39 results about "Brillouin gain" patented technology

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.

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 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 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 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 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 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.

The application discloses a BOTDR temperature error estimation method. In a BOTDR system, the Brillouin frequency shift of the Brillouin spectrum signal is extracted by quadratic polynomial fitting, and the fiber temperature is calculated accordingly. The method is to calculate the standard deviation of the fiber temperature caused by noise according to the formula, and the measurement error of the fiber temperature is represented by the standard deviation. In the formula, σ T is the standard deviation of the fiber temperature; N is the number of sampling points; δ is the sweep interval; SNR A is the ratio of the Brillouin gain peak value to the standard deviation of the noise obeying the normal distribution; C vT is the temperature coefficient of the Brillouin frequency shift change; Δη is the difference between the maximum and minimum values of the quadratic polynomial curve obtained by fitting the normalized Brillouin spectrum in the sweep range, wherein the normalization means that the maximum value of the original signal is scaled to 1. The above parameters are known quantities except Δη, which is obtained according to the sweep range and the Brillouin shape interpolation. The accuracy of the method of the application is better than that of the existing typical method.

The invention relates to a microwave frequency testing technology, and aims to solve the problems that an existing microwave frequency measuring method based on Brillouin scattering is limited by the Brillouin gain spectrum width, and the frequency measuring resolution is difficult to improve; the invention discloses a high-resolution microwave frequency measurement technology based on a tunable Brillouin fiber laser, and the technology comprises the steps: outputting two narrow-linewidth optical carriers through a laser source, enabling an unknown signal of an upper branch to serve as pump light to excite Brillouin after intensity modulation, enabling a signal outputted by a vector network analyzer of a lower branch to serve as probe light after modulation, and enabling the probe light to serve as the probe light after intensity modulation. The probe light is selectively amplified after interacting with the Brillouin gain, an electric delay line is introduced into the Brillouin resonant cavity, and stepping tuning of the laser frequency is realized by changing the voltage applied to a medium on the electric delay line, so that a to-be-measured frequency signal is measured at high resolution; while the broadband frequency measurement range is maintained, the frequency resolution of 100 kHz is achieved, and the application potential in the fields of high-resolution radar signal detection and the like is shown.

The invention discloses a demultiplexing comb-shaped Brillouin light source generating device for spectrum synthesis, which comprises a laser generator, a high-nonlinearity optical fiber and a demultiplexing grating, and is characterized in that the laser generator is used for modulating and generating first pumping comb-shaped laser and first signal comb-shaped laser, the high-nonlinearity optical fiber is connected with the laser generator, and the demultiplexing grating is connected with the high-nonlinearity optical fiber; the first pumping comb-shaped laser and the first signal comb-shaped laser are used for reversely transmitting the first pumping comb-shaped laser and the first signal comb-shaped laser, so that the first pumping comb-shaped laser and the first signal comb-shaped laser form comb-shaped Brillouin laser with a preset frequency under the action of stimulated Brillouin gain, and the demultiplexing grating is used for separating the comb-shaped Brillouin laser with the preset frequency into a preset frequency spectral line. According to the invention, by adjusting the frequency interval difference between the first pumping comb laser and the first signal comb laser, under the action of the spectrum vernier effect, the asynchronous light field can be used for driving and generating the comb Brillouin laser with the adjustable frequency interval.

A measurement device includes a splitter splitting light from a light source into first and second lights; an optical frequency shifter shifting a frequency of the first light; a first optical modulator modulating intensity of the first light and generating probe light having two frequency components; a second optical modulator generating pump light by pulsing the second light; an optical detector detecting, when the probe light is incident from a first end of an optical fiber to be measured and the pump light is incident from a second side of the optical fiber, light emitted from the second side of the optical fiber; and a processor measuring, based on detected light intensity, temperature or distortion of the optical fiber, in which a frequency of a lower one of the two frequency components yields Brillouin gain, and a frequency of a higher frequency component yields Brillouin loss.

