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: An object of the present invention is to provide a Brillouin gain spectrum distribution measuring method and apparatus capable of measuring a BGS, having a line width narrower than usual, in a distributed manner in the longitudinal direction of an optical fiber under test. This measuring apparatus prepares pump light in which a pulse is added to continuous light and probe light of continuous light in which a frequency is shifted from the pump light, makes the probe light incident on one end of the FUT and the pump light incident on the other end, and obtains a time waveform of a component amplified by the pump light pulse of a probe light intensity amplified by the pump light. This measuring apparatus changes an optical frequency difference between the pump light and the probe light, and obtains a time waveform for each optical frequency difference. This measuring apparatus obtains a BGS distribution of the FUT from these time waveforms.

Abstract: An object of the present invention is to provide a Brillouin optical sensing device and an optical sensing method capable of reducing introduction costs. The Brillouin optical sensing device according to the present invention includes: a sensing fiber 90 in which a plurality of optical fibers having Brillouin frequency shift characteristics different from each other are arranged in parallel; an optical measuring instrument 11 that launches an optical pulse into at least two of the optical fibers of the sensing fiber 90 to generate Brillouin scattering lights and measures a beat frequency of a beat signal between the Brillouin scattering lights at any position of the sensing fiber 90; and an arithmetic processing unit 12 that acquires a physical quantity of the sensing fiber 90 at said any position based on the beat frequency acquired by the optical measuring instrument 11.

Abstract: An object of the present disclosure is to provide a method for remotely identifying a utility pole position and estimating a state of an overhead optical fiber cable. The present disclosure is a method for identifying a utility pole position including identifying a boundary region of a vibration distribution as a utility pole position, from a vibration distribution pattern obtained by measuring strain amounts with respect to distances of an optical fiber by an optical fiber vibration distribution measuring method at each time and sequentially stacking the strain amounts.

Abstract: A measuring device includes a first space for pressurizing a pressurization target and a second space independent of the first space. The measuring device includes a first exhaust valve closing or opening a communication port communicating the first space with another space. An open/closed state of the first exhaust valve changes in accordance with a pressure difference between the first space and the second space.

Abstract: The present disclosure is an optical line test system that detects a distribution of loss points of an optical line in a longitudinal direction, using a coherent light measurement device, applies vibration to facility disposed on a path of the optical line, detects a vibration point of the optical line in a longitudinal direction upon applying the vibration, using the coherent light measurement device, and identifies the loss point based on correspondence between the detected loss point and vibration point.

Abstract: A light-emitting diode element includes a semiconductor substrate having a first surface and a second surface on a side opposite to the first surface, a semiconductor lamination portion formed on the first surface of the semiconductor substrate, a first electrode connected to a part of the semiconductor lamination portion on the semiconductor substrate side, and a second electrode connected to a part of the semiconductor lamination portion on a side opposite to the semiconductor substrate. The semiconductor lamination portion includes an n-type semiconductor layer, an active layer having a p-type conductivity and laminated on the n-type semiconductor layer, and a p-type semiconductor layer laminated on the active layer on a side opposite to the n-type semiconductor layer. The active layer has a multiple quantum well structure constituted of barrier layers including AlInAs and well layers including InAsSb alternately laminated therein.

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 invention is to provide a facility position specification system, a cover, and a facility position specification method capable of specifying a route of an overhead cable without directly giving disturbance to the overhead cable itself.

Abstract: The purpose of the present disclosure is to provide a mode field diameter test method and test device that enable acquisition of a mode field diameter for an arbitrary higher-order mode. The present disclosure is a mode field diameter test method including: a test light incidence procedure for selectively causing test light to be incident in a mode subject to measurement, on one end of an optical fiber 10 under test; a far-field pattern measurement procedure for measuring a far-field pattern of the mode subject to measurement, with respect to a divergence angle ? at the other end of the optical fiber under test, by a far-field scanning technique; and a mode field diameter calculation procedure for calculating, using an equation, a mode field diameter from information about incident mode orders in the test light incidence procedure and the far-field pattern measured in the far-field pattern measurement procedure.

