Abstract: Implementations of the present principles include methods, systems and apparatuses for transmitting data through a sub-carrier multiplexing and orthogonal frequency-division multiple access passive optical network. In accordance with aspects of the present principles, a plurality of optical network units are assigned electrical carrier frequency bandwidths that are narrower than a system capacity bandwidth. Modulation of optical waves transmitted between an optical line terminal and each optical network unit is conducted on different orthogonal sub-carrier frequencies within the assigned bandwidths such that sampling of said orthogonal sub-carrier frequencies is limited to the assigned electrical carrier frequency bandwidths. The waves are thereafter received and demodulated for the extraction of data.

Abstract: A system includes an optical line terminal (OLT) that includes an OLT transmitter. The OLT transmitter includes one or more fixed wavelength optical sources that generate an optical signal at a first wavelength, and an optical waveguide that transmits the optical signal at the first wavelength in an optical network.

Abstract: To achieve a station-side apparatus of a wavelength multiplexing PON system, which is capable of saving the wavelength resource through automatically carrying out allotment of the wavelength and the network address to reduce the complicated work for the setting, and through dynamically allotting the wavelength without fixing it in advance. It is a station-side apparatus (OLT) of a wavelength multiplexing PON system that comprises a plurality of in-home apparatuses (ONUs). The station-side apparatus is connected to the in-home apparatuses via transmission paths including an optical multiplexing distributor, and executes allotment of the wavelength in response to wavelength allotment requests from the in-home apparatuses. The station-side apparatus comprises a wavelength/network address allotting device that is provided with a DHCP server in advance, which dynamically allots wavelength and network address to the in-home apparatus in response to the wavelength allotment request from the in-home apparatus.

Abstract: To provide an extra wide bandwidth communication using standard channels, multiple non-overlapping channels can be used. To provide a 40 MHz communication, two non-overlapping 20 MHz channels, i.e. a control channel and an extension channel, can be used to provide an effective 40 MHz channel. Advantageously, a wireless device can dynamically detect 20/40 MHz signals on a packet-by-packet basis, thereby facilitating commercially viable 40 MHz communication. The wireless device can monitor traffic on the extension channel to facilitate accurate 20/40 MHz decision making. Protection, e.g. legacy preambles and RTS/CTS headers, can be provided on the control and extension channels.

Abstract: After implementing a scrambler upon an electric signal of digital signals to be transmitted to a user terminal, this electric signal is converted into a digital optical signal, and an analog optical signal and this digital optical signal are multiplexed by wavelength division multiplexing, thereby reducing influence of cross-talk interference that is exerted on the analog optical signal by the digital optical signal.

Abstract: A model is provided for optimizing an optical network wherein single links carry multiple signals by using multiple color channels. The routes in the optimized network minimize mid-route color changeovers, reducing the number of nodes requiring optical-electric-optical signal conversion. In the model, the minimized objective function includes terms representing total color miles, terms penalizing changeovers, and terms representing total nodes passed by routes.

Abstract: A device determines a bandwidth demand for traffic provided between a line terminal (LT) and multiple optical network terminals (ONTs), and dynamically tunes, based on the determined bandwidth demand, one or more tunable filters provided in the LT and the multiple ONTs to one of balance the traffic, protect the traffic, or increase available bandwidth for the traffic.

Abstract: A wavelength division multiplexing based passive optical network is disclosed. The network includes an optical line terminal; a power optical splitter connecting to the optical line terminal by an optical fiber; and several optical network units. Each of the optical network units connects to the power optical splitter by each of other optical fibers by a random process.

