Abstract: Provided is an power and communications network convergence system including wireless base stations, and DC grid groups, each grid group belonging to a cell. Each grid in the grid group has a DC line to which devices including a power generator and a power-storage are connected, and performs, based on state-information on each device, first control for reducing power fluctuations in the line. A first grid belonging to a cell performs, based on state-information on each grid, second control for interchanging power with a second grid belonging to the cell. If a power situation of a first grid group belonging to a first cell and a power-situation of a second grid group belonging to a second cell satisfy a preset condition, the first grid group performs third control for interchanging power with the second grid group.

Abstract: A network system includes a network architecture including: a network layer configured to define an entirety of an electric power network constituted from electric power grids; a local network layer configured to define a local network corresponding to electric power grid groups and forming a part of the electric power network; a grid layer configured to define the electric power grids; a physical layer configured to define constituent elements included in the electric power grids; a first layer configured to define the information communication network that is associated with the network layer; a second layer configured to define the information communication network that is associated with the local network layer; a third layer configured to define the information communication network that is associated with the grid layer; and space, a fourth layer configured to define the information communication network that is associated with the physical layer.

Abstract: A power system includes: a direct-current bus to which a power generation device and a plurality of power devices are connected; and a plurality of battery devices connected at predetermined intervals from one end of the direct-current bus to another end and configured to supply and receive power to and from the direct-current bus.

Abstract: A network system includes: a wireless base station configured to relay communication performed by wireless terminals; distributed antennas each being configured to be connected to the wireless base station and form a cell that enables communication with the wireless terminals; direct-current grids each being arranged in a predetermined form in a communication area formed by the cells and configured to interchange power with power devices connected to the subject direct-current grid; a power gate arranged between the direct-current grids located adjacent to each other and configured to interchange power between the adjacent direct-current grids; and a control device configured to control the power gate based on information acquired from the power devices via the distributed antennas. The power devices connected to the direct-current grids are configured to perform communication with the control device via the distributed antennas that form the communication area including the direct-current grids.

Abstract: Provided is an power and communications network convergence system including wireless base stations, and DC grid groups, each grid group belonging to a cell. Each grid in the grid group has a DC line to which devices including a power generator and a power storage are connected, and performs, based on state information on each device, first control for reducing power fluctuations in the line. A first grid belonging to a cell performs, based on state information on each grid, second control for interchanging power with a second grid belonging to the cell. If a power situation of a first grid group belonging to a first cell and a power situation of a second grid group belonging to a second cell satisfy a preset condition, the first grid group performs third control for interchanging power with the second grid group.

Abstract: According to the present invention, a star-type wavelength multiplexed communication network using optical TX/RX devices capable of assigning the wavelengths can be provided without using the monitoring light. In an embodiment of the present invention, an optical TX/RX device for transmitting and receiving a wavelength-multiplexed signal light comprises an optical receiver capable of varying the RX wavelength and an optical transmitter capable of varying the TX wavelength. The optical TX/RX device detects RX wavelengths not in use via the optical receiver, and assigns the RX wavelength of the optical receiver to one of the RX wavelengths not-in-use, and assigns the TX wavelength of the optical transmitter to a TX wavelength corresponding to the RX wavelength according to a correspondence table of TX and RX wavelengths in the memory. Then, the optical TX/RX device transmits a signal light on this TX wavelength, and detects the response on the RX wavelength.

Abstract: In the present invention, the extremely complicated setting and control and an extremely expensive optical component (wavelength locker) are not required, and optical output wavelength and optical output power can simply be set and controlled at a moderate price. At least one value for determining a dependence of the optical output wavelength on drive current and device temperature and at least one value for determining a dependence of the optical output power on drive current and device temperature in a light emitting device constituting first means 1 for emitting light are stored in fourth means 4.

Abstract: A dual structure for a multiplexing section extended to an OSU is obtained without adding a dynamic function, such as an optical switch, to a W-MULDEM. The W-MULDEM of an optical wavelength division multiplexing access system divides, among ports corresponding to the individual ONUs, downstream optical signals having wavelengths ?d1 to ?dn, which are received along a current-use optical fiber, or downstream optical signals having wavelengths ?d1+?? to ?dn+??, which are received along a redundant optical fiber. The W-MULDEM also multiplexes, for the port that corresponds to the current-use optical fiber or the redundant optical fiber, upstream optical signals having wavelengths ?u1 to ?un or wavelengths ?u1+?? to ?un+??, which are received along optical fibers corresponding to the ONUs. A wavelength difference between the downstream optical signal and the upstream optical signal that are consonant with each ONU is defined as an integer times the FSR of an AWG.

