82 results about "Brillouin gain" patented technology

The invention belongs to the field of distributed optical fiber sensing, and provides a Brillouin temperature extraction method and system based on a self-attention recurrent neural network, and the method comprises the steps: collecting real Brillouin gain spectrum data through a Brillouin optical time domain analysis system which is built in advance, and carrying out the preprocessing of the real Brillouin gain spectrum data; based on the preprocessed Brillouin gain spectrum data, utilizing the trained self-attention recurrent neural network model to obtain a corresponding Brillouin temperature; a meta-learning algorithm is introduced in the process of a self-attention recurrent neural network model, so that the network model can share initialization parameters among a plurality of tasks, the parameters are optimized through meta-training, the network model can quickly adapt to a new task, training from zero is not needed in the face of multi-task learning or the new task, and the training efficiency is improved. The model can be quickly adjusted through a small amount of gradient updating, the training time is shortened, the performance is improved, and the problems of long time, poor real-time performance, poor adaptability and the like of curve fitting are solved.

Methods and systems for fiber identification include emitting a pump pulse on a fiber using a transponder. A Brillouin gain spectrum of reflected radiation from the pump pulse is measured using the transponder. A fiber type is determined corresponding to the Brillouin gain spectrum.

The invention discloses an integrated Brillouin narrow linewidth laser and a preparation method thereof, and belongs to the field of integrated photonics. The integrated Brillouin narrow linewidth laser is composed of two layers of silicon nitride micro-rings, a silicon oxide spacing layer is arranged between the two layers of silicon nitride micro-rings, the free spectral path of the two layers of silicon nitride micro-rings is designed to be Brillouin frequency shift, and coupling waveguides are designed beside the micro-rings. The invention also provides a corresponding preparation method, which comprises the following steps of: sequentially depositing the first silicon nitride layer, the first silicon oxide layer, the second silicon nitride layer, the second silicon oxide layer and the etching pattern on the substrate, and finally depositing silicon oxide as a protective layer. The TM mode is intensively distributed in the silicon oxide between the two layers of silicon nitride through the constraint of the two layers of silicon nitride micro-rings, the defect that the Brillouin gain of a silicon nitride material is weak is overcome, the mode size is reduced, the Brillouin threshold value is reduced, and high-efficiency output of the Brillouin narrow linewidth laser is achieved.

The invention provides a BOTDR system Brillouin gain spectrum correction method and system based on a symmetric kernel, and belongs to the technical field of optical fiber sensing. The method comprises the following steps: acquiring Brillouin gain spectrum information along a sensing optical fiber; acquiring amplitude-frequency responses of the balanced photoelectric detector and the band-pass filter in a full frequency band by using a vector network analyzer; performing convolution processing on the obtained Brillouin gain spectrum information along the sensing optical fiber and the amplitude-frequency response of the balanced photoelectric detector and the band-pass filter in the full frequency band to obtain a corrected Brillouin gain spectrum; lorentz fitting is carried out on the corrected Brillouin gain spectrum to extract Brillouin frequency shift, and the Brillouin frequency shift is converted into temperature and strain information. The spectral line symmetry and the signal-to-noise ratio are improved, the symmetry of the corrected Brillouin gain spectrum is remarkably enhanced, the phenomena of peak offset and asymmetric broadening caused by system bandwidth limitation are eliminated, and the extraction precision of the Brillouin gain spectrum is remarkably improved.

The invention relates to the technical field of optical fiber sensing, and provides a coefficient compensation device and method for correcting Brillouin gain spectrum distortion of a BOTDA (Brillouin Optical Time Domain Analysis). The compensation device comprises a laser and a coupler, the probe light branch optical path emits probe light into the sensing optical fiber, the pump branch optical path emits pump light into the sensing optical fiber, a stimulated Brillouin scattering effect is generated in the sensing optical fiber, and a probe light signal carrying Brillouin scattering information is obtained; the optical fiber Bragg grating filters an incoming detection light signal to obtain a first single side band signal; the detector converts the first single side band signal into a Brillouin scattering signal and inputs the Brillouin scattering signal into the processing module; the industrial personal computer is used for acquiring power fluctuation characteristics of the probe light under different frequencies when the coefficient compensation device does not generate the stimulated Brillouin scattering effect so as to calculate a compensation coefficient; and when the stimulated Brillouin scattering effect occurs, compensating the Brillouin scattering signal output by the detector by using the compensation coefficient to obtain the compensated Brillouin scattering signal.