Abstract: In a PON system with WDM, at the time of initial setting, each ONU negotiates with an OLT, and automatically acquires a wavelength which can be used by the ONU. One wavelength for negotiation of assigned wavelength is fixed as a default, and a newly connected ONU first uses the wavelength. The OLT 200 includes a plurality of light sources for downstream communication. The ONU 300 includes a wavelength variable filter selectively receiving one of wavelengths of downstream communication, and a wavelength variable light source selectively emitting light of one of plural wavelengths for upstream communication. The ONU 300 uses a transmission wavelength (for example, ?u32) for negotiation and transmits a wavelength assignment request 1000 to the OLT 200. The OLT 200 selects a wavelength ?u1 to be assigned from unused wavelengths, and transmits wavelength information to the ONU 300. The OLT 200 and the ONU 300 communicates using the notified wavelengths.

Abstract: A wavelength division multiplexing passive optical network system is provided. A central office generates a multi-mode light having a mode interval equal to a period interval of a multiplexing filter of the remote node and the multi-mode light is used to control a wavelength of an uplink transmission optical signal of the optical network unit. A remote node multiplexes the multi-mode light with the multiplexing filter to transmit the multiplexed multi-mode light to the optical network unit and demultiplexes the uplink transmission optical signal to transmit the demultiplexed uplink transmission optical signal to the central office. An the optical network unit generates the uplink transmission optical signal by modulating a data signal with a Fabry-Perot laser which uses the multiplexed multi-mode light as an injection optical source. Accordingly, it is possible to control a wavelength of a transmitter of the optical network unit by using the injection optical source generated by the central office.

Abstract: A radio-over-fiber (RoF) wireless picocellular system adapted to form an array of substantially non-overlapping individual picocells by operating adjacent picocells at different frequencies is operated to form one or more combined picocells. The combined picocells are formed from two or more neighboring picocells by the central head-end station operating neighboring picocells at a common frequency. Communication between the central head-end station and a client device residing within a combined picocell is enhanced by the availability of two or more transponder antenna systems. Thus, enhanced communication techniques such as antenna diversity, phased-array antenna networks and multiple-input/multiple-output (MIMO) methods can be implemented to provide the system with enhanced performance capability. These techniques are preferably implemented at the central head-end station to avoid having to make substantial changes to the wireless picocellular system infrastructure.

Abstract: Disclosed is a distributed controlled passive optical network system and bandwidth control method thereof. The system comprises an optical line terminal (OLT), plural optical network units (ONUs) and a splitter with combiner. Each ONU has a first Tx/Rx for respectively transmitting and receiving data packets on an upstream data channel and a downstream data channel, and a second Tx/Rx for transmitting and receiving control signals/commands on a control channel. Upstream data of each ONU is carried by the upstream data channel and sent to the OLT through the splitter with combiner. Downstream data of the OLT is carried by the downstream data channel and sent to corresponding ONUs through the splitter with combiner. With the control signals/commands carried by the control channel, the required information of network status among the ONUs is provided.

Abstract: A system is provided for intercepting signals transmitted between a target served by a fiber optic network and a subscriber. A network is described having a phone switch at a central office configured to receive signals for transmission to and from a target, such as the target of a criminal investigation. A signal received at the central office is assigned to an analog circuit, and a monitoring device configured to intercept and monitor the signal is installed along the analog circuit at a location that allows the monitoring of communications without notifying the target that he is under surveillance. After the signal has been monitored, it is converted to a digital signal for transmission. A method is also provided for intercepting a signal transmitted between the target served by a fiber optic network and a subscriber, such that a monitoring device may be installed without alerting the target.

Abstract: The present disclosure provides a passive optical network (PON) system and a method for protecting the service of the system for service recovery and fault locating in case of a failure of the network, wherein the PON system comprises an optical line terminal (OLT), an optical distribution network (ODN) and an optical network terminal (ONT) equipment protection group comprising a plurality of ONT equipment groups, each of which is connected to at least one of other ONT equipment groups within the ONT equipment protection group for the mutual protection relationship. The PON system of the present disclosure does not require equipment and link redundancy for backup, contributes to reduced cost and improved utilization of resources, and provides a means for diagnosing any faults of the links and equipment in the network.

