Abstract: A transmission quality estimation system includes, three or more nodes and a transmission quality estimation device configured to estimate, transmission quality. A multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes. A node of the nodes includes a core connection unit configured to drop, add or relay light transmitted from, to or to each of to the plurality of cores of the multi-core fiber. The transmission quality estimation device includes an estimation unit configured to estimate transmission quality between the nodes on the basis of a transmission quality measurement light dropped by the core connection unit.

Abstract: A transmission quality estimation system includes, three or more nodes and a transmission quality estimation device configured to estimate, transmission quality. A multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes. A node of the nodes includes a core connection unit configured to drop, add or relay light transmitted from, to or to each of to the plurality of cores of the multi-core fiber. The transmission quality estimation device includes an estimation unit configured to estimate transmission quality between the nodes on the basis of a transmission quality measurement light dropped by the core connection unit.

Abstract: A communication system which includes: three or more nodes; a multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes; a detection signal output unit configured to output a fault detection signal transmitted by the core provided in the multi-core fiber configured to connect together the nodes; and a fault detection unit configured to determine whether a fault has occurred between the nodes on the basis of a detection result of the fault detection signal.

Abstract: A communication system includes three or more nodes and a multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of the connection between the nodes is provided. One node of the nodes is connected to the multi-core fiber and includes a connector configured to add and drop a signal to and from an allocated core exclusively allocated from among the cores as a communication path between the one node and another node of the nodes and/or configured to relay a signal transmitted through another core of the cores allocated for communication between other nodes in the multi-core fiber connected to the one node, and a relative positional relationship between a connection position of the allocated core in which a signal is added or dropped in the connector and a connection position of another core in which a signal is relayed in the connector is the same for all of the nodes connected to the multi-core fiber.

Abstract: A communication system includes three or more nodes, and a multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes, wherein each of nodes includes: a fault information transmitting device configured to transmit fault information indicating that a fault has occurred in a communication path between one node and another node of the nodes when it is detected that it is not possible to perform communication between the one node and the another node; and a fault location specifying device configured to specify a section between nodes in which a fault has occurred on the basis of the fault information received from the fault information transmitting device provided in each of the nodes.

Abstract: A communication system includes three or more nodes and a multi-core fiber having a plurality of cores and being used in at least a partial segment of the connection between the nodes. One node of the nodes is connected to the multi-core fiber and includes a connector configured to add and drop a signal to and from an allocated core exclusively allocated for communication between the one node and another node of the nodes and/or configured to relay a signal transmitted through another core allocated to communication between the other nodes in multi-core fibers connected to the one node.

Abstract: An optical amplification system includes: three or more nodes; a multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of the connection between the nodes; an amplification light input unit configured to input amplification light to a core of the plurality of cores of the multi-core fiber; an amplification unit configured to amplify communication light transmitted through at least one core of the plurality of cores of the multi-core fiber using the amplification light, the amplification unit being provided in the nodes or between the nodes; and an amplification light coupling unit configured to couple the amplification light input by the amplification light input unit to the amplification unit.

Abstract: A communication system which includes: three or more nodes; a multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes; a detection signal output unit configured to output a fault detection signal transmitted by the core provided in the multi-core fiber configured to connect together the nodes; and a fault detection unit configured to determine whether a fault has occurred between the nodes on the basis of a detection result of the fault detection signal.

Abstract: A communication system includes three or more nodes, and a multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes, wherein each of nodes includes: a fault information transmitting device configured to transmit fault information indicating that a fault has occurred in a communication path between one node and another node of the nodes when it is detected that it is not possible to perform communication between the one node and the another node; and a fault location specifying device configured to specify a section between nodes in which a fault has occurred on the basis of the fault information received from the fault information transmitting device provided in each of the nodes

Abstract: A communication system includes three or more nodes and a multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of the connection between the nodes is provided. One node of the nodes is connected to the multi-core fiber and includes a connector configured to add and drop a signal to and from an allocated core exclusively allocated from among the cores as a communication path between the one node and another node of the nodes and/or configured to relay a signal transmitted through another core of the cores allocated for communication between other nodes in the multi-core fiber connected to the one node, and a relative positional relationship between a connection position of the allocated core in which a signal is added or dropped in the connector and a connection position of another core in which a signal is relayed in the connector is the same for all of the nodes connected to the multi-core fiber.

Abstract: A node included in an optical power supply system which includes three or more nodes and a multi-core fiber having a plurality of cores, the plurality of cores being used in at least a partial segment of the connection between the nodes includes: a power supply light dropping unit configured to drop a portion or all of a power supply light from one core of the plurality of cores of the multi-core fiber; a photoelectric conversion unit configured to convert the portion or all of the power supply light dropped by the power supply light dropping unit to an electrical signal; and a power supply target facility configured to operate with the electrical signal converted by the photoelectric conversion unit.

Abstract: A transmission quality estimation system includes, three or more nodes and a transmission quality estimation device configured to estimate, transmission quality. A multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes. A node of the nodes includes a core connection unit configured to drop, add or relay light transmitted from, to or to each of to the plurality of cores of the multi-core fiber. The transmission quality estimation device includes an estimation unit configured to estimate transmission quality between the nodes on the basis of a transmission quality measurement light dropped by the core connection unit.