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.

The invention relates to the technical field of optical fibers, in particular to a Brillouin gain-loss dual-mechanism type optical fiber sensing monitor and a control method. According to the monitor, a laser beam emitted by a fixed wavelength laser is divided into two paths of optical signals through a polarization-maintaining coupler, one path of optical signals enters a pump pulse light path, and the other path of optical signals enters a probe light path; pump pulse light generated by the pump pulse light path and probe light generated by the probe light path respectively enter the single-mode sensing optical fiber. After the continuous probe light and the pump pulse light generate a stimulated Brillouin scattering effect in the single-mode sensing optical fiber, a generated backward Brillouin scattering signal enters the photoelectric detector to be converted into an electric signal, and the computer processes the input electric signal to complete the measurement and demodulation processes; wherein the computer controls the optical adjustable filter to output a + 1 or-1 sideband optical signal as probe light according to the selected near-end measurement mode or far-end measurement mode and the target temperature of the optical adjustable filter.

The invention provides an optical feedback resonance enhanced forward Brillouin demodulation structure, which comprises a tunable laser, a first polarization controller, an erbium-doped optical fiber amplifier, an optical coupler, an optical isolator, a forward Brillouin gain optical fiber, a band-pass filter and a photoelectric detector, a second polarization controller; and a spectrum analyzer. The first polarization controller is connected with a port a of the optical coupler, a port b of the optical coupler is connected with an input end of the erbium-doped optical fiber amplifier, an output end of the erbium-doped optical fiber amplifier is connected with the optical isolator, the optical isolator is connected with the band-pass filter, the band-pass filter is connected with the forward Brillouin gain optical fiber, and the optical fiber is fed back to a port c of the coupler through the second polarization controller. The output power of the erbium-doped optical fiber amplifier is controlled, and the polarization states of the pump light and the feedback laser are controlled by the first polarization controller and the second polarization controller, so that the forward Brillouin effect is amplified.

The utility model belongs to the technical field of optical fiber lasers, and relates to a multi-wavelength random optical fiber laser based on a four-port circulator and Brillouin-Rayleigh scattering, which is a closed-loop random optical fiber laser and comprises the four-port circulator, a seed laser is connected with the first port of the four-port circulator, and a seed laser is connected with the second port of the four-port circulator. The second port is connected with the Brillouin gain optical fiber, the third port is connected with the random Rayleigh scattering optical fiber, and the fourth port is connected with the optical fiber coupler; an erbium-doped fiber and a wavelength division multiplexer are connected between the Brillouin gain fiber and the fiber coupler, and a pump light port of the wavelength division multiplexer is connected with an output port of the 980nm laser. According to the utility model, the Brillouin gain optical fiber is subjected to Brillouin scattering, and the Rayleigh scattering of the random Rayleigh scattering optical fiber and the gain amplification of the erbium-doped optical fiber are combined, so that efficient and stable multi-wavelength output is realized, the number of output wavelengths is adjustable, the stability is high, and the device is suitable for a high-precision optical fiber sensing and dense wavelength division multiplexing system.

The application provides a Brillouin frequency shift extraction method, an optical fiber sensing system, equipment and a medium, wherein the Brillouin frequency shift extraction method comprises: acquiring an original Brillouin gain spectrum; performing an iteration process until a preset iteration termination condition is met, and acquiring a Brillouin frequency shift based on a first fitting frequency shift acquired in the last iteration process; the iteration process comprises: performing enhancement processing on a main Lorentz component in the first Brillouin gain spectrum to acquire a second Brillouin gain spectrum; wherein in the first iteration process, the first Brillouin gain spectrum is the original Brillouin gain spectrum; fitting the relationship between the Brillouin frequency shift and the Brillouin gain based on a first fitting window of the second Brillouin gain spectrum to acquire a fitting result; acquiring the first fitting frequency shift based on the fitting result; and determining the second Brillouin gain spectrum as a new first Brillouin gain spectrum. The above scheme performs enhancement processing on the main Lorentz component, so that the main Lorentz component is easier to capture, and is conducive to improving the calculation accuracy of the Brillouin frequency shift.

