Abstract: An object is to provide an optical fiber path search method, an optical fiber path search system, a signal processor, and a program that can be operated free of the effects of walls, supporting members, and the like so that only a signal generated by an acoustic wave propagating through the air can be extracted.

Abstract: A vibration distribution measurement system includes a frequency sweep light source that outputs frequency sweep light, an optical splitter that splits the frequency sweep light into probe light and local light, an optical mixer that mixes backscattered light from the sensing fiber as signal light with the local light, the backscattered light being obtained by causing the probe light to be incident on the sensing fiber, and an analysis unit that analyzes a beat signal obtained from output light of the optical mixer. The analysis unit estimates a distance offset from a measurement result obtained by measuring a distribution waveform of the signal light by measuring the beat signal at a measurement time sufficiently shorter than a cycle of the vibration of the sensing fiber, and measures a distribution of a vibration at any position by compensating for the distance offset.

Abstract: An object of the present disclosure is to provide an optical coupling device capable of controlling a coupling rate of optical coupling between two coupling optical fibers. An optical coupling device of the present disclosure includes two coupling optical fibers each including a core and a clad and, between the two coupling optical fibers, a thickness variable member having a thickness between the two coupling optical fibers that varies by irradiation with light.

Abstract: An object of the present disclosure is to provide an optical coupling device capable of controlling a coupling index of optical coupling between two optical fibers for coupling. An optical coupling device of the present disclosure includes two optical fibers for coupling having a core and a clad, and a refractive index variable member to change the refractive index by irradiation with light between the two optical fibers for coupling.

Abstract: A manhole position identification method of the present invention includes: measuring, from an end of an optical fiber, a temporal variation in scattering light from the optical fiber when an impact blow is applied to a cover of a manhole located on a path of the optical fiber, so as to obtain temporal variations in a scattering light intensity distribution in a longitudinal direction of the optical fiber; determining an occurrence of vibration due to the impact blow based on the temporal variations at positions in the scattering light intensity distribution, so as to identify an impact blow position on the optical fiber; and associating the impact blow position on the optical fiber with a map position of the manhole whose cover has received the impact blow, so as to identify a position of the manhole expressed in terms of optical fiber length from the end.

Abstract: The present disclosure intends to provide an optical signal from an ONU according to a desired service usage state without using the ONU and an OLT. A simulated signal light generation apparatus 10 according to the present disclosure is a simulated signal light generation apparatus 10 for simulating an uplink signal light generated in an optical network unit (ONU) in a passive optical network (PON), and the apparatus includes a usage state control unit 11 that sets a service usage state of the ONU, a signal generation unit 12 that generates an uplink signal frame according to the usage state set by the usage state control unit 11, and an electrical/optical conversion unit 13 that converts an electrical signal from the signal generation unit 12 into an optical signal, and the optical signal from the electrical/optical conversion unit 13 is repeatedly transmitted to an optical fiber core 22.

Abstract: An object of the present invention is to provide a Raman gain efficiency distribution testing method and a Raman gain efficiency distribution testing apparatus for measuring a Raman gain efficiency distribution of a fundamental mode and a first high-order mode in a few-mode fiber.

Abstract: An optical fiber loss measurement device includes a unit configured to input pump light at a first frequency in a predetermined mode to a measurement target optical fiber in which a plurality of modes propagate from a first end, and input probe light at a second frequency to which a Brillouin frequency shift is applied to a second end, a Brillouin gain acquisition unit configured to measure an intensity of light output from the first end to acquire Brillouin gains in a longitudinal direction of the measurement target optical fiber using a BOTDA method, and a unit configured to measure a loss in the predetermined mode of the measurement target optical fiber, and the probe light is in a mode in which an electric field distribution in a cross section of the measurement target optical fiber is axisymmetric.

Abstract: An object of the present disclosure is to provide a frequency division multiplexing coherent OTDR, a test method, a signal processing apparatus, and a program that can maintain, even in a case where a DFB laser is used, a spatial resolution equivalent to a spatial resolution achieved when a fiber laser or an external resonant laser is used.

Abstract: An optical test system capable of accurately measuring a loss of each mode at each position of an optical fiber which propagates a plurality of modes is provided.

Abstract: An optical fiber side input and output device in which light can be input and output from the side of the tube core cable without adjusting a spacing even in a case where the thickness of the protective tube differs, and a method of designing the optical fiber side input and output device is provided. An optical fiber side input and output device has a structure in which an angle of a central angle of an apex portion of a first jig having a convex portion is appropriately set, and a loss insertion is kept equal to or less than a prescribed value by using a relationship between a spacing at the angle and an insertion loss when light is input and output from the side of the tube core cable.

