Abstract: An output stage for WDM information transmission transmits a plurality of carrier waves modulated by an information signal and a filling lightwave. A first control circuit controls a desired power signal which determines the power of the filling light source so that the total power of carrier and filling lightwaves detected by a photodetector is held constant at a predetermined reference level. The filling light source is part of an assembly which is replaceably mounted at a first mounting location of the output stage. At a second mounting location of the output stage a second assembly comprising a second filling light source is mounted or adapted to be mounted. An auxiliary circuit is adapted to provide one of the two filling light sources with a continuously decreasing second desired power signal.

Abstract: Method and apparatus for operating for operating an optical network including a shared laser array are disclosed. An example apparatus includes include a first plurality of N lasers. Each laser of the first plurality of N lasers is configured to output a respective optical seed signal having a respective wavelength. The example apparatus further includes a first optical coupler coupled with the first plurality of N lasers. In the example embodiment, the first optical coupler is configured to multiplex the respective optical seed signals of the first plurality of N lasers onto a plurality of N optical fibers. In this example, each optical fiber of first plurality of N optical fibers transmits each of the respective optical seed signals produced by the plurality of N lasers to a respective distribution node for distribution to N respective optical network units, where the optical network units use the optical seed signals to seed respective optical transmitters located at the N optical network units.

Abstract: A wavelength-selective switch with a switch unit having a lens array, a first lens and a beam expander, and a branching unit having a second lens, a diffraction grating, a third lens and a mirror, in which the switch unit and the branching unit are accommodated in independent casings, and a confocal point of the light transmitted through the first lens and the light transmitted through the second lens are arranged on a connecting surface of the casing of the switch unit and the casing of the branching unit.

Abstract: Systems and methods provide for the addition of DWDM modules to CWDM systems in order to increase bandwidth over existing lines. This allows for the expansion of communications capacity without the need to replace existing CWDM systems. The DWDM modules can be transparently inserted into the CWDM systems by, in the CWDM system, reserving a channels for use by the DWDM. The DWDM system then occupies that channel with a scalable number of DWDM wavelength channels, for example four, eight, or sixteen. The DWDM systems can be used in both single and dual fiber systems as well as ring systems. Use of single fiber systems is obtained by implementing coupling devices, such as interleavers, passband filters, and circulators, that can used in pairs to couple bidirectional signals over a single fiber.

Abstract: An optical system having at least two waveguides that are deformable to provide adjustments to dispersion and path length.

Abstract: Methods and apparatus are described for distribution optical elements and compound collector lenses for a broadcast interconnect.

Abstract: Optical signals generated from customer premise equipment (CPE) at the edges of the metro domain networks are facilitated. The CPEs connect to extension terminals that transform the optical signal originating at the CPE into a format for long haul transmission. The optical signal then propagates to a primary terminal where the signal is multiplexed with other optical signals from other extension terminals. The multiplexed signals are then transmitted to a second primary terminal. The signal is then demultiplexed from other optical signals and transmitted to the proper extension terminal. At the extension terminal, the demultiplexed optical signal is transformed from its LH format back into a format suitable for inter-connection to a CPE. The signal undergoes optical-to-electrical conversion only at the extension terminals or end points, which can be located at lessee's facility. The only equipment located in lessor's facility is the primary terminal containing line amplifiers and add/drop nodes.

Abstract: An apparatus comprising a wavelength division multiplexing (WDM) coupler configured to couple an optical line terminal (OLT) comprising a transmitter and a receiver, wherein the WDM coupler is coupled to the transmitter via a first fiber and to the receiver via a second fiber. An apparatus comprising a WDM coupler for a passive optical network (PON) comprising a plurality of filters and a plurality of ports, wherein the WDM coupler comprises fewer filters than ports. A method comprising receiving a downstream optical signal intended for an optical network terminal (ONT) via a first fiber, and transmitting an upstream optical signal received from the ONT via a second fiber.