The invention provides a method, a device and equipment for inhibiting a stimulated Brillouin effect in an optical fiber. The method for inhibiting the stimulated Brillouin effect in the optical fiber comprises the following steps: acquiring an optical fiber to be processed; drawing the to-be-processed optical fiber into an e index distribution shape according to a preset optical fiber drawing rate to obtain a drawn optical fiber; the radius of the drawn optical fiber changes periodically; the preset optical fiber drawing rate is obtained based on a substance conservation equation. According to the invention, a relay station does not need to be additionally arranged, and the problem is directly solved at the optical fiber design level, so that the communication cost for inhibiting the stimulated Brillouin scattering SBS effect is remarkably reduced; and secondly, the Brillouin gain spectrum is split into a plurality of peaks through the periodic optical fiber structure, and the Brillouin gain is dispersed, so that the threshold value of the SBS effect is improved, higher incident power is allowed, the obvious SBS effect is not caused, and the signal quality is improved.

This invention relates to the fields of optical fiber communication and microwave photonics. Existing tunable dual-passband microwave photonic filters suffer from poor passband stability and cannot meet practical application requirements. This invention provides a narrow-band tunable dual-passband microwave photonic filter using a Brillouin fiber laser. It generates dual-tone pump light to excite the Brillouin using a tunable laser source and an intensity modulator. Combined with a Brillouin fiber oscillator and a cascaded Fabry-Perot cavity, the Brillouin gain spectrum is narrowed to the kHz level. Simultaneously, the different periodic resonant frequencies of the two ring cavities effectively suppress side modes, filtering out the desired frequency band signal. Furthermore, by synchronously tuning the center frequencies of the two passbands of the filter by changing the pump light wavelength, and simultaneously controlling the output frequency of the signal generator, the frequency interval between the two passbands is changed, ultimately realizing a narrow-linewidth tunable dual-passband microwave photonic filter.

The objective of the present invention is to provide a Brillouin gain analysis device and a Brillouin gain analysis method with which it is possible for high-speed strain changes in an optical fiber to be measured distributionally.　A Brillouin gain analysis device 301 according to the present invention comprises: a laser 11 for outputting continuous light having a single frequency; a pulse generator 12 for pulsing the continuous light from the laser and inputting the same into one end of an optical fiber 50 being measured; an ASE light source 13 for generating continuous light having frequency components over a wider band than the frequency of the continuous light output by the laser 11, and inputting the same into the other end of the optical fiber 50; a modulator 14 for generating local light obtained by shifting the frequency of the continuous light from the laser 11 by an arbitrarily defined frequency; and a wave detector 15 for performing heterodyne detection between Brillouin scattered light generated by the optical fiber and the local light.

The application discloses a method for regulating Brillouin gain, a laser and an optical microwave source, and specifically relates to the method for regulating Brillouin gain. a The application discloses a method for regulating Brillouin gain, a laser and an optical microwave source, and specifically relates to the method for regulating Brillouin gain. The method for regulating Brillouin gain adopts the gradual change of the angle between the circular light path and the crystal axis, so that the speed of the generated acoustic phonon is continuously changed, and then the widened backward Brillouin gain feature is generated, the threshold of the backward Brillouin laser is reduced, the linewidth of the Brillouin laser is reduced in one step, and the diversity of the Brillouin laser application is increased.

The present invention discloses a temperature extraction method for a Brillouin optical time-domain analysis system (BOTDA) based on a nuclear extreme learning machine, comprising: using the Brillouin optical time-domain analysis system to collect Brillouin gain spectrum parameters of a test optical fiber; using the nuclear extreme learning machine to analyze the parameters collected by the Brillouin optical time-domain analysis system; using the obtained real matrix as training data for the nuclear extreme learning machine; training the nuclear extreme learning machine using the training data to extract accurate temperature information; and utilizing a faster processing speed to improve system performance. The present invention introduces a nuclear extreme learning machine algorithm to improve the temperature extraction accuracy and efficiency of the Brillouin optical time-domain analysis system, which is beneficial to the application of the Brillouin optical time-domain analysis system in actual detection.