Abstract: In the present invention, the extremely complicated setting and control and an extremely expensive optical component (wavelength locker) are not required, and optical output wavelength and optical output power can simply be set and controlled at a moderate price. At least one value for determining a dependence of the optical output wavelength on drive current and device temperature and at least one value for determining a dependence of the optical output power on drive current and device temperature in a light emitting device constituting first means 1 for emitting light are stored in fourth means 4.

Abstract: According to the present invention, a star-type wavelength multiplexed communication network using optical TX/RX devices capable of assigning the wavelengths can be provided without using the monitoring light. In an embodiment of the present invention, an optical TX/RX device for transmitting and receiving a wavelength-multiplexed signal light comprises an optical receiver capable of varying the RX wavelength and an optical transmitter capable of varying the TX wavelength. The optical TX/RX device detects RX wavelengths not in use via the optical receiver, and assigns the RX wavelength of the optical receiver to one of the RX wavelengths not-in-use, and assigns the TX wavelength of the optical transmitter to a TX wavelength corresponding to the RX wavelength according to a correspondence table of TX and RX wavelengths in the memory. Then, the optical TX/RX device transmits a signal light on this TX wavelength, and detects the response on the RX wavelength.

Abstract: An optical modulation apparatus is provided which implements a stable amplifying function by reducing the effect of reflected light rays from end faces of a bidirectional optical amplifier by imposing a numerical limitation on the relationship between the gain of the bidirectional optical amplifier and the loss of the optical modulator, or by inserting a polarization rotation section in a reflection type optical modulator including the bidirectional optical amplifier or in a multi-wavelength collective optical modulation system combining the multiple optical modulators. An optical modulation apparatus is provided which implements a stable amplifying function and cost reduction by reducing the effect of reflected light rays by interposing optical isolators at every alternate SOAs in a transmission-type optical modulation apparatus including a plurality of semiconductor optical amplifiers (SOAs) connected in a multistage fashion.

Abstract: The present invention provides wavelength monitoring and/or control enabling size reduction and low power operation without requiring a complicated optical system in its wavelength monitoring and controlling mechanism. The measurement portion (1) measures temperature by a thermistor (5) in the measurement portion, and measures a bias current by using an LD drive current detecting circuit (6). The LD temperature, optical output and bias current are measured by the measurement portion. The relationship between the LD temperature and wavelengths or between the temperature, bias current and wavelengths is stored in a memory map of the storage portion (2). The central controlling portion (3) calculates wavelengths on the basis of the temperature and the bias current or the temperature information of the measurement portion, and the relationship between the LD temperature, bias current and wavelengths or between the temperature and wavelengths of the storage portion.

Abstract: An optical wavelength division multiplexing network has a multi-level structure where a plurality of optical network units (ONUs) are connected to a lowest-level network. A node apparatus connected to networks other than the lowest-level network includes (a) passive optical components to branch optical signals from a higher-level network to a lower-level network, and couple optical signals from the lower-level network to the higher-level network, and (b) optical amplifiers for the optical signals. A node apparatus connected to the lowest-level network includes (a) an optical multiplexer/de-multiplexer to de-multiplex optical signals from the higher-level network, selectively output an optical signal to each ONU, and multiplex wave-length specific optical signals from the ONUs into a multiplexed optical signal, and (b) optical amplifiers for the optical signals.

Abstract: The present invention provides an optical wavelength-division multiple access system and a corresponding optical network unit. A wavelength band Da (wavelengths ?d1 to ?dn) for downlink optical signals corresponding to the n ONUs, a wavelength band Ua (wavelengths ?u1 to ?un) for uplink optical signals corresponding to the n ONUs, a wavelength band Db (wavelengths ?dn+1 to ?dn+m) for downlink optical signals corresponding to the m ONUs, and a wavelength band Ub (wavelengths ?un+1 to ?un+m) for uplink optical signals corresponding to the m ONUs are set different from one another, the wavelength bands Ua and Ub are set adjacent to each other, and the wavelength bands Ua and Da or the wavelength bands Ub and Db are set adjacent to each other.