Abstract: An optical signal processing device for shaping a waveform of an optical signal, including: an intensity inversion wavelength converter configured to generate an intensity-modulated optical signal of a second wavelength obtained by inverting a signal intensity of an input intensity-modulated optical signal of a first wavelength; an optical coupler configured to multiplex the intensity-modulated optical signal of the first wavelength and the intensity-modulated optical signal of the second wavelength at a timing at which signal intensities of those signals become opposite; and an optical limiter configured to input coupled light output from the optical coupler, and suppress gain as power of the coupled light becomes higher.

Abstract: A passive optical network includes: a central office for generating multiplexed downstream optical signals and receiving an upstream optical signal; a plurality of optical network units for receiving a corresponding downstream optical signal and generating subcarrier channels carrying electrical data of an assigned frequency; and a remote node for photoelectrically converting the channels into electrical data, electro-optically converting the electrical data into at least one upstream optical signal.

Abstract: A micro-optic dual beam-splitter assembly comprises at least two beam-splitter optical filters and at least one photoreceptor. Each of the beam-splitter optical filters comprises an optical substrate having at least a coated or uncoated optical tap surface and a filter surface carrying a thin-film optical filter. The thin-film optical filters are substantially normal to the optical path from an optical signal source. Each of the optical tap surfaces is operative as an optical beam splitter to tap off an optical tap signal. The one or more photoreceptors are arranged to receive both or at least one of the optical tap signals. The tap signals comprise a portion of the optical signals passed along the optical path to the optical filter chips. The filter chips are cooperatively transmissive to an optical signal output port of a selected set of wavelengths received from the optical signal source along the optical path, and are reflective of other wavelengths.

Abstract: Multiplex-demultiplex (mux/demux) “groups” multiplex and demultiplex a predetermined maximum number of optical wavelengths. A method for assigning wavelengths of fiber links and mux/demux groups to given traffic (or traffic segments) in an optical communications network, minimizes over all terminals a total number of mux/demux groups required. The method (FIG. 5) involves (510) sorting the terminals in order of size of load. Further, for each traffic segment between pairs of first and second terminals, the method involves (516) assigning a smallest wavelength that is available between the first and second terminals and that is available on the segment path between the terminals; and in the terminals, (518) deploying mux/demux groups supporting the assigned wavelengths. A modified method (FIGS. 6A, 6B), as well as a method for dynamically assigning and deploying newly arriving traffic segments (FIG. 7), are also provided.

Abstract: An optical ring network architecture including a number (N) of multi-add/drop filters, such as filters formed using symmetrical pairs of frequency routers. Each multi-add/drop filter is coupled to two other multi-add/drop filters using N?2 transmission media, such as optical fibers, to form a ring. The network also includes a number (N) of terminal stations associated with the multi-add/drop filters. A terminal station (p) is coupled with, and receives information from, its associated multi-add/drop filter (p) through a single optical fiber. In addition, the terminal station p is coupled with, and transmits information in a first direction around the ring to, a multi-add/drop filter p+1 through a single optical fiber. Communications from terminal station p to each other terminal station in the first direction are assigned one of N?1 wavelengths such that no two wavelengths on a given optical fiber are associated with communications between terminal stations in the same direction.

Abstract: The present invention relates to an installation for conveying electrical signals carried by a first triaxial cable (1) to a second triaxial cable (18). It comprises: a first interface (15) between the first triaxial cable (1) and a fibre optic cable (9) and a second interface (16) between the fibre optic (9) cable and the second triaxial cable (18). A television camera (17) is connected to a remote camera control unit (14) via this installation. The first triaxial cable (1) connects CCU (14) with the interface (15). The interface (15) comprises an adapter converting electrical signals, conveyed by the triaxial cable (1), to optical signals. The fibre optic cable (9) transmits optical signals to the second interface (16). The interface (16) comprises an adapter converting optical signals to electrical signals. The second triaxial cable (18) transmits the electrical signals to the television camera (17). A mirror image of the adapters allows transmitting electrical signals from the camera (17) to the CCU (14).