The invention discloses a compact tunable narrow-linewidth fiber laser light source, and belongs to the field of fiber lasers. The structure comprises a Brillouin pump and a Brillouin semi-open annular random fiber cavity. The Brillouin pump adopts a tunable laser and provides pump light for the Brillouin semi-open annular random optical fiber cavity. The erbium-doped optical fiber in the cavity serves as a nonlinear Brillouin gain medium and a linear gain medium at the same time, the narrowband gain of Stokes light is achieved through the stimulated Brillouin scattering effect in the optical fiber, laser output of different wavelengths can be achieved by adjusting the wavelength of Brillouin pump light and matching the center wavelength of the tunable filter, and the laser output of different wavelengths can be achieved. Random distributed feedback is introduced through the random fiber bragg grating to form random laser oscillation, the cavity length is greatly shortened, the line width is deeply compressed, and ultra-narrow line width tunable laser output is achieved while it is guaranteed that the structure of the laser light source is compact. According to the invention, the application of the tunable narrow linewidth laser in the aspects of optical fiber communication, biomedical imaging and the like is expanded.

The invention belongs to the field of optical fiber sensing, and particularly relates to a three-layer step type optical fiber structure which has a wide bending radius sensing range and high bending sensitivity on the premise that bending loss can be resisted. By regulating and controlling the refractive index of the second layer of the fiber core, balance between low bending loss and high bending sensitivity is achieved. And meanwhile, two groups of spatially separated acoustic modes are excited under a specific refractive index condition, so that double Brillouin gain peaks can be formed. Specifically, when the refractive index of the second layer of the fiber core changes, the characteristics of optical and acoustic modes and opto-acoustic interaction are studied, and finally a W-type optical fiber structure with excellent performance is determined. The structure has a wider bending radius sensing range and higher bending sensitivity while keeping a good bending loss resistance characteristic. In a word, the optical fiber structure provided by the invention has important application value in the field of optical fiber double-physical parameter distributed sensing, and a new thought is provided for realizing high-performance Brillouin bending sensing.

The application discloses a peak searching method and system for Brillouin gain spectrum, which comprises the following steps: obtaining Brillouin curves under different swept carrier frequencies, signal conditioning of Brillouin gain spectrum at different time, and fitting and peak searching of the signal after signal conditioning. The application reduces the noise introduced by carrier drift, relative intensity disturbance and other factors through signal decomposition, filtering and reconstruction of the original Brillouin gain spectrum, improves the signal-to-noise ratio of the Brillouin gain spectrum signal, and improves the accuracy of Brillouin gain spectrum peak searching.

The application discloses a method for inhibiting stimulated Brillouin scattering of a single-frequency fiber laser gain fiber, which comprises the following steps: stripping the coating layer of the gain fiber to obtain a bare fiber, wiping the bare fiber clean, and then positioning the two ends of the bare fiber by clamping the two ends of the bare fiber with a fiber clamp; heating the bare fiber by moving step by step according to a fixed length of moving interval from one end to the other end along the axial direction of the bare fiber; and increasing one or both of the temperature and the time of heating step by step after each movement, or decreasing one or both of the temperature and the time of heating step by step. The method for inhibiting stimulated Brillouin scattering of a single-frequency fiber laser gain fiber provided by the application can adjust the gradient distribution of the doped ions in the gain fiber by controlling the heating temperature, the heating time and the heating position direction parameters in a heat diffusion manner, and can broaden the Brillouin gain spectrum in the gain fiber while keeping the highest temperature of the gain fiber basically unchanged.

The application discloses a high-Briouin gain inverted ridge type chalcogenide waveguide with an air slit and a preparation method thereof. The chalcogenide waveguide comprises a substrate layer and a waveguide layer arranged on the substrate layer. The lower surface of the waveguide layer is outwardly convex to form a ridge type part. The ridge type part of the waveguide layer is embedded in the substrate layer to form an inverted ridge type waveguide structure. The inside of the ridge type part of the waveguide layer is provided with an air slit. The application limits the distribution areas of an optical field and an acoustic field through the inverted ridge type waveguide structure, enhances the acoustic-optical field overlap, simultaneously introduces an air slit structure, causes the appearance of optical radiation force, and makes the optical radiation force strongly coupled with the acoustic field near the air slit, enhances the coupling effect of the optical force and the acoustic field in the waveguide, and thus significantly improves the stimulated Briouin scattering gain. The waveguide structure can be applied to a laser, a microwave photon filter, slow light generation and other nonlinear optical devices.