Abstract: In a wavelength division multiplexing optical transmission system, in order to know an influence amount of a temperature dependency of a dispersion slope, a method of monitoring a dispersion variation amount in two or more of wavelength channels is provided. Further, a method of compensating a wavelength dependency of a temperature dependency of the dispersion by providing an appropriate dispersion individually to the channels or summarizingly for all of bandwidths based on the monitored dispersion variation amounts is provided. According to the present invention, in the WDM optical transmission system, a deterioration in a transmission characteristic by influence of a temperature variation of the dispersion slope can be reduced.

Abstract: A chirp measurement apparatus includes a splitting section for splitting input signal light to two paths; a first dispersion medium with a total dispersion amount of +D (?0) at a used wavelength, and a second dispersion medium with a total dispersion amount of ?D (?0) at the used wavelength; first and second nonlinear photo-detecting sections for receiving the signal light beams passing through the first and second dispersion media, and for outputting electric signals with the intensities proportional to nth power of the intensities of the signal light beams, where n is greater than one; and a difference detecting section for computing a difference between the electric signals output from the first and second nonlinear photo-detecting sections, and for outputting a differential signal corresponding to the difference as a chirp signal of the input signal light.

Abstract: A chirp measurement apparatus includes a splitting section for splitting input signal light to two paths; a first dispersion medium with a total dispersion amount of +D (?0) at a used wavelength, and a second dispersion medium with a total dispersion amount of ?D (?0) at the used wavelength; first and second nonlinear photo-detecting sections for receiving the signal light beams passing through the first and second dispersion media, and for outputting electric signals with the intensities proportional to nth power of the intensities of the signal light beams, where n is greater than one; and a difference detecting section for computing a difference between the electric signals output from the first and second nonlinear photo-detecting sections, and for outputting a differential signal corresponding to the difference as a chirp signal of the input signal light.

Abstract: In a wavelength division multiplexing optical transmission system, in order to know an influence amount of a temperature dependency of a dispersion slope, a method of monitoring a dispersion variation amount in two or more of wavelength channels is provided. Further, a method of compensating a wavelength dependency of a temperature dependency of the dispersion by providing an appropriate dispersion individually to the channels or summarizingly for all of bandwidths based on the monitored dispersion variation amounts is provided. According to the present invention, in the WDM optical transmission system, a deterioration in a transmission characteristic by influence of a temperature variation of the dispersion slope can be reduced.

Abstract: The invention relates to a process for the fabrication of an optical fiber-processing phase mask that is reduced in terms of pitch variations on the mask and stitching errors, and provides a process for the fabrication of a chirped type optical fiber-processing phase mask wherein a grating form of grooves provided in one surface of a quartz substrate is configured as an optical fiber-processing grating pattern. At an exposure step, writing data obtained by arranging and compiling a plurality of data for a repetitive groove-and-strip pattern while the pitch of repetition is modulated are used and an electron beam resist is provided on a phase mask blank, so that writing is carried out all over the writing area on said phase mask blank continuously in a vertical direction to said grating form of grooves.

Abstract: A chirp measurement apparatus includes a splitting section for splitting input signal light to two paths; a first dispersion medium with a total dispersion amount of +D (?0) at a used wavelength, and a second dispersion medium with a total dispersion amount of ?D (?0) at the used wavelength; first and second nonlinear photo-detecting sections for receiving the signal light beams passing through the first and second dispersion media, and for outputting electric signals with the intensities proportional to nth power of the intensities of the signal light beams, where n is greater than one; and a difference detecting section for computing a difference between the electric signals output from the first and second nonlinear photo-detecting sections, and for outputting a differential signal corresponding to the difference as a chirp signal of the input signal light.

Abstract: A chirp measurement apparatus includes a splitting section for splitting input signal light to two paths; a first dispersion medium with a total dispersion amount of +D (?0) at a used wavelength, and a second dispersion medium with a total dispersion amount of ?D (?0) at the used wavelength; first and second nonlinear photo-detecting sections for receiving the signal light beams passing through the first and second dispersion media, and for outputting electric signals with the intensities proportional to nth power of the intensities of the signal light beams, where n is greater than one; and a difference detecting section for computing a difference between the electric signals output from the first and second nonlinear photo-detecting sections, and for outputting a differential signal corresponding to the difference as a chirp signal of the input signal light.

Abstract: The present invention relates to a precision phase mask for forming diffraction grating in optical fiber and optical waveguide, to provide them with nonlinear chirped grating for dispersion compensation use and having low fluctuation or crosstalk in the group delay characteristics. The diffraction grating is formed by means of interference fringe between diffracted lights of different orders, in which the cycle of the diffraction grating 20 increases nonlinearly, wherein plurality of diffraction gratings G1, G2, G3 . . . having different cycles are assembled on a plane in increasing order of the cycle with the directions of the diffraction gratings directed to the same direction, and assembled in such a manner that, where the cycle of grating changes nonlinearly and discontinuously, the regions having larger rate of change of the cycle contain proportionally more discontinuous phases per unit length.