Abstract: An optical hybrid circuit includes a MMI coupler including a pair of input channels provided at positions symmetrical with respect to a center position in a widthwise direction thereof, a pair of first output channels outputting a pair of first optical signals having an in-phase relationship, and a pair of second output channels neighboring with each other outputting a pair of second optical signals having an in-phase relationship. The MMI coupler converts QPSK signal light or DQPSK signal light into the pair of first optical signals and the pair of second optical signals having an in-phase relationship. The optical hybrid circuit includes a 2:2 optical coupler connected to the first or the second output channels. The 2:2 optical coupler converts the pair of first optical signals or the pair of second optical signals into a pair of third optical signals having a quadrature phase relationship with the pair of first or second optical signals.

Abstract: A chirp switching circuit comprises a Mach-Zehnder modulator having a Y-branched part for branching an incoming optical signal into first and second optical signals and an X-branched part merging the first and second optical signals with each other, the Mach-Zehnder modulator causing phase modulation in the first and second optical signals by a modulation signal, and a directional coupling optical switch that switches first and second optical output signals output from the X-branched part of the Mach-Zehnder modulator by merging the first and second output optical signals in response to a chirp switching control signal.

Abstract: Systems and methods for encoding information in the topology of superpositions of helical modes of light, and retrieving information from each of the superposed modes individually or in parallel. These methods can be applied to beams of light that already carry information through other channels, such as amplitude modulation or wavelength dispersive multiplexing, enabling such beams to be multiplexed and subsequently demultiplexed. The systems and methods of the present invention increase the number of data channels carried by a factor of the number of superposed helical modes.

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: In the manufacture and application of a PLC-ECL type wavelength tunable light source, provided is a wavelength tunable mechanism with improved performance and stability, a light source with improved packaging performance and mass productivity, and a light source applied to a WDM-PON with initialization and stabilization functions. The wavelength tunable light source having a PLC (planar lightwave circuit)-ECL (external cavity laser) structure includes a first housing in which a semiconductor optical gain medium is mounted, a second housing in which a PLC device is mounted, and a third housing in which an optical fiber is mounted. The first, second, and third housings make an optical axis alignment through an optical coupling lens and combined in a laser welding method.

Abstract: A lock detection apparatus detecting lock of an optical phase-locked loop apparatus including a first phase detector comparing phases of an input light signal and a beat light signal to output a first phase comparison signal, a loop filter forming the first phase comparison signal, and an optical voltage controlled oscillator outputting the beat light signal based on the formed first phase comparison signal. The lock detection apparatus includes: a phase shifter shifting the phase of the beat light signal; and a second phase detector comparing the phases of the input light signal and the phase-shifted beat light signal to output a second phase comparison signal, wherein the phase shifter shifts a quantity of the phase so that the phase comparison signal may not be 0 when the phases of the two light signals compared by the second phase detector synchronize with each other to the beat light signal.

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: An apparatus comprising a mode coupler configured to couple a plurality optical signals into a plurality of modes, and a receiver coupled to the mode coupler and configured to detect the modes to obtain the optical signals, wherein the optical signals are coupled from single mode fibers. Also disclosed is an apparatus comprising a plurality of single mode waveguides configured to transport a plurality of single mode signals, and a detector coupled to the single mode waveguides and configured to detect the single mode signals, wherein the single mode signals are substantially coupled without loss from the single mode waveguides to the detector. Also disclosed is a method comprising receiving a plurality of single mode optical channels, coupling the single mode optical channels into a multimode channel, and detecting the optical modes corresponding to the channels in the multimode channel.

Abstract: The optical node connects N networks to each other (where N is an integer larger than one). Each of the N networks respectively includes a first transmission path and a second transmission path. The optical node includes a switching unit that connects the first transmission path of one network of the N networks to other (N?1) networks; a failure detector that detects failure in the first transmission path of the network; and a control unit that causes the switching unit to connect the second transmission path of the network to the other (N?1) networks when the failure is detected.

