication via optical pulses from a light source of an electronic device. A data transfer interface is provided to support processing of selected data by a processor of the electronic device. The electronic device comprises an illumination light source, which is selectively utilized for illuminating a component in the electronic device and for transmitting data via optical pulses. An optical receiver also receives optically transmitted data. The transmission and receiving of the data is provided on a bidirectional duplex communication link created with a second optical receiver and an optical data transmission mechanism of a second electronic device.

Abstract: An apparatus is provided that is capable of achieving bidirectional, full-duplex communication with an optical transceiver. In some instances, the communication is achieved over a single electrical connection of the transceiver and via the use of a duplexing circuit on the transceiver and a complementary duplexing circuit on a distal circuit coupled to the transceiver via the single electrical connection. The techniques described may be used to modify existing optical transceivers to provide diagnostic or health information without interrupting normal transceiver operation.

Abstract: An apparatus and method for enabling cost-effective duplex communication by diplexing one of down stream signals for frequency up-conversion in a hybrid fiber-radio system includes diplexing an unmodulated mode signal among beating signals between a master laser and an injection-locked slave laser and using the diplexed signal for down-conversion in upstream transmission, thereby eliminating the need for expensive high-frequency local oscillators for frequency conversion. Higher radio frequency signals can be generated using beating between basic modes and satellite modes such as FWM conjugates of the master laser and slave laser. Cost-effective systems, stabilization of a light source and improved transmission performance may be achieved by using a diplexer instead of an expensive high-frequency local oscillator.

Abstract: Disclosed is an RoF system providing an HD wireless communication service.

Abstract: A bidirectional optical module having a light-emitting device 1 for emitting transmitting signal light therefrom, an optical fiber 8 which the transmitting signal light emitted from the light-emitting device is made to enter, a light-receiving device 9 which receiving signal light made to emerge from the optical fiber is made to enter, and a wavelength splitting filter 4; the transmitting signal light emitted from the light-emitting device being sent forward through the optical fiber, and the receiving signal light being received through the optical fiber. The bidirectional optical module has an optical device (optical isolator) consisting essentially of a reflection type polarizer 6 bonded to an end face of the optical fiber, a Faraday rotator 5 disposed integrally on the reflection type polarizer and an absorption type polarizer 3 disposed on an optical path extending between the light-emitting device and the wavelength splitting filter.

Abstract: Optical coupling device operates over a bidirectional data link between at least first and second communicators, each communicating data along a common wire of the data link. The device includes at least first and second optical couplers, each including a photon flux source and a photon flux detector. The photon flux source of the first and second optical couplers, respectively, is commanded by the first and second communicator, respectively. The photon flux detector of the first and second optical coupler, respectively, produces a signal on the data link at the first and second communicator, respectively, in response to the photon flux source of the second and first optical coupler, respectively, from the second and first communicator, respectively. An inhibitor inhibits the photon flux source of the second and first optical coupler, respectively, in response to an activation of the photon flux source of the first and second optical coupler, respectively.

Abstract: A duplexer for a communication device having a transmission unit, a reception unit and a shared antenna is disclosed. The duplexer comprises a first signal path between the transmission unit and the reception unit, the first signal path comprises a filter unit filtering the reception signal, the filtering unit provides a filtered signal to the reception unit. The duplexer further comprises a second signal path between the transmission unit and the reception unit. The second signal path comprises a cancellation unit which receives a sample of the transmission signal and produces a compensation signal. The injection of the compensation signal to the first signal path reduces the leakage signal, thereby producing a substantially leakage-free reception signal.

Abstract: An optical add/drop multiplexer (OADM) adapted to route optical signals having at least two different bit rates. The OADM has at least two sets of DWDM channels, e.g., with channels in a first set having a first bandwidth value suitable for the transmission of 10-Gb/s signals and channels in a second set having a second bandwidth value suitable for the transmission of 40-Gb/s signals. The first and second sets occupy two different spectral bands and the first set has two subsets of interleaved channels. In one embodiment, the OADM has first and second optical branches adapted to process optical signals corresponding to first and second groups of channels, respectively. The first group includes a first subset from the first set while the second group includes the second set and a second subset from the first set. Advantageously, OADMs of the invention may be used to create independent processing paths for different groups of channels. As a result, a communication system having those OADMs can be upgraded, e.g.

Abstract: A method, apparatus, and system for optical communications. An optical transmit signal is generated in response to an electrical transmit signal. The optical transmit signal is coupled into a single communication link for transmission there over. An optical receive signal is received from the single communication link, and in response an electrical receive signal is generated.

Abstract: A method and apparatus for sectorizing coverage of a cellular communications area includes providing a remote unit having microcell antenna units. Each microcell antenna unit is configured to cover a particular sector. The remote unit is connected to a sectorized base station unit which is connected to a mobile telecommunications switching office. Separate digitized streams representative of telephone signals received from the mobile telecommunications switching office are generated corresponding to the microcell antenna units and the separate digitized streams are multiplexed and transmitted to the remote unit. The remote unit demultiplexes the multiplexed digitized streams into the separate digitized streams corresponding to the microcell antenna units and the separate digitized streams are converted to RF signals for coverage of a particular sector by the corresponding microcell antenna unit.