Abstract: The present research relates to s a transmission frame structure supporting a data service and a circuit service of diverse bands in a Synchronous Optical Network (SONET)/Synchronous Digital Hierarchy (SDH) network. This research provides a transmission frame structure including a sync period, an async period, and a control period and provides a multiplexing apparatus that can add or extract a fixed length frame in the synch period of the transmission frame and add or extract a variable length frame in the asynch period, and a method for transmitting the transmission frame. The transmission frame structure includes a sync period for transmitting a fixed length frame; an async period for transmitting a variable length frame; and a control period for transmitting a control frame storing information for discriminating between the sync period and the async period. The technology of this research can be applied to a synchronous optical network system.

Abstract: A DWDM optical system in a first embodiment includes a plurality of scramblers on the transmit side and a plurality of corresponding de-scramblers on the receiver side of the DWDM system. Each scrambler includes an input for an encryption key with the corresponding de-scrambler including an input for the same encryption key. In accordance with the pseudorandom encryption key, input data channels are scrambled onto output optical channels to provide data security across the optical path. With a suitable algorithm, this technique can provide very strong data confidentiality. The strength of the technique of the embodiments of the invention resides in the scrambling algorithm that is used to scramble the data over the optical carriers. Preferably the scrambling algorithm is very unpredictable and does not repeat for a very long time.

Abstract: A method and system for ensuring confidentiality of signal transmission in a point-to-multipoint data transmission network like Ethernet passive optical network, including at least one hub, at least one transmission medium and at least one station connected to the hub via the transmission medium. When an upstream signal is transmitted from a first station, the upstream signal is reflected by at least one disturbing reflector for producing a disturbing reflection. The disturbing reflection combines with a second reflection of the upstream signal and renders the second reflection undecodable by a second station.

Abstract: The present invention discloses a method for controlling multicast flow in passive optical network includes: receiving multicast data from the optical line terminal, determining whether the received multicast data satisfies a multicast right control condition, transmitting the multicast data to the user side if the received multicast data satisfies the multicast right control condition, or discarding the multicast data if the received multicast data does not satisfy the multicast right control condition. The present invention also discloses an optical network terminal, an optical line terminal, and a system consisting of an optical network terminal and an optical line terminal and an optical distribute network, which implement the above mentioned method. The present invention could prevent the optical network terminal from receiving illegal multicast data and enhance the multicast security of the whole passive optical network system.

Abstract: A method and apparatus is provided for transmitting a WDM optical signal. The method begins by modulating a plurality of optical channels that are each located at a different wavelength from one another with a respective one of a plurality of information-bearing electrical signals The channel spacings between adjacent ones of the plurality of optical channels are selected such that the optical channels give rise to selected FWM terms that lie outside a channel bandwidth of the optical channels. Each of the modulated optical channels is multiplexed to form a WDM optical signal. The WDM optical signal is then forwarded onto an optical transmission path.

Abstract: An optical repeater device of the present invention comprises: a preamble compensating circuit 53, for taking out a normal data signal from burst signals propagating through a communication transmission path, and for adding a preamble signal before and/or after the data signal. Furthermore, the preamble compensating circuit 53 comprises: a detector circuit 53a, for inputting the burst signal, and for outputting only the normal data signal; a buffer circuit 53b, for storing the data signal output from the detector circuit 53a, and for outputting thereof; a preamble signal generation circuit 53d, for outputting at least one type of the preamble signal; and an data output select circuit 53e, for outputting the data signal at the time of the data signal input from the buffer circuit 53b, and for outputting the preamble signal from the preamble signal generation circuit 53d at any other time thereof.

Abstract: An optical system with a first and second network tiers. The first network tier includes a plurality of major nodes optically interconnected by at least one transmission path. The second network tier includes a plurality of minor nodes disposed along the transmission path and the minor nodes are connected to at least one of the major nodes. The minor node is configured to transmit all traffic to an adjacent major node, and the major nodes are configured to transmit to and receive information from other major nodes and minor nodes on transmission paths connected to the major node.

