Abstract: An optical fiber characteristics measurement apparatus (10) according to the present disclosure measures the characteristics of an optical fiber. The optical fiber characteristics measurement apparatus (10) includes a laser light source module (11) that outputs frequency-modulated laser light. The laser light source module (11) includes a laser light source (110) that outputs laser light, a laser light source driver (111) that modulates the frequency of the laser light outputted by the laser light source (110), and an optical amplifier (116) that adjusts the amplitude of the frequency-modulated laser light outputted by the laser light source (110) so as to cancel an amplitude modulation occurring in the frequency-modulated laser light outputted by the laser light source (110).

Abstract: An optical fiber characteristic measurement device (1) includes: a first optical splitter (12) that splits frequency-modulated modulated light (L1) into pump light (LP) and reference light (LR); a second optical splitter (16) that causes the pump light to be incident from one end of an optical fiber under test (FUT) and outputs Brillouin scattered light (LS) generated inside the optical fiber under test; a first detector (19) that detects interference light between the Brillouin scattered light output from the second optical splitter and the reference light; an analyzer (20) that obtains a Brillouin gain spectrum which is a spectrum of the Brillouin scattered light from a detection signal (S1) output from the first detector; a second detector (22, 31) that detects a double wave component having a frequency that is double a modulation frequency of the modulated light included in an intensity component of each frequency of the Brillouin gain spectrum obtained by the analyzer; and a measurer (23) that measures c

Abstract: An optical fiber characteristic measurement device (1, 2, 3) includes a photodetector (15, 15A) which detects Brillouin scattered light (LS) obtained by causing light to be incident on an optical fiber (FUT), an intensity acquisitor (16, 16A) which acquires a signal intensity at a prescribed reference frequency (f1, f2) from a detection signal (S1, S2, S3) output from the photodetector, and a measurer (18, 18A, 18B) which measures characteristics of the optical fiber by obtaining a peak frequency of a Brillouin gain spectrum, which is a spectrum of the Brillouin scattered light, from the signal intensity at the reference frequency acquired by the intensity acquisitor.

Abstract: An optical fiber characteristic measurement apparatus includes an arithmetic unit configured to measure the characteristic of an optical fiber under test by extracting multiple peaks in a Brillouin gain spectrum of Brillouin scatted light occurring in the optical fiber under test.

Abstract: An optical fiber characteristics measurement apparatus includes a first optical splitter that splits modulated light into pump light and reference light, a second optical splitter that causes the pump light to be incident on a fiber under test from one end and extracts Brillouin scattered light generated within the fiber under test, an adjuster that changes frequency of at least one of the reference light and pump light to a plurality of frequencies, and a calculator that measures characteristics of the fiber under test based on a second harmonic component among frequency components of a signal yielded by homodyne detection of interference light between the Brillouin scattered light and the reference light at each frequency, the second harmonic component having a frequency that is two times the modulation frequency of the modulated light.

Abstract: A signal detecting device includes a multiplier that multiplies a measurement signal by a reference signal, a filter that filters a multiplication result from the multiplier, a first storage that stores an internal state of the filter; and a second storage that stores a filtering result from the filter. The filter filters the multiplication result using the internal state stored in the first storage. The first storage switches an area in or from which the filter writes or reads the internal state in accordance with an index signal representing a type of amplitude of a time-divisional signal in the measurement signal. The second storage switches an area in which the filtering result is stored in accordance with the index signal.

Abstract: A temperature measuring device 10 includes a spectrum data acquirer 11 configured to acquire spectrum data that indicates a spectrum of Brillouin scattered light generated by causing light to be incident on an optical fiber FUT, a spectrum data analyzer 12 configured to analyze the spectrum data and to obtain a Brillouin frequency shift amount, a corrector 13 configured to predict an amount of change in the Brillouin frequency shift amount due to structural relaxation of the optical fiber FUT from a thermal history of the optical fiber FUT, and configured to correct the Brillouin frequency shift amount obtained by the spectrum data analyzer 12 using the predicted amount of change, and a temperature calculator 14 configured to obtain a temperature of the optical fiber FUT on the basis of the Brillouin frequency shift amount corrected by the corrector 13.

Abstract: A signal detecting device includes a multiplier that multiplies a measurement signal by a reference signal, a filter that filters a multiplication result from the multiplier, a first storage that stores an internal state of the filter; and a second storage that stores a filtering result from the filter. The filter filters the multiplication result using the internal state stored in the first storage. The first storage switches an area in or from which the filter writes or reads the internal state in accordance with an index signal representing a type of amplitude of a time-divisional signal in the measurement signal. The second storage switches an area in which the filtering result is stored in accordance with the index signal.

Abstract: An optical fiber characteristic measurement device (1) includes a light detector (16) configured to detect Brillouin scattered light (LS) obtained by causing light to be incident on an optical fiber (FUT); a signal processor (18b) configured to obtain, on the basis of a detection signal (S1) which is output from the light detector, a first Brillouin gain spectrum (B1) which is a spectrum of the Brillouin scattered light obtained in a case where a spectral width of the light incident on the optical fiber is a first width and a second Brillouin gain spectrum (B2) which is a spectrum of the Brillouin scattered light obtained in a case where the spectral width of the light incident on the optical fiber is a second width larger than the first width; and a measurer (18c) configured to measure characteristics of the optical fiber on the basis of the first Brillouin gain spectrum and the second Brillouin gain spectrum.

Abstract: An optical fiber characteristic measurement device (1, 2, 3) includes a photodetector (15, 15A) which detects Brillouin scattered light (LS) obtained by causing light to be incident on an optical fiber (FUT), an intensity acquisitor (16, 16A) which acquires a signal intensity at a prescribed reference frequency (f1, f2) from a detection signal (S1, S2, S3) output from the photodetector, and a measurer (18, 18A, 18B) which measures characteristics of the optical fiber by obtaining a peak frequency of a Brillouin gain spectrum, which is a spectrum of the Brillouin scattered light, from the signal intensity at the reference frequency acquired by the intensity acquisitor.

Abstract: An optical fiber sensor measuring apparatus includes a base portion, and a measuring optical fiber laid in the base portion. Adjacent linear portions of the measuring optical fiber are in contact with each other. The base portion may be plate-like. The measuring optical fiber may have the linear portion and a folded portion.

Abstract: An optical fiber sensor measuring apparatus includes a base portion, and a measuring optical fiber laid in the base portion. Adjacent linear portions of the measuring optical fiber are in contact with each other. The base portion may be plate-like. The measuring optical fiber may have the linear portion and a folded portion.