Abstract: An object of the present invention is to provide an optical communication system and an optical communication method capable of achieving a long transmission distance with a passive element and obtaining redundancy of a ring topology. The optical communication system according to the present invention is a PON system having a ring configuration, in which an unequal branch optical splitter having a left-right symmetrical configuration is disposed in a trunk fiber wired in a loop shape. An OLT and an ONU have a configuration in which two sets of Tx (transmitter) and Rx (receiver) are mounted. Two sets of Tx (transmitters) and Rx (receivers) in each of a plurality of ONUs are respectively connected to left and right symmetrical ports of one unequally branched light beam SP.

Abstract: An optical communication system according to the present invention cancels waveform distortion due to wavelength dispersion by extracting the spectrum of a transmitted optical signal and passing the optical signal to a fiber having a dispersion value opposite to a dispersion amount corresponding to a transmission distance received by the spectrum component and compensates for a transmission path loss due to the fiber having the opposite dispersion value using optical splitters having different split ratios. With this configuration, the present invention can compensate for waveform distortion due to wavelength dispersion by a simple method in an access network and achieve an increase in the reachable transmission distance of the farthest user or an increase in the number of connectable users.

Abstract: An optical communication system configured with a station-side apparatus and a plurality of subscriber-side apparatuses in a bus network topology includes an optical amplification unit installed on a station side, and a drop unit configured to branch an optical signal and excitation light, wherein the optical amplification unit includes an amplifier configured to amplify a downlink signal, and an excitation light output unit configured to output the excitation light for amplifying an uplink signal to a communication path, and the drop unit changes a branching ratio in accordance with a wavelength of the optical signal so that a transmission loss of the excitation light with respect to a trunk fiber is reduced.

Abstract: An object of the present invention is to provide a light irradiation system capable of securing economic efficiency, flexibility, reliability, and safety, and further capable of reducing a transmission loss between a center side and a remote side. The present light irradiation system can secure economic efficiency by sharing a single light source installed on the center side with a plurality of irradiation places. The present light irradiation system can irradiate a place to be sterilized with ultraviolet light output by moving the optical fiber tip end on the remote side in a pinpoint manner, and can also secure flexibility. In addition, the present light irradiation system can secure reliability and safety by performing output control of the light source on the center side.

Abstract: An object of the present invention is to provide an ultraviolet light irradiation system and a decontamination method that are economical and easy to operate, and that can perform decontamination without any input from a user. In the present invention, an optical fiber or an optical waveguide that radiates ultraviolet light in a lateral direction, the optical fiber or the optical waveguide is built in a sheet shape, and irradiates a surface with the ultraviolet light. Specifically, a material in which a material having a high scattering coefficient is added to the optical fiber is used, a grating is formed in the optical fiber, the optical fiber is given a minute bending with a minute ruggedness, and an arbitrary bending is given on the optical fiber, or the like, thereby achieving side radiation. By such a feature, it has the effect that ultraviolet light decontamination can be performed at all times or at necessary timing for an object touched by an unspecified number of people.

Abstract: An object of the present invention is to provide an ultraviolet light irradiation system and a decontamination method that can perform decontamination economically without any input from a user. The ultraviolet light irradiation system forms a linear or planar ultraviolet light irradiation space by spatially bundling a plurality of ultraviolet light beams with high energy density or moving the ultraviolet light with high energy density at high speed. The ultraviolet light irradiation system can decontaminate a human body and clothing simply by passing through the space. Further, since the ultraviolet light irradiation system performs decontamination in the space, bacteria and viruses emitted from a carrier are not passed through the space.

Abstract: An object is to provide an optical communication system and an optical communication method that are capable of, when assigning wavelengths on a per-service basis and providing services on a per-area basis, preventing degradation of signal quality due to linear crosstalk and preventing an increase in cost and size. An optical communication system according to the present invention includes an optical splitter 300 connecting N first ports and M second ports by a combination of 2×2 fiber optical splitters, N and M each being an integer of two or more, where wavelengths of optical signals to be received are limited for each group of optical receivers 106, by using a correlation between a fused extension length of at least one 2×2 fiber optical splitter directly connected to the first port, among the 2×2 fiber optical splitters, and wavelength output characteristics of the second port of the optical splitter 300.

Abstract: An object is to provide an optical communication system capable of controlling the output ratio by port and by wavelength for incident light of different wavelengths, a method of determining the split ratio of an uneven-split optical splitter for controlling the output ratio by port and by wavelength, and a transmission range determination method for the optical communication system. The split ratio determination method for an uneven-split optical splitter according to the present invention uses the melt-draw distance to adjust the split ratio of each fiber-optic splitter included in the uneven-split optical splitter such that the light output from the farthest ONUs among each of the ports connected under the ports B to M of the uneven-split optical splitter arrives with the minimum reception sensitivity at OLT receivers in a PON system.

Abstract: It is an object of the present invention to provide a position measuring system, a position measuring device, and a method for measuring a position that can accurately measure the position of an object to be measured without being limited by an environment or an optical axis. A position measuring device 20 according to the present invention is characterized by including a light receiving unit 21 configured to receive scattered light Lsc emitted from a side surface of an optical fiber 50, a database 22 configured to store a correspondence between information on the scattered light and a position of the object to be measured, and a determination unit 23 configured to determine, based on the correspondence stored in the database, a position of the object to be measured from information on the scattered light received by the light receiving unit.