Abstract: An optical connecting apparatus has a light source outputting an optical signal indicating a plurality of wavelengths which correspond to a plurality of transmission channels, an optical transmit section and an optical receive section being mounted with integrated circuits and being connected to each other through an optical line of a single system, and a signal conversion section being inlet in the optical line and converting a phase modulated signal into an intensity modulated signal.

Abstract: An optical subassembly manufacturing method includes forming connecting electrodes and a piece of high-melting-point glass on a wiring substrate; positioning on and connecting to the connecting electrodes, an optoelectronic converting element; disposing on the piece of high-melting-point glass, a piece of low-melting-point glass having a melting point lower than the piece of high-melting-point glass; and fixing to the piece of low-melting-point glass, a protruding portion of a lens member further having a lens portion. The protruding portion has a shape matching that of the piece of high-melting-point glass, and relative positions of the protruding portion and the optical axis of the lens portion are determined to correspond to relative positions of the connecting electrodes and the piece of high-melting-point glass. The fixing includes fixing the protruding portion of the lens member to the piece of high-melting-point glass via surface tension generated by melting the piece of low-melting-point glass.

Abstract: A relay node used in a WDM optical network is disclosed. The relay node includes: a high-speed side port configured to send and receive a high-speed signal; a low-speed side port configured to send and receive a low-speed signal; a unit configured to generates a checking message for requesting another node to report constraint information of a low-speed side port of the another node, wherein the constraint information relates to adding an optical signal from the low-speed side port to a high-speed side port of the another node or dropping an optical signal from the high-speed side port to the low-speed side port of the another node; a unit configured to generate a response message including the constraint information of the own node in response to receiving the checking message sent from the another node; and a storing unit configured to store at least the constraint information of the another node.

Abstract: A ring optical transmission network access node (ANi) comprises: two identical band splitters (BSa, BSb), each provided with homologous first, second and third ports (Ba, BWa, BPa; Bb, BWb, BPb), a first coupler (CW) coupling the second port (BWb) of the second splitter (BSb), on the one hand, to the second port (BWa) of the first splitter (BSa) via a first channel and, on the other hand, to an access point (A2) via a second channel, a second coupler (CP) coupling the third port (BPa) of the first splitter (BSa), on the one hand, to the third port (BPb) of the second band splitter (BSb) via a first channel and, on the other hand, to another access point (A1) via a second channel. Such nodes enable the implementation of a passive ring network comprising only one fiber and in which the coupling ratios of the couplers (CW, CP) are optimized for two opposite traffic propagation directions. Application in particular to optical fiber metropolitan access networks, with broken fiber protection device.

Abstract: Optical communication networks often incorporate fiber rings or fiber mesh topologies for interconnecting its nodes. Both of these topologies can contain closed optical loops at one or more wavelengths within the optical spectrum. In amplified optical systems, the inherent loss of these optical loops is counteracted by the amplifier gain. Thus, the optical loop may have a net loss that is too low to prevent excessive noise buildup resulting in a lasing fiber loop. The noise that builds up within such amplified systems is dominated by the Amplified Spontaneous Emission (ASE) noise resulting in ASE loops. Such loops can have a serious impact on all wavelengths carried by the fiber and lead to a partial or complete loss of end to end communication due to a severe degradation in signal to noise ratio. This invention provides an effective method and system for avoiding ASE loops in optical communication networks.

Abstract: The invention is directed to a pluggable module and mounting socket for use in an optical network terminal (ONT). In particular, the mounting socket accepts a pluggable module comprising either a dual-section triplexer card or a single-section diplexer card, thereby allowing a vendor to selectively change the type of PON transport by simply changing the diplexer/triplexer pluggable module to support either diplexer or triplexer applications. The ability to configure the ONT by swapping out the pluggable diplexer/triplexer module eliminates the need for a manufacturer to maintain two different versions of the ONT, i.e., with or without video.

