Abstract: An object of the present disclosure is to provide a phase OTDR, a signal processing device, and a signal processing method capable of reducing an influence of a phase connection error and improving visibility of a signal indicating a vibration change or a temperature change.

Abstract: An optical semiconductor element includes: a substrate; a semiconductor stacked body including an optical layer, a first semiconductor layer, and a second semiconductor layer, the optical layer and the first semiconductor layer forming a mesa portion and the second semiconductor layer including an outer portion; a first electrode formed on the mesa portion and connected to the first semiconductor layer; a first insulating layer formed on the first electrode; a second electrode including a first portion connected to the second semiconductor layer at the outer portion and a second portion arranged on the first insulating layer so as to overlap the first electrode; and a second insulating layer formed on the second electrode. An opening for exposing the first electrode is formed in the first insulating layer. An opening for exposing the second portion of the second electrode is formed in the second insulating layer.

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: According to present disclosure, there is provided a signal processing device as a phase OTDR that performs processing of averaging scattered light vector signals pertaining to a plurality of optical frequencies different from each other, by an optical frequency multiplexing technique, the signal processing device including: a functional unit that calculates a correction value for a phase offset between different optical frequencies per measurement data within a range of a time window having a predetermined window length; and a functional unit that executes correction for the phase offset the between different optical frequencies by performing processing of averaging measurement data, belonging to a middle of the time window and a timing later than the middle, by using the correction value with the time window kept moving in a time direction.

Abstract: The present disclosure is a facility position analysis device including: an optical signal feature extraction means for generating a feature point distribution waveform expressing a distribution of feature points in a longitudinal direction of an optical fiber under measurement, by extracting the feature points in a vibration distribution waveform measured by an optical fiber line vibration measuring device installed at one end of the optical fiber under measurement; a facility information waveform generation means for generating a facility information waveform expressing a distribution of facilities, connected to the optical fiber under measurement in a longitudinal direction of the optical fiber under measurement, based on interval information between the facilities; and a feature amount comparison means for relating facility information with the vibration distribution waveform, by comparing the feature point distribution waveform with the facility information waveform.

Abstract: An optical path testing device and an optical path testing method divide output light from a laser light source into a probe optical path and a local optical path and convert modulated light obtained by modulating input light of the probe optical path into probe light including pulsed light, generate a beat signal by causing signal light and input light of the local optical path to interfere with each other, acquire a signal indicating backscattered light in the optical fiber on the basis of the beat signal, and analyzes a loss distribution, when generating the modulated light, perform first modulation and second modulation, and generate an analysis signal by averaging the backscattered light in each different frequency band included in the beat signal between the different frequency bands and acquire the loss distribution by analyzing an intensity of the backscattered light included in the analysis signal.

Abstract: The present disclosure is an optical measurement system for measuring Rayleigh scattered light and Brillouin scattered light in an optical fiber by injecting light into both ends of the optical fiber, wherein injected light for the Rayleigh scattering includes frequency multiplexing pulses, and one pulse of the frequency multiplexing pulses is used as pump light for the Brillouin scattering.

Abstract: The present disclosure relates to a vibration measuring instrument that repeatedly injects a plurality of light pulses with different optical frequencies into an optical fiber, and performs distributed acoustic sensing-phase (DAS-P). In the vibration measuring instrument, light pulses having a waveform with a spectral side lobe smaller than a side lobe of a rectangular wave are used as the plurality of light pulses.

Abstract: The present disclosure provides an underground facility position contrast system S, which includes: a scattered light intensity distribution measurement device 1 for measuring, when an earthquake vibration is applied to an optical fiber F laid underground, a change over time in a scattered light intensity distribution in a longitudinal direction of the optical fiber F; and an underground facility position contrast device 2 for measuring a change over time in a distortion response distribution in the longitudinal direction of the optical fiber F based on the change over time in the scattered light intensity distribution in the longitudinal direction of the optical fiber F, estimating an underground facility state of the optical fiber F based on the change over time in the distortion response distribution in the longitudinal direction of the optical fiber F, and associating the underground facility position of the optical fiber F with a longitudinal distance of the optical fiber F.