The invention relates to a Brillouin distributed optical fiber sensing demodulation method based on frequency spectrum inverse Fourier transform, and the method comprises the following steps: parameter regulation and data set construction: modulating an external physical parameter applied to a to-be-measured optical fiber, synchronously adjusting the characteristic parameters of optical sensing devices, etc. Establishing dynamic correlation between the Brillouin frequency shift and the Brillouin scattering spectrum; and generating a random phase sequence, and converting the time-frequency domain scattering spectrum into a Brillouin time domain response signal with a wide spectrum characteristic through inverse Fourier transform. According to the method, the single broadband Brillouin gain spectrum time-domain curve is directly obtained through the fixed radio frequency source frequency, the Brillouin frequency shift amount extraction is directly realized from the broadband time-domain signal by constructing the frequency shift resolving model based on the artificial neural network, and the demodulation speed and the frequency shift resolution are superior to those of a traditional method. By optimizing the computing resource configuration, the data processing efficiency is remarkably improved, and the system meets the application requirements of distributed optical fiber sensing.

The application relates to the technical field of electro-optical frequency comb generation, and discloses a super-narrow-line-width, wide-band, flexible-repetition-frequency and adjustable electro-optical comb generation system and method, which comprises a pump laser generation branch, a fiber ring cavity, and a frequency shift injection locking branch.The pump laser generation branch comprises a distributed feedback laser, a first polarization controller and a first circulator; the fiber ring cavity comprises a second circulator, a Brillouin gain fiber, a fiber delay line, a fiber coupler, a second polarization controller, an electro-optical modulator, a dispersion compensation fiber, an optical amplifier, a flat filter and an isolator; and the frequency shift injection locking branch comprises a narrow-bandwidth filter, a polarization controller and a frequency shifter.The electro-optical frequency comb generation device of the application has a novel structure, realizes super-narrow-line-width, wide-band, flexible-repetition-frequency and adjustable electro-optical comb output, solves the limitations of narrow bandwidth and wide comb line width of a traditional electro-optical frequency comb generated based on electro-optical modulation, and does not need complex active optoelectronic feedback to maintain stable operation of the system.

The embodiments of the present application provide a method, device, and storage medium for measuring optical fiber temperature and / or strain, relating to the field of distributed optical fiber technology. The method comprises: obtaining a first high-frequency optical signal and a second low-frequency optical signal at any linear modulation frequency, and converting them into a first electrical signal and a second electrical signal; determining the average of the Brillouin attenuation and gain values ​​corresponding to the first electrical signal and the second electrical signal based on the central symmetry of BGS and BLS, and determining the measurement result of the temperature and / or strain of the optical fiber to be measured based on the Brillouin frequency shift determined from all the first average values. The present application utilizes the central symmetry of BGS and BLS to convert the high-frequency optical signal and the low-frequency optical signal obtained by the original SA-BOTDA into electrical signals and then average them, thereby suppressing the phase-to-intensity noise caused by the frequency shift of the high-frequency and low-frequency optical signals affected by the laser phase noise, and reconstructing the Brillouin gain spectrum, thereby reducing the impact of the laser linewidth on the signal-to-noise ratio.

The invention relates to a distributed optical fiber sensing system, and discloses a sensing device for rapidly measuring BOTDA (Brillouin Optical Time Domain Analysis) based on chaotic light polarization orthogonal detection, which comprises a narrow linewidth laser; signals output by the narrow linewidth laser are divided into two paths, wherein one path serves as injection light to enter the chaotic light generation module to enable the chaotic light generation module to output wide-spectrum chaotic laser, and the chaotic laser serves as detection light to be connected with one end of the sensing optical fiber after sequentially passing through the optical isolator, the electro-optical modulator, the polarization maintaining optical fiber and the erbium-doped optical fiber amplifier; the other path serves as pump light and is connected with the other end of the sensing optical fiber after sequentially passing through the semiconductor optical amplifier and the first circulator; and after being transmitted to the other end of the sensing optical fiber, the polarized orthogonal detection light is output by the output end of the first circulator and is subjected to coherent detection and data processing by the coherent detection module to obtain a Brillouin gain spectrum along the sensing optical fiber. The Brillouin gain frequency-sweeping-free measurement can be realized, and the measurement speed is improved.