Abstract: The present invention provides an apparatus for multiplexing a plurality of light waves with different wavelengths. The apparatus includes a laser sub-assembly, a multiplexer sub-assembly, and a receptacle sub-assembly. The laser sub-assembly includes a plurality of lasers for radiating a plurality of light waves of different wavelengths. The plurality of light waves are multiplexed in the multiplexer sub-assembly. The multiplexed light waves are coupled to an optical fiber by the receptacle sub-assembly.

Abstract: An optical modulating circuit realizing a PPM is constituted by circuit parts having a frequency band equal to a data rate to provide a technique which increase the data rate. A first light source generates a first single wavelength signal serving as a continuous light having a first wavelength ?1 as a wavelength of a carrier wave. A second light source generates a second single wavelength signal serving as a continuous light having a second wavelength ?2 different from ?1 as a wavelength of a carrier wave. For the first single wavelength signal and the second single wavelength signal, according to a transmission electric signal having information 0 or 1, an optical switch outputs a first single wavelength signal as an input optical signal when the information is 0. On the other hand, when the information is 1, the optical switch outputs the second single wavelength signal as an input optical signal.

Abstract: A light-emitting device includes a plurality of ultra-small resonant structures, each of said structures constructed and adapted to emit electromagnetic radiation (EMR) at a particular wavelength when a beam of charged particles is passed nearby. A combiner mechanism constructed and adapted to combine data from a data source with the EMR emitted by at least one of the ultra-small resonant structures.

Abstract: This invention provides a system that combines a wavelength multiplexer with an FM discriminator for chirp reduction and wavelength locker in a filter to produce a wavelength division multiplexed signal with reduced chirp. A partially frequency modulation laser signal is converted into a substantially amplitude modulation laser signal. This conversion increases the extinction ratio of the input signal and further reduces the chirp. A wavelength division multiplexing (WDM) method is used for transmitting high capacity information through fiber optics systems where digital information is carried on separate wavelengths through the same fiber. Separate transmitters normally generate their respective signals that are transmitted at different wavelengths. These signals are then combined using a wavelength multiplexer to transmit the high capacity information through the fiber optic system.

Abstract: An integrated single-fiber multi-directional transceiver such as a diplexer or triplexer for FTTH applications comprises at least a laser for transmitting a first signal at a first wavelength, a photodetector for receiving a second signal at a second wavelength, and a 2×2 optical coupler. The 2×2 optical coupler has four ports, of which port 1 connects to a fiber through an input/output waveguide, port 2 leads to the photodetector through another waveguide, port 3 and port 4 are connected with the gain waveguide and are placed inside the laser cavity. Light emitted by the gain waveguide inside the laser cavity at port 3 of the coupler is partially coupled to port 4 as a feedback for the laser and partially coupled to port 1 which couples to the optical fiber to transmit the first signal. On the other hand, the second signal at the second wavelength that is launched into the coupler from the input/output waveguide at port 1 is entirely coupled to port 2 that leads to the photodetector.

Abstract: Provided is a fiber ring laser capable of obtaining a back-up laser light and standard light having a wavelength continuously tuned in a single mode with equal spacing of 12.5 GHz, 25 GHz, 50 GHz or 100 GHz recommended by ITU-T Recommendation G. 692 & G. 694.1 in a C-band and an L-band using a fiber tunable etalon filter, an air gap etalon filter and a saturable absorber in an optical fiber laser resonator having a serial ring shape using a C-band optical amplifier and an L-band optical amplifier. The fiber ring laser can generate laser light having a wavelength tuned by more than 70 nm, excellent output power flatness and a source spontaneous emission ratio of more than 70 dB in 361 channels with equal spacing of 25 GHz by applying a bias voltage to a voltage-operated piezoelectric element of a tunable etalon filter. A single longitudinal mode operation of the fiber ring laser can be obtained by using a saturable absorber serving as a narrow-bandwidth filter.