Abstract: A device including a semiconductor laser device having a semiconductor laser chip, and a molded resin having a light diffusion capability. The semiconductor laser chip is covered with the molded resin.

Abstract: In a WDM type PON system, each ONU comprises an optical transmitter capable to transmit optical signals with variable wavelengths, an optical signal receiving filter variable its receiving wavelength, and a control unit. An OLT selects in response to a wavelength allocation request from each ONU, a transmitting wavelength and a receiving wavelength out of currently free wavelengths and allocates these wavelengths to the requester ONT. The control unit of the ONU switches the transmitting wavelength of the optical transmitter and the receiving wavelength of the optical signal receiving filter to the wavelengths specified in a response message from the OLT and starts data communication.

Abstract: In a PON system by WDM, IP broadcast can be received without oppressing a band used by a user for Internet communication. An OLT provides a first wavelength received in common by respective ONUs and plural second wavelengths by which the OLT and the respective ONUs perform communication individually. With respect to signals in the downstream direction, each of the OLTs includes a transmitter to transmit the first wavelength and plural transmitters to transmit the second wavelengths used for the individual communication with the respective ONUs. Each of the ONUs includes a receiver to receive the first wavelength and a receiver to receive the second wavelength used in the ONU itself. The OLT transmits data of the IP broadcast by the first wavelength and transmits individual data of each of the ONUs by the second wavelength corresponding to the ONU.

Abstract: In a WDM type PON system, each ONU comprises an optical transmitter capable to transmit optical signals with variable wavelengths, an optical signal receiving filter variable its receiving wavelength, and a control unit. An OLT selects in response to a wavelength allocation request from each ONU, a transmitting wavelength and a receiving wavelength out of currently free wavelengths and allocates these wavelengths to the requester ONT. The control unit of the ONU switches the transmitting wavelength of the optical transmitter and the receiving wavelength of the optical signal receiving filter to the wavelengths specified in a response message from the OLT and starts data communication.

Abstract: The present disclosure provides a system and method for allocating bandwidth in remote equipment on a passive optical network (PON), wherein the system includes an optical line terminal (OLT), which monitors the acceptance of traffic requesting the PON remote equipment for service and configures through signaling control the parameters for the operation of classifying, shaping, and scheduling the traffic in the remote equipment, and a remote equipment which classifies, shapes, and schedules the accepted traffic based on the parameters configured by the OLT and allocates a proper bandwidth to the accepted traffic, and outputs the traffic in the scheduled order. The present disclosure helps ensure the bandwidth and delay requirements of individual traffic flows in the PON remote equipment are met and interaction between traffic of the same or different service class groups is eliminated.

Abstract: There is provided a wavelength division multiplexing transmission system and apparatuses used therein, in which a remote apparatus to be newly added to a station apparatus autonomously sets a wavelength to be used in the remote apparatus, thereby avoiding the need for presetting a wavelength to be used in the remote apparatus. The remote apparatus includes wavelength determining means that determines an available wavelength on the basis of an optical signal received from the station apparatus. The wavelength determining means may determine the wavelength of an unreceived optical signal as the available wavelength or may determine the wavelength of a received optical signal as the available wavelength, and may set that wavelength as a transmission and reception wavelength to be used in the remote apparatus.

Abstract: Light carrying information for access terminals is carried via optical fibers. Information for terminals from groups is multiplexed over different time-slots and different communication wavelengths of the light in the fiber for a group. The information is passed between the fibers and the transport network via transceivers. The use of the transceivers is multiplexed between the optical fibers. Each transceiver passes information for selectable light guides at selectable communication wavelengths in different timeslots.