Abstract: An environmental property measurement apparatus includes a unit configured to receive probe light in a desired mode from one end of a measurement optical fiber, a unit configured to receive, from the other end of the measurement optical fiber, a light pulse in the desired mode as a pump light pulse with respect to the probe light, the light pulse having a frequency difference corresponding to a Brillouin frequency shift of the measurement optical fiber relative to the probe light on a high frequency side, and a unit configured to receive second probe light having the frequency difference corresponding to the Brillouin frequency shift of the measurement optical fiber relative to the probe light on a low frequency side from the other end of the measurement optical fiber, the second probe light being probe light with respect to the probe light in another mode different from the desired mode.

Abstract: An object is to provide a propagation property analyzing apparatus that can alleviate the influence of an error caused by crosstalk, and accurately evaluate a few-mode optical fiber that multiplexes a plurality of modes, in a distributional and non-destructive manner.

Abstract: An object of the present invention is to provide a Raman gain efficiency distribution testing method and a Raman gain efficiency distribution testing apparatus for measuring a Raman gain efficiency distribution of a fundamental mode and a first high-order mode in a few-mode fiber.

Abstract: An object is to provide a highly versatile optical fiber local-light detection apparatus capable of supporting various types of coated optical fibers.

Abstract: Provided is an optical spectrum line width calculation method, apparatus, and program capable of calculating a spectrum line width of a laser to be measured from an optical interference signal generated by an optical interferometer having a delay line, based on a phase of the optical interference signal having a delay time longer than a delay time due to the delay line. The optical spectrum line width measurement apparatus includes a Mach-Zehnder interferometer, an optical receiver that receives an optical interference signal emitted from the Mach-Zehnder interferometer, an A/D converter that converts an analog electric signal output from the optical receiver into a digital electric signal, and a processing apparatus that processes the digital electric signal. Two light beams having a delay difference ? are generated from light emitted from the laser to be measured, and an optical interference signal is generated by multiplexing the two light beams.

Abstract: A distributed optical fiber vibration measurement device includes a phase constant difference computation unit causing the first backscattered light generated at the points of a plurality of optical fibers under test that are integrated to interfere with another light to obtain two AC components and determining a phase constant difference from the two AC components, a phase distribution data creation unit comparing amplitudes between the two AC components obtained by causing the first backscattered light generated at the points of the optical fibers under test to interfere with the other light and selecting, for each of the points, phase data regarding one of the two AC components having a larger amplitude to create phase distribution data with the phase data, and a vibration measurement unit identifying an optical path length difference between any two points of the optical fiber under test to measure vibration of the optical fiber under test.

Abstract: Provided is a feature for a heated tobacco product having a tobacco rod formed by filling the inside of wrapping paper with a tobacco filler containing a tobacco raw material and an aerosol-source material, that prevents damage to an electric heater, such as bending or curving, during insertion into the tobacco rod, prevents the tobacco filler constituting the tobacco rod from being pressed toward the mouth end, and prevents the tobacco rod from deforming by buckling. This heated tobacco product has a tobacco rod formed by filling the inside of wrapping paper with a tobacco filler containing cut tobacco and an aerosol-source material, and is provided with a heater-insertion cavity that is open on the distal end surface side of the tobacco rod and extends in the axial direction of the tobacco rod, and into which a heater of a heating device is inserted.

Abstract: Provided is a feature that, during storage of a heated tobacco product having a tobacco rod formed by filling the inside of wrapping paper with a tobacco filler containing a tobacco raw material and an aerosol-source material, suppresses occlusion of a heater-insertion cavity open on the distal end surface side of the tobacco rod. This heated tobacco product has a tobacco rod formed by filling the inside of wrapping paper with a tobacco filler containing cut tobacco and an aerosol-source material, and is provided with: a heater-insertion cavity that is open on the distal end surface side of the tobacco rod and extends in the axial direction of the tobacco rod, and into which a heater of a heating device is inserted; and a coating layer that is formed on the lateral periphery of the heater-insertion cavity of the tobacco rod, and suppresses occlusion of the heater-insertion cavity.

Abstract: An object of the present invention is to provide an optical pulse test apparatus that can test an optical fiber cable at once in a short period of time.