Abstract: A method for token-controlled data transmission includes receiving a token including transmission data specifying one of a plurality of data channels and a time window. A burst blocker is configured, based at least in part on the transmission data, for the selective communication of the specified data channel on an optical transmission medium having the plurality of data channels. The selective configuration of the burst blocker includes splitting the specified data channel from the plurality of data channels, configuring the burst blocker in a first configuration during a time other than the time window to rejoin the specified data channel with the plurality of data channels for transmission of the plurality of data channels toward a destination node, and configuring the burst blocker in a second configuration during the time window to block the specified data channel to prevent the transmission of the specified data channel.

Abstract: Heretofore, it was necessary to individually locate an optical switch, an optical switch control circuit, and the like, before and after an optical transceiver that performs optical protection. As a result, costs and the space for implementation increase, and a delay in services is also caused, which were the problems. For the purpose of solving the above problems, the present invention provides a simple optical protection method used in an optical add-drop multiplexer. Add switches 105-1 through 105-N and drop switches 103-1 through 103-N for optical signals corresponding to each wavelength in an optical add-drop multiplexer 100 are made controllable independently of one another. Add switches and drop switches of the active-side and backup-side optical add-drop multiplexers are switched by optical switch control circuits 106-1 through 106-N respectively to make a detour around a failure so that the optical protection is achieved.

Abstract: A WDM optical system includes first and second WDM's including an optical link therebetween. Each WDM includes circuitry for linking multiplexer and demultiplexer circuitry to a plurality of modular elements. The modular elements include a first set of modules for converting between native protocol media signals and common format signals. A second set of modules converts between the common format signals and optical signals at separate wavelengths for communication with the multiplexers and demultiplexers. A dual path transmit and receive optical link is provided between near and far end WDM's.

Abstract: Transceivers, networks, and methods for providing data communication to electrical devices in a vehicle, and a vehicle comprising the transceiver and network. A transceiver of the network can include a receive optical subassembly including an opto-electronic transducer configured to receive a first incoming optical signal from an optical fiber having a silica based core. Signal extraction circuitry is configured to extract data intended for an electrical device from of the incoming optical signal and provide the extracted data to the electrical device, and a transmit optical subassembly comprising a laser, such as a VCSEL, configured to transmit an outgoing optical signal to a second optical fiber having a silica based core.

Abstract: A distribution node for an optical network is provided that includes an integrated filter module comprising a first thin-film and a second thin-film coupled to a common substrate and operable to receive a first downstream signal at the substrate comprising at least traffic in a first wavelength and a second wavelength, transmit the traffic in the first wavelength from the first thin-film to a first plurality of downstream terminals, reflect the traffic in the second wavelength to the second thin-film, and transmit at least the traffic in the second wavelength from the second thin-film to a second plurality of downstream terminals. A traffic distributor is operable to receive a second downstream signal comprising at least traffic in a third wavelength and forward the traffic in the third wavelength to the common substrate for distribution to the first plurality and second plurality of downstream terminals.

Abstract: A digital optical network (DON) is a new approach to low-cost, more compact optical transmitter modules and optical receiver modules for deployment in optical transport networks (OTNs). One important aspect of a digital optical network is the incorporation in these modules of transmitter photonic integrated circuit (TxPIC) chips and receiver photonic integrated circuit (TxPIC) chips in lieu of discrete modulated sources and detector sources with discrete multiplexers or demultiplexers.

Abstract: Provided is a multimode optical transmission system capable of reducing an influence of multimode dispersion occurring when an optical signal is transmitted in multimode. Light sources (101 to 10m) respectively convert inputted electrical signals into a plurality of optical signals respectively having different wavelengths, and respectively output the plurality of optical signals. A wavelength multiplexing section (200) performs wavelength multiplexing of the plurality of optical signals outputted from the light sources (101 to 10m), and outputs a resultant signal as a wavelength multiplexed signal. A multimode optical transmission path (300) optically transmits the wavelength multiplexed signal in multimode. A mode processing section (400) extracts, from the wavelength multiplexed signal transmitted through the multimode optical transmission path (300), a plurality of optical signals each being in a mode having a particular wavelength and a particular propagation constant.

