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.

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: 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 disclosure is to provide a power coupling coefficient measurement method and a power coupling coefficient measurement device capable of inexpensively and easily measuring a power coupling coefficient. The power coupling coefficient measurement method according to the present disclosure is a power coupling coefficient measurement method for measuring a power coupling coefficient of a multi-core fiber in order to achieve the aforementioned object, and includes: inputting a test light pulse from one end of the multi-core fiber to any one of cores; receiving backscattered light of the core to which the test light pulse is input or any one of the other cores; measuring an intensity distribution of the backscattered light with respect to a distance from the one end of the multi-core fiber; and calculating the power coupling coefficient from the intensity distribution of the backscattered light.

Abstract: An object of the present invention is to provide an optical fiber sensing device and an optical fiber sensing method that enable accurate measurement even under the condition that strain or temperature change of a measurement target is significant. The present invention is an optical fiber sensing device using OFDR, including an analysis circuit that executes obtaining a change rate of a spectral by time-differentiating a measured spectrum shift, detecting a discontinuity point of the spectrum shift from the change rate, calculating a predicted value of the change rate for the discontinuity point, estimating an estimated value of the change rate at the discontinuity point by applying a Kalman filter to the change rate at the discontinuity point and the predicted value at the discontinuity point, and acquiring a corrected spectrum shift by time-integrating the change rate other than the discontinuity point and the estimated value estimated at the discontinuity point.

Abstract: A phase measurement method is presented which causes wavelength-multiplexed pulsed light to be incident on a measurement target optical fiber, produces a scattered light vector obtained by plotting scattered light from the measurement target optical fiber for each wavelength onto a two-dimensional plane having the in-phase component thereof on the horizontal axis and the orthogonal component thereof on the vertical axis, rotates the produced scattered light vector for each wavelength at each place in the measurement target optical fiber to align the directions of the vectors, generates a new vector by calculating the arithmetic average of the vectors having the aligned directions, and calculates the phase by using the values of the in-phase and orthogonal components of the generated new vector.

Abstract: A red-light emitting diode, LED, includes an active layer configured to generate red light, the active layer having first and second faces that are opposite to each other, a first barrier layer located on the first face of the active layer, a second barrier layer located on the second face of the active layer, a hole blocking layer located on the first barrier layer, opposite to the active layer, the hole blocking layer being configured to prevent holes to escape from the active layer, a first electrode located on the second barrier layer, and a second electrode located on the hole blocking layer. A bandgap of the hole blocking layer is larger than a bandgap of the first barrier layer.

Abstract: An object of the present disclosure is to provide a few-mode fiber testing method and a few-mode fiber testing device capable of acquiring a loss and inter-mode crosstalk for each mode at a connection point of a few-mode fiber by measurement only from one end of FUT.

Abstract: An optical fiber measurement system is presented. The optical fiber measurement system includes a light incident circuit which makes a probe light incident on one end of an optical fiber and makes a secondary probe light and a pump light as an optical pulse incident on the other end of the optical fiber; a light receiver which measures a light intensity of arbitrary one propagation mode in the probe light propagating through the optical fiber; and a control calculation device which sets a propagation mode of the probe light, the secondary probe light, and the pump light, an optical frequency difference of the secondary probe light, and an optical frequency difference of the pump light with respect to the light incident circuit, and calculates loss and crosstalk at each point in a longitudinal direction of the optical fiber from the light intensity measured by the light receiver.

Abstract: An object of the present invention is to propose a design method of a minimum value N of the number of multiplexed frequencies that is necessary for measuring an object vibrational frequency according to DAS-P while taking into consideration a trade-off between a measurement distance and an upper limit of a measurable vibrational frequency. When a phase change of an arbitrary section of a measured optical fiber is represented by A×sin(2?fvt), N=4Zfv/? is satisfied when A is smaller than ?/2 but N=2Zfv/(?·Arcsin (?/2A)) is satisfied when A is equal to or larger than ?/2, where fv represents vibrational frequency, t represents time, Z represents a length of the measured optical fiber (a measurement distance), and ? represents the speed of light inside the measured optical fiber.