Abstract: In response to the above issue, an object of the present invention is to provide a diagnostic apparatus and a diagnostic method capable of accurately recognizing whether to use a long extension function at the time of relocation of an accommodation station of an OLT. The diagnostic apparatus according to an aspect of the present invention has an allowable line length list that is a relationship between a center wavelength and an allowable line distance that satisfies a selected spectrum width in an optical fiber used in an optical communication system, measures a center wavelength and a spectrum width of a spectrum for each ONU, matches the allowable line length list, and obtains an allowable line distance of each ONU.

Abstract: In order to solve the problems described above, an object of the present invention is to provide an optical communication system and a control method that automatically adjust a branching ratio of an optical splitter in accordance with a connection of a new ONU. An optical communication system according to the present invention causes an operation system or a DBA (Dynamic Bandwidth Allocation) function and a determining unit of a branching ratio of an optical splitter to cooperate with each other, adjusts the branching ratio so as to enable ranging with an active ONU, and takes into consideration an initial connection sequence through which an ONU is newly connected.

Abstract: An optical communication system according to the present invention cancels waveform distortion due to wavelength dispersion by extracting the spectrum of a transmitted optical signal and passing the optical signal to a fiber having a dispersion value opposite to a dispersion amount corresponding to a transmission distance received by the spectrum component and compensates for a transmission path loss due to the fiber having the opposite dispersion value using optical splitters having different split ratios. With this configuration, the present invention can compensate for waveform distortion due to wavelength dispersion by a simple method in an access network and achieve an increase in the reachable transmission distance of the farthest user or an increase in the number of connectable users.

Abstract: An object of the present invention is to provide an optical communication system and an optical communication method capable of achieving a long transmission distance with a passive element and obtaining redundancy of a ring topology. The optical communication system according to the present invention is a PON system having a ring configuration, in which an unequal branch optical splitter having a left-right symmetrical configuration is disposed in a trunk fiber wired in a loop shape. An OLT and an ONU have a configuration in which two sets of Tx (transmitter) and Rx (receiver) are mounted. Two sets of Tx (transmitters) and Rx (receivers) in each of a plurality of ONUs are respectively connected to left and right symmetrical ports of one unequally branched light beam SP.

Abstract: An objective of the present invention is to provide an optical measurement device capable of performing remote optical measurement. An optical measurement device may include a light source that generates irradiation light with a beam shape, a beam control unit configured to control an irradiation direction of the irradiation light L1, a condensing unit configured to condense returned light generated by irradiating a part of a measurement target with the irradiation light, and a detection unit configured to detect information regarding the measurement target included in the returned light condensed by the condensing unit. The beam control unit can control the irradiation direction of the irradiation light for measurement to any direction, and thus the condensing unit can efficiently receive the faint returned light from the measurement target.

Abstract: An object is to provide an optical communication system and an optical communication method that are capable of, when assigning wavelengths on a per-service basis and providing services on a per-area basis, preventing degradation of signal quality due to linear crosstalk and preventing an increase in cost and size. An optical communication system according to the present invention includes an optical splitter 300 connecting N first ports and M second ports by a combination of 2×2 fiber optical splitters, N and M each being an integer of two or more, where wavelengths of optical signals to be received are limited for each group of optical receivers 106, by using a correlation between a fused extension length of at least one 2×2 fiber optical splitter directly connected to the first port, among the 2×2 fiber optical splitters, and wavelength output characteristics of the second port of the optical splitter 300.

Abstract: An object is to provide an optical communication system capable of controlling the output ratio by port and by wavelength for incident light of different wavelengths, a method of determining the split ratio of an uneven-split optical splitter for controlling the output ratio by port and by wavelength, and a transmission range determination method for the optical communication system. The split ratio determination method for an uneven-split optical splitter according to the present invention uses the melt-draw distance to adjust the split ratio of each fiber-optic splitter included in the uneven-split optical splitter such that the light output from the farthest ONUs among each of the ports connected under the ports B to M of the uneven-split optical splitter arrives with the minimum reception sensitivity at OLT receivers in a PON system.

Abstract: To provide an optical communication system and an optical communication method able to achieve a high reliable access network capable of long haul distance transmission considering the optical energy efficiency even if the user distribution is biased. An uneven branch optical splitter included in an optical communication system according to the present invention can output the optical intensities different for each output port by adjusting the branching configuration and the branching ratio. For example, a reach transmission distance of the farmost user can be extended or the number of connectible users can be increased by adjusting the branching configuration of the uneven branch optical splitter or the branching ratios such that the near minimum reception sensitivity is given for the ONU installed near the telecommunications carrier.

Abstract: To provide an optical communication system and an optical communication method able to achieve a high reliable access network capable of long haul distance transmission considering the optical energy efficiency even if the user distribution is biased. An uneven branch optical splitter included in an optical communication system according to the present invention can output the optical intensities different for each output port by adjusting the branching configuration and the branching ratio. For example, a reach transmission distance of the farmost user can be extended or the number of connectible users can be increased by adjusting the branching configuration of the uneven branch optical splitter or the branching ratios such that the near minimum reception sensitivity is given for the ONU installed near the telecommunications carrier.