Abstract: An optical transmitter for coupling and wavelength-multiplexing optical signals with a different wavelength has 3 or more light sources for emitting parallel optical signals with a different wavelength, and 2 kinds of optical components with a different optical signal reflectance arranged in an optical path of each light source for coupling into one the optical signals emitted from the light sources respectively. The reflectance or transmittance of each of the 2 kinds of optical components is set so that each optical signal has the same optical signal power when reflected off or transmitted through the optical components for being coupled together and output from the optical transmitter.

Abstract: One of two optical fibers connecting communication stations is used for transmitting multiple wavelength light supplied from a multiple wavelength light source supply apparatus, and the other for a bidirectional communication using optical signals of respective wavelengths generated from the multiple wavelength light. Alternatively, a transmission of multiple wavelength light and a bidirectional communication using the optical signals are enabled by only one optical fiber.

Abstract: The present invention relates to a wavelength-tunable light source whose output wavelength can be externally controlled and a wavelength-division multiplexed transmission system using the source. A wavelength-tunable light source in accordance with the present invention is constituted to be able to vary the output wavelength of a Fabry-Perot laser diode, that is wavelength-locked to an injected light, by controlling the wavelength of the injected light. A wavelength-tunable light source in accordance with the present invention provides comparatively large output power and excellent economic features. The present invention also presents a wavelength-division multiplexed transmission system using, the wavelength-tunable light source.

Abstract: In a system where a quantum channel and a classical channel are multiplexed on a single optical transmission line and information is transmitted from a transmitter to a receiver through the quantum channel, the classical channel is inhibited from affecting the quantum channel. To this end, the transmission characteristics of a transmitter-side wavelength multiplexer/demultiplexer for the classical channel, the transmission characteristics of a receiver-side wavelength multiplexer/demultiplexer for the quantum channel, and the optical power of a light source for the classical channel are designed so that crosstalk light due to spontaneous emission light and crosstalk light due to nonlinear optical effects can be suppressed, and the classical channel does not affect the quantum channel.

Abstract: A refrigerating apparatus for a refrigerator has an electrical voltage supply and an electrical interface for connection with components of the refrigerator with the interface having a galvanic isolation between an input arrangement connected with the refrigerating apparatus and an output arrangement connected with at least one component of the refrigerator.

Abstract: An wave division multiplexed (WDM) optical transmitter is disclosed including a directly modulated laser array and a planar lightwave chip (PLC) having a plurality of OSRs that receive outputs of the laser array and increase the extinction ratio of the received light. An optical multiplexer receives the outputs of the OSRs and couples them to a single output port. The multiplexer has transmission peaks through its ports each having a 0.5 dB bandwidth including the frequency of a laser in the array. The optical multiplexer may be embodied as cascaded Mach-Zehnder interferometers or ring resonators.

Abstract: A 1550 nm DWDM optical communications network has a 1300 nm remote node added to which a small number of channels can be added or dropped. The additional node includes dual wavelength couplers to enable 1300 nm wavelength signals to be added or dropped. The 1300 nm signals are demultiplexed using a WDM filter and connected into the transponders of the 1550 nm nodes for transportation around the node. Signals for the remote network are converted to 1300 nm signals at the 1550 nm node transponders and multiplexed onto the network to be dropped to the network node transponder.

Abstract: An addressing method of quantum network and a quantum network router are disclosed. There are at least three nodes in the network. The method comprises steps of: appointing an address serial number for every node; sending photon signals with different wavelength from one node to other nodes, wherein the signal source wavelength and node address are regarded as an addressing badge; determining, by every node, the source of signal according to the addressing badge of received photon signals. Quantum network router comprises a photon signal allocator including N sets of optical components, one end of every optical component is mix-wavelength interface, and the other end includes separate wavelength interfaces; an external interface comprising mix-wavelength interfaces of optical components, separate wavelength interfaces of different optical components, which transmit the same wavelength signals, connect one to one.