Abstract: An optical modulation apparatus is provided which implements a stable amplifying function by reducing the effect of reflected light rays form end faces of a bidirectional optical amplifier by imposing a numerical limitation on the relationship between the gain of the bidirectional optical amplifier and the loss of the optical modulator, or by inserting a polarization rotation section in a reflection type optical modulator including the bidirectional optical amplifier or in a multi-wavelength collective optical modulation system combining the multiple optical modulators. An optical modulation apparatus is provided which implements a stable amplifying function and cost reduction by reducing the effect of reflected light rays by interposing optical isolators at every alternate SOAs in a transmission-type optical modulation apparatus including a plurality of semiconductor optical amplifiers (SOAs) connected in a multistage fashion.

Abstract: An optical modulation apparatus is provided which implements a stable amplifying function by reducing the effect of reflected light rays from end faces of a bidirectional optical amplifier by imposing a numerical limitation on the relationship between the gain of the bidirectional optical amplifier and the loss of the optical modulator, or by inserting a polarization rotation section in a reflection type optical modulator including the bidirectional optical amplifier or in a multi-wavelength collective optical modulation system combining the multiple optical modulators. An optical modulation apparatus is provided which implements a stable amplifying function and cost reduction by reducing the effect of reflected light rays by interposing optical isolators at every alternate SOAs in a transmission-type optical modulation apparatus including a plurality of semiconductor optical amplifiers (SOAs) connected in a multistage fashion.

Abstract: A first optical fiber transmission path is used to transmit continuous-wave light for upstream signal light from the center node to each of the remote nodes, while a second optical fiber transmission path is used to transmit downstream signal light from the center node to each remote node and to transmit upstream signal light (obtained by modulating continuous-wave light) from each remote node to the center node. In this network, specific wavelength bandwidths are allocated to each remote node for the continuous-wave lights (for upstream signal lights) and the downstream signal lights, and the wavelength bandwidths for the continuous-wave lights (for upstream signal lights) and the downstream signal lights are alternately set.

Abstract: In an optical wavelength division multiplexed access system, a center unit (OSU) and n optical network units (ONUs) are connected together via a wavelength splitter and optical fiber transmission lines, and downstream optical signals from the OSU to the ONUs and upstream optical signals from the ONUs to the OSU are transmitted in both directions, the wavelength spacing ??d (optical frequency spacing ?fd) of the downstream optical signals is set to twice or more the wavelength spacing ??u (optical frequency spacing ?fu) of the upstream optical signals, each ONU transmits an upstream optical signal whose optical spectral width is twice or more ??u (?fu), and the wavelength splitter spectrum slices the upstream signals transmitted from the ONUs into wavelengths (optical frequencies) whose optical spectral widths are mutually different within ??u (?fu), and wavelength-division multiplexes them and transmits to the OSU.

Abstract: An optical wavelength division multiplexing network has a multi-level structure where a plurality of optical network units (ONUs) are connected to a lowest-level network. A node apparatus connected to networks other than the lowest-level network includes (a) passive optical components to branch optical signals from a higher-level network to a lower-level network, and couple optical signals from the lower-level network to the higher-level network, and (b) optical amplifiers for the optical signals. A node apparatus connected to the lowest-level network includes (a) an optical multiplexer/de-multiplexer to de-multiplex optical signals from the higher-level network, selectively output an optical signal to each ONU, and multiplex wave-length specific optical signals from the ONUs into a multiplexed optical signal, and (b) optical amplifiers for the optical signals.

Abstract: An optical wavelength division multiplexing network which can carry out large-capacity access service with a simple constitution is provided. In an optical network comprising a plurality of layers, a highest level network comprises a ring network having a center node and remote nodes; an intermediate level network comprises a ring centered around a node belonging to the higher level network, and a lowest level network comprises a star network centered around an access node which multiplexes traffic from a plurality of ONU, the ONU and the access node being directly joined together by optical fibers; the center node belonging to the highest level network and the ONU establish a direct communication path by using lights of different wavelengths; at nodes provided therebetween, the optical signals are not electrically processed but are amplified, branched, and routed.