Abstract: A signal processing device and a signal processing method of the present disclosure are a signal processing device and a signal processing method for performing signal processing of measurement data of scattered light, which is brought by scattering of a plurality of light pulses having different optical frequencies, in an optical fiber, and include calculating a scattered light vector ri with each of the optical frequencies of scattered light, falling within a predetermined time range in which measurement is allowed at any point of the optical fiber, averaging scattered light vectors ri with each of the optical frequencies in terms of the time range, calculating a rotation angle ?i for correcting a phase with each of the optical frequencies using a time average vector ri_avet obtained by the averaging, and correcting the phase of the scattered light vector ri with each of the optical frequencies by rotating the phase of the scattered light vector ri of each of the optical frequencies by the rotation angle ?i

Abstract: A method is presented for remotely identifying a utility pole position and estimating a state of an overhead optical fiber cable. The method includes 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: An optical path testing device and an optical path testing method divide output light from a laser light source into a probe optical path and a local optical path and convert modulated light obtained by modulating input light of the probe optical path into probe light including pulsed light, generate a beat signal by causing signal light and input light of the local optical path to interfere with each other, acquire a signal indicating backscattered light in the optical fiber on the basis of the beat signal, and analyzes a loss distribution, when generating the modulated light, perform first modulation and second modulation, and generate an analysis signal by averaging the backscattered light in each different frequency band included in the beat signal between the different frequency bands and acquire the loss distribution by analyzing an intensity of the backscattered light included in the analysis signal.

Abstract: An optical path testing device and an optical path testing method divide output light from a laser light source into a probe optical path and a local optical path and convert modulated light obtained by modulating input light of the probe optical path into probe light including pulsed light, generate a beat signal by causing signal light and input light of the local optical path to interfere with each other, acquire a signal indicating backscattered light in the optical fiber on the basis of the beat signal, and analyzes a loss distribution, generate the modulated light by performing, on the output light, modulation based on a frequency changing from a start frequency to an end frequency, generate an analysis signal by averaging the backscattered light in each different frequency band included in the beat signal between the different frequency bands and acquire the loss distribution.

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: 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 lithium secondary battery includes a positive electrode layer composed of a sintered body of lithium complex oxide, a negative electrode layer, a separator interposed between the positive electrode layer and the negative electrode layer, an electrolytic solution containing an electrolyte and a solvent and impregnated into the positive electrode layer, the negative electrode layer, and the separator, and an exterior body including a closed space in which the positive electrode layer, the negative electrode layer, the separator, and the electrolytic solution are accommodated. In a thickness direction of the positive electrode layer, a ratio of a thickness of the exterior body at a temperature of 80° C. and a pressure of 100 Pa to a thickness of the exterior body at a temperature of 25° C. and a pressure of 101325 Pa is 1.05 or more and 2.63 or less.

Abstract: A cable test system, an analysis apparatus, a cable test method, and a program are capable of recognizing a sag section of an overhead cable without sending a worker to a site. In some implementations, the cable test system includes an optical fiber vibration distribution measurement apparatus that acquires a vibration distribution waveform of an overhead optical fiber cable to be tested. The vibration distribution waveform being represented in a time domain and a distance domain in a longitudinal direction. The analysis apparatus that calculates a propagation speed of vibrations propagating through the overhead optical fiber cable from the vibration distribution waveform and detects, as a cable sag section, a section of the overhead optical fiber cable in which the propagation speed is equal to or lower than a threshold value.

Abstract: An object of the present disclosure is to enable vibration analysis using a spectral shift under appropriate conditions depending on a measurement object. According to the present disclosure, there is provided a vibration distribution measuring apparatus which measures backscattered light in an optical fiber to be measured a plurality of times at different times, extracts an optical spectrum of a window section determined from a plurality of backscattered light waveforms obtained by the measurement, and measures a vibration distribution in the optical fiber to be measured using optical spectra of the plurality of extracted backscattered light waveforms, in which the optical spectrum of the window section is calculated using the window section in which the vibration amplitude in the window section in the optical fiber to be measured is larger than a threshold value defined in the window section.

Abstract: A vibration detection apparatus is presented 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. 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: According to the present disclosure, provided is an optical fiber sensing system including: a path selection optical switch; an optical test device; and a first optical circulator inserted into an optical fiber targeted for measurement, in which in a situation where communication light goes toward the path selection optical switch, the first optical circulator is utilized for getting the test light entering the optical fiber targeted for measurement, and the path selection optical switch is activated for separating the backscattered light from the communication network, and in a situation where the communication light goes from the path selection optical switch, the path selection optical switch is activated for getting the test light, from the optical test device, entering the optical fiber targeted for measurement, and the first optical circulator is utilized for separating the backscattered light from the communication network.