Abstract: An optical fiber testing method is presented for measuring the change amount for the wave number k of a Brillouin Frequency Shift ? in stimulated Brillouin scattering generated in the same acoustic mode with respect to each target propagation mode. In this way, the ratio of the change amount measured at each propagation mode is acquired as the group delay ratio between the modes.

Abstract: It is intended to provide a phase measurement method and a signal processing device that are capable of reducing influence of noise of a measuring device without increasing the peak intensity of an incident light pulse when measuring the phase of scattered light in DAS-P.

Abstract: A vibration detection method is presented to accurately detect vibration physically applied to an optical fiber, using a simple determination reference. In a vibration detection method, scattered light of a given target segment of a measurement target fiber is indicated by vectors of an in-phase component and a quadrature component, and a triangular shape constituted by a near-end-side vector of the target segment and a far-end-side vector is used as a physical amount to be tracked. That is, it is determined whether or not there is vibration based on a change in shape of the triangular shape with respect to a reference state. This is a detection method in which DAS-I and DAS-P are combined, a simple determination reference such as shape change of a triangular shape is employed, and overlooking of vibration detection can be reduced.

Abstract: The present disclosure relates to a frequency modulation amount measuring device that measures an optical spectral shift of scattered light at a position in an optical transmission line, and calculates a frequency modulation amount at the position, using the measured optical spectral shift.

Abstract: A light emitting diode element includes: a first element portion including a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a first active layer; and a second element portion including a third semiconductor layer of the first conductivity type, a fourth semiconductor layer of the second conductivity type, and a second active layer. The first and second element portions are electrically connected to each other by a tunnel junction portion. When the first conductivity type is n-type, the first element portion includes an electron barrier layer arranged between the first active layer and the tunnel junction portion. When the first conductivity type is p-type, the second element portion includes an electron barrier layer arranged between the second active layer and the tunnel junction portion. The electron barrier layer includes AlGaAsSb or AlInAsSb.

Abstract: An object is to provide a vibration detection apparatus and a vibration detection method which can avoid occurrence of a point where detection sensitivity deteriorates in vibration detection of a scattered light intensity monitor according to optical frequency multiplexing. The present invention conceives a multi-dimensional space having as many dimensions as the number of frequencies to be used, causes scattered light intensity change at each optical frequency to correspond to each axis, plots a scattered light signal as a vector on the space, performs linear approximation passing through an origin on the space having a plurality of plotted vector points as original data, and performs vibration detection using a direction vector of an approximate straight line obtained as a result of the approximation.

Abstract: The present disclosure aims to enable measurement of a long distance exceeding 1 km with a spatial resolution of 100 ?m or lower, and diagnosis of health of an optical device installed at a long distance. An apparatus according to the present disclosure is an optical frequency domain reflectivity measuring apparatus that includes: a local light delay fiber that delays local light; an optical 90-degree hybrid that receives an input of the local light delayed by the local light delay fiber and backscattered light from the measurement target, causes the local light and the backscattered light to interfere with each other, and generates an in-phase component and an orthogonal component of a beat signal generated by the interference; and a balance photodetector that detects the in-phase component and the orthogonal component of the beat signal. In the apparatus, an optical frequency response of the measurement target is measured with respect to a relative distance based on the local light delay fiber.

Abstract: An object of the present invention is to provide an optical fiber measurement system, an optical fiber measurement method, a control calculation device, and a program that are capable of measuring loss and XT occurring at a plurality of points of an optical fiber in which a plurality of modes propagate, for each point.

Abstract: An object of the present disclosure is to provide a method and an apparatus for acquiring curvature and torsion using an inexpensive sensor medium. Disclosed is a measurement apparatus including a fiber ribbon including a plurality of coated fibers arranged in parallel, a strain measurement unit that measures strain amounts of the plurality of coated fibers, and an arithmetic processing unit that calculates curvature and torsion of the fiber ribbon using a strain amount of a coated fiber arranged in a middle portion of the plurality of coated fibers and a strain amount of a coated fiber arranged in a marginal portion of the plurality of coated fibers.

Abstract: A light intensity distribution measurement apparatus is presented that is capable of accurately measuring the intensity of light in each mode at each position of an optical fiber through which light is propagated in a plurality of modes.