Abstract: The invention relates to a rear panel bus, with a number of plugs which may be plugged into the modules and a fibre optic cable, for guiding light signals, whereby the fibre optic cable has a number of interruptions in the propagation direction of the light signals, into which means, for injection and decoupling of light signals running in the fibre optic cable may be inserted. The interruptions in the fibre optic cable are arranged such that a plug may be allocated to an interruption. The invention further comprises a module which may be plugged into an optical rear panel bus and means for injection and decoupling of light signals running in an optical fibre cable whereby the means for injecting and decoupling are arranged such as to be able to be inserted in interruptions in the fibre optic cable, to decouple light signals from the fibre optic cable and to inject light signals into the fibre optic cable in the propagation direction.

Abstract: Techniques are disclosed for generating a hitless migration plan to optimal state, given an optimal routing and wavelength assignment for demands. For example, a technique for use in performing a circuit transition in accordance with an optical ring-based network comprises the following steps/operations. First, a first (e.g., initial) circuit layout and a second (e.g., final) circuit layout for a given set of demands to be routed on the optical ring-based network are obtained. Then, a minimum number of free wavelengths required to transition the network from the first circuit layout to the second circuit layout is determined such that substantially no network service disruption occurs due to the circuit transition.

Abstract: A system and method of wavelength discovery in network elements having an optical architecture. In one embodiment, a first wavelength topology map is generated for wavelengths inserted in a first direction at each network element. A second wavelength topology map is generated for wavelengths inserted in a second direction at each network element. The first wavelength topology maps are transmitted in the first direction to adjacent network elements over a dedicated overhead wavelength channel. Similarly, the second wavelength topology maps are transmitted in the second direction to adjacent network elements over the dedicated overhead wavelength channel. Responsive to messaging via the dedicated overhead wavelength channel, each of the first and second topology maps are updated at each of the network elements.

Abstract: An improved method and apparatus is provided for transmitting a WDM optical signal. The method begins by modulating optical channels that are each located at a different wavelength from one another with (1) a respective one of a plurality of information-bearing electrical signals that all embody the same broadcast information; (2) a respective one of a plurality of RF signals having a common functional broadcast waveform, at least one of the RF signals being out of phase with respect to remaining ones of the plurality of RF signal and (3) at least one of the RF signals being phase adjusted with respect to its original phase. Each of the modulated optical channels is multiplexed to form a WDM optical signal. The WDM optical signal, while maintaining the pre-assigned phase relationships between the modulation signals of the optical channels, is forwarded onto an optical transmission path.

Abstract: A contents information delivery method for delivering a desired contents information by transmitting an optical signal from a central station to each of a plurality of user stations via a transmission line includes: a first step (S1) of outputting an optical signal containing the contents information as an optical signal having mutually different wavelengths each assigned for the each user station in advance, in the central station; a second step (S2) of transmitting an optical signal having a plurality of wavelengths outputted via the transmission line in the first step; and a third step (S3), in which each user station receives the optical signal having the wavelength assigned from among the transmitted optical signals, whereby, this simple configuration does not limit the transmission rate, the coding format, or the like in an optical access system, i.e., making it possible to cope with a super-large capacity.

Abstract: A transmission system for a passive optical network comprises a shared optical transmission apparatus, a shared electrical interface apparatus and a plurality of transmission convergence termination units. The shared optical transmission apparatus is configured for being coupled to an optical line termination unit via an optical fiber. The shared electrical interface apparatus is coupled to the shared optical transmission apparatus. The plurality of transmission convergence termination units is coupled to the shared electrical interface apparatus. Each one of the transmission convergence termination units is configured for selectively controlling the shared electrical interface apparatus.

Abstract: A channel switching function is added to a wavelength division multiplexing passive optical network (WDM-PON) system, which is an access optical network system, and the potential transmission rate is increased by combining wide wavelength tunable lasers and a time division multiplexing (TDM) data structure and properly using the necessary optical components. In addition, when the wavelength of a light source or an arrayed waveguide grating (AWG) changes, the wavelength is traced and the magnitude of a transmitted signal is maximized without an additional detour line using a loop-back network structure. Furthermore, fewer thermo-electric controllers (TECs) are required for stabilizing the temperature of an optical line terminal (OLT) using wavelength tunable lasers, each laser electrically changing its wavelength.