The invention discloses a confidential optical fiber communication encryption method and system for a physical layer, and relates to the technical field of information security, the system comprises an optical signal input / output interface, a protocol control information sorting unit, an optical domain separation encryption module and the like, and the modules cooperate to realize optical signal encryption, protocol compatibility and network management parameter acquisition. The method has the advantages that by adopting a secret key generation technology based on stimulated Brillouin scattering spectrum shape change, the system acquires physical characteristic parameters of a Brillouin gain spectrum in an optical fiber link in real time by using a secret key management module, and generates a chaotic sequence secret key of which the secret key space is not less than 2128 through Hash operation; according to the method and the system, the key is dynamically updated through the out-of-band key negotiation channel, the defects that in existing physical layer encryption, the randomness of the key is insufficient, and transmission is prone to eavesdropping are overcome, the encryption strength is improved, meanwhile, seamless switching in the key updating process is achieved, and the quantum attack resistance and long-term communication safety of the system are enhanced.

The application discloses a kind of based on ANN algorithm's optical fiber Brillouin distributed temperature, strain decoupling device and method, it is related to optical technology field.The technical points of the present application include: propose a kind of optical fiber Brillouin distributed temperature, strain decoupling device, fusion OTDR and BOTDR technology, OTDR is used to correct the local position loss distortion of sensing optical fiber in the long-term work process of BOTDR, temperature, strain, attenuation data can be measured simultaneously;Based on the above device, a kind of temperature, strain decoupling method based on ANN algorithm is proposed, the data acquisition module of fusion OTDR and BOTDR is used to collect the Brillouin gain spectrum of the optical fiber to be measured;The data fitting of the Brillouin gain spectrum of the optical fiber to be measured is carried out using Lorentz fitting algorithm, the corresponding Brillouin center frequency shift, spectrum width and amplitude are obtained, and input into the pre-trained detection model based on ANN algorithm to obtain the temperature and strain value of the optical fiber to be measured;The method effectively improves the measurement accuracy and monitoring efficiency of optical fiber sensing without increasing hardware cost.

This invention belongs to the field of distributed fiber optic sensing technology, specifically relating to a BOCDA fiber optic sensing device and method based on linearly frequency-modulated pulse pumping. The device includes a laser, fiber coupler, first electro-optic phase modulator, first erbium-doped fiber amplifier, optical isolator, sensing fiber, second electro-optic phase modulator, electro-optic intensity modulator, electro-optic pulse signal modulator, polarization scrambler, second erbium-doped fiber amplifier, optical circulator, optical filter, photodetector, low-pass filter, and data acquisition and analysis system. Because the pump light pulse frequency changes linearly, the change in probe light amplitude over time directly carries Brillouin gain spectrum information, thus avoiding scanning the pump-probe light frequency difference. Therefore, only a one-dimensional scan is needed to complete a measurement, significantly shortening the measurement time of the BOCDA fiber optic sensor.

The application discloses a Brillouin gain assisted on-chip erbium-doped laser, which comprises a micro-ring resonator, a first tapered waveguide, a second tapered waveguide and a spiral waveguide, wherein the micro-ring resonator and the first tapered waveguide are made of an erbium-doped silicon nitride waveguide, and the second tapered waveguide and the spiral waveguide are made of a chalcogenide material; the micro-ring resonator comprises a coupling waveguide which is used for coupling pump light emitted by an erbium-doped laser into the micro-ring resonator, outputting laser signals generated after the pump light is coupled into the micro-ring resonator and sequentially passing through the first tapered waveguide, the second tapered waveguide and the spiral waveguide, and outputting amplified laser signals; and the tip of the first tapered waveguide is coupled and connected with the tip of the second tapered waveguide. The application realizes high-output-power laser signals by using a composite device composed of a cascaded micro-ring resonator of an erbium-doped silicon nitride and a waveguide of a passive chalcogenide material.

The