The invention discloses a multi-band microwave / millimeter wave signal source with dual-port output. Comprising a narrow linewidth laser, a first optical circulator, an optical fiber coupler, a first optical amplification module, a first Brillouin gain optical fiber, a first optical filter, a first optical detector, a second optical amplification module, a second optical circulator, a second Brillouin gain optical fiber, a second optical filter and a second optical detector. On the basis of stimulated Brillouin scattering in the first Brillouin gain optical fiber and the second Brillouin gain optical fiber and light amplification of the first optical amplifier and the second optical amplifier, even-order Brillouin Stokes light with the wavelength interval being two times of Brillouin frequency shift can be obtained from the upper optical branch and the lower optical branch. The two paths of even-order Brillouin Stokes light respectively pass through two optical filters with specific wavelength selection characteristics, and the required dual-wavelength Brillouin Stokes light is selected. And the two paths of dual-wavelength Brillouin Stokes light respectively enter corresponding optical detectors for photoelectric conversion, so that the output of two paths of multi-band microwave / millimeter wave signals is realized.

The invention discloses a Brillouin temperature sensing system based on a multi-core optical fiber, an analysis method, a medium, equipment and a product, and relates to the field of optical fiber sensing. The system comprises a laser unit, a signal amplification unit, a carrier suppression modulation unit, a signal source, a first beam splitter, a second beam splitter, a third beam splitter, first to Nth circulators, first to Nth couplers, first to Nth signal processing units, a multi-core fan-in and fan-out coupler, a multi-core optical fiber and a signal acquisition and processing device. The temperature analysis method comprises the following steps: processing N paths of signals acquired by a signal acquisition and processing device to obtain a Brillouin gain spectrum of N fiber cores, and determining a Brillouin frequency shift of each fiber core; and carrying out weighted average on the Brillouin frequency shifts of the N fiber cores, and obtaining the temperature according to the Brillouin frequency shifts after average processing. According to the invention, the detection precision of the temperature sensing system can be improved.

The invention belongs to the field of sensing optical fiber design, and particularly relates to a simple M-type optical fiber structure capable of achieving equal-power double Brillouin gain peaks and bending loss resistance. According to the equipower double-Brillouin gain peak design based on the M-type optical fiber, the optical fiber ring core is evolved into the round core, a plurality of strong light and sound interactions are excited, and the equipower double-Brillouin gain peak design based on the M-type optical fiber is Specifically, when a ring core is evolved into a round core, firstly, changes of the effective refractive index and the effective mode area of an optical basic mode are researched, then, acoustic frequency evolution of an acoustic mode is researched, and finally, opto-acoustic coupling is researched. According to the invention, equipower double Brillouin gain peaks are realized in the evolution process, and a simple M-type optical fiber structure is determined. In addition, the structure also has the advantage of high bending loss resistance. In a word, the simple M-type optical fiber with the equal-power double-Brillouin gain peaks, designed by the invention, has important significance in two-parameter distributed sensing for resisting bending loss.

The application relates to a distributed optical fiber sensing system and discloses a fast measurement BOTDA sensing device based on chaotic light polarization orthogonal detection, which comprises a narrow-line-width laser; signals output by the narrow-line-width laser are divided into two paths: one path is used as injection light to enter a chaotic light generation module to make the module output chaotic light with a wide spectrum, the chaotic light is used as detection light and sequentially connected with one end of a sensing optical fiber after passing through an optical isolator, an electro-optic modulator, a polarization maintaining optical fiber and an erbium-doped fiber amplifier; the other path is used as pump light and sequentially connected with the other end of the sensing optical fiber after passing through a semiconductor optical amplifier and a first circulator; after polarization orthogonal detection light is transmitted to the other end of the sensing optical fiber, the polarization orthogonal detection light is output through a first circulator output end and is coherently detected and data processed by a coherent detection module to obtain a Brillouin gain spectrum of the sensing optical fiber along a line. The application can realize Brillouin gain sweep-free measurement and improve the measurement speed.

Provided are a measurement device, etc., with which it is possible to improve convenience while simplifying device configuration.　This measurement device branches light from a laser light source into two, intensity-modulates one branched light to generate pump light that is pulsed light composed of two frequency components, shifts the frequency of the other branched light to generate probe light, multiplexes the probe light and light emitted from one end of an optical fiber to be measured when the pump light is incident from the one end of the optical fiber, detects a beat signal of the probe light and Brillouin scattered generated in a frequency band between the two frequency components, and measures strain or the temperature of the optical fiber on the basis of the detected beat signal. The interval between the two frequency components is set so that the Brillouin gain spectrum generated on the low-frequency side of the higher frequency component and the Brillouin loss spectrum generated on the high-frequency side of the lower frequency component of the two frequency components overlap on the frequency axis.