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.

Abstract: A method and system for ensuring confidentiality of signal transmission in a point-to-multi point data transmission network like Ether net passive optical network, including at least one hub, at least one transmission medium and at least one station connected to the hub via the transmission medium. When an upstream signal is transmitted from a first station, the upstream signal is reflected by at least one disturbing reflector for producing a disturbing reflection. The disturbing reflection combines with a second reflection of the upstream signal and renders the second reflection undependable by a second station.

Abstract: Methods and apparatus for scheduling transfer of data bursts in a network comprising electronic edge nodes interconnected by bufferless core nodes are disclosed. Each edge node comprises a source node and a sink node, and each core node comprises several bufferless space switches operating in parallel. Each space switch has a master controller and one of the master controllers in a core node functions as a core-node controller. Each master controller has a burst scheduler for computing a schedule for transfer of data bursts, received from source nodes, to respective destination sink nodes. A core-node controller receives requests for bitrate allocations from source nodes and assigns each request to one of the master controllers of the core node. In one embodiment, a scheduler determines schedules for concatenated reconfiguration periods. In another embodiment, parallel schedulers determine schedules for overlapping reconfiguration periods.

Abstract: The present provides a method of dynamically managing multicast groups and allocating multicast service wavelengths for the highest channel efficiency. According to the present invention, the share indices of wavelengths of all multicast service groups, which employ broadcasting wavelengths and data wavelengths, are periodically ascertained on the basis of IGMP snooping-based technology in a WDM-PON. Based on the ascertainment results, if the channel share index of the group that employs the broadcasting wavelength is smaller than the channel share index of the group that employs the data wavelength, the share index of the wavelength of the multicast group that employs the broadcasting wavelength is maximized by dynamically changing allocation of the wavelength of the multicast group, so that a maximum multicast service can be provided within limited resources.

Abstract: In the optical network system, light input to any of the optical input ports of the optical coupler is converted into light at another wavelength via a variable-wavelength optical receiver and an optical sender, and is then reinput to the optical coupler. This arrangement makes it possible to realize a full-mesh optical network system with a simple construction at low costs.

Abstract: The present invention provides a kind of ultra-wide band wireless system, which changes the previous electronic structure for ultra-wide band pulse generator, and uses light to generate pulse signal, transformed by microwave differentiator to Gaussian monocycle pulse transmission signal, the derived pulse signal can provide several GHz bandwidth to transmit fast speed information, and further complete the new ultra-wide band wireless system. It reduces the complexity of electronic system and enhances output signal quality by means of light property, with considerable leading advantage. And the signal generated by this system has broader band and no infringe property, its 10 dB band falls within the range prescribed by the Federal Communication Committee of United States (FCC), successfully realizing the ultra wide band fiberoptic wireless collection network system, and further attaining the goal of seamless communication collection.

Abstract: Modulators respectively modulate baseband signals into IF signals having different frequencies. A multiplexer multiplexes the IF signals. An electrical-optical converter intensity modulates the multiplexed IF signals into optical signals. A local oscillation signal source outputs a predetermined local oscillation signal. An external modulator intensity-modulates the optical signal using the local oscillation signal. An optical branching portion branches the intensity-modulated optical signal and respectively outputs branched optical signals to radio base stations. An optical-electrical converter converts the optical signal into an electric signal, to obtain an RF signal by frequency-converting the IF signal. An antenna only transmits a component having a desired radio frequency extracted in a band filter from the RF signal to a subscriber terminal.

Abstract: In a WDM type PON system, each ONU comprises an optical transmitter capable to transmit optical signals with variable wavelengths, an optical signal receiving filter variable its receiving wavelength, and a control unit. An OLT selects in response to a wavelength allocation request from each ONU, a transmitting wavelength and a receiving wavelength out of currently free wavelengths and allocates these wavelengths to the requester ONT. The control unit of the ONU switches the transmitting wavelength of the optical transmitter and the receiving wavelength of the optical signal receiving filter to the wavelengths specified in a response message from the OLT and starts data communication.

Abstract: In a WDM type PON system, each ONU comprises an optical transmitter capable to transmit optical signals with variable wavelengths, an optical signal receiving filter variable its receiving wavelength, and a control unit. An OLT selects in response to a wavelength allocation request from each ONU, a transmitting wavelength and a receiving wavelength out of currently free wavelengths and allocates these wavelengths to the requester ONT. The control unit of the ONU switches the transmitting wavelength of the optical transmitter and the receiving wavelength of the optical signal receiving filter to the wavelengths specified in a response message from the OLT and starts data communication.

Abstract: An optical-inclusive, dWDM local area network and the accompanying signaling protocol necessary to facilitate communication between nodes in a network. This network architecture provides for a packet-oriented network, independent of the number of nodes and the number of supported wavelengths, and provides for scheduled access to the medium, which guarantees higher utilization.

Abstract: The present invention is an optical fiber system and method for carrying both CATV and Ethernet signals. The digital signals are translated into higher band by a direct up/down conversion so that analog signals and digital signals are treated as different frequency bands of electrical signals. Then, all the signals are mixed/divided by a power combiner/divider. And then, by using optoelectronic devices, the signals are processed with optoelectronic conversion. The converted optical signals are transmitted in a fiber or a related optical channel having low channel loss yet high capacity. To sum up, the present invention can transmit digital signals together with analog signals in a single wavelength to save the cost of an optical signal system and to provide a convenience on rearranging the system.

Abstract: Provided is a WDM-PON system based on a wavelength-tunable ECL. A method of controlling an upstream optical wavelength of an ONT in WDM-PON system, the method comprises: determining upstream optical wavelength information of the ONT corresponding to a downstream optical wavelength predetermined to the ONT newly installed by being connected to a network; in an OLT, loading the determined upstream optical wavelength information onto the downstream optical wavelength assigned to the ONT and transmitting the loaded upstream optical wavelength information to the ONT; in the ONT, generating an upstream optical wavelength based on the upstream optical wavelength information transmitted by being loaded on the downstream optical wavelength from the OLT; and in the ONT, loading upstream data onto the generated upstream optical wavelength and transmitting the loaded upstream data to the OLT.

Abstract: Wavelength assignment schemes that provide full-connectivity in RANs with fixed-tuned OADMs. In the first scheme, wavelengths are assigned to nodes according to Hadamard code, and in the second scheme, bands of contiguous wavelengths are assigned to nodes. Simulation results show that on the average, the Hadamard wavelength assignment schemes approach the performance of RANs with OADMs that add-drop all wavelengths, while saving 50% of the TDM terminals. The saving of TDM terminals by using wavelength tunable OADMs vary in different cases. Tunable OADMs are advantageous for lower traffic granularity and more interactions of a RAN with the outside network.

Abstract: An optical access network system having a function of correcting upstream signal waveform distortions occurring in the PON section, wherein a central office side apparatus comprises a main controller to notify each subscriber connection apparatus of a transmission grant period, an equalizer of a tap gain adaptive control type to correct waveform distortions of signals received from the subscriber connection apparatuses, an equalizer controller, and a parameter table for storing, for each subscriber connection apparatus, the initial values of tap gains to be set for the equalizer. The main controller issues a switchover request for switching the equalization characteristic to the equalizer controller each time notifying a subscriber connection apparatus of a transmission grant period, and the equalizer controller retrieves the initial values of the tap gains for the subscriber connection apparatus from the parameter table in response to the switchover request, and sets these values to the equalizer.

Abstract: In a GPON system conforming to ITU-T Recommendations G.984.3, an optical line terminal is provided which has an active bandwidth allocation function that preferentially puts small bandwidth signals in a particular segment of a frame, e.g., at a head of the frame, to prevent fragmentations that may occur particularly when allocating small bandwidths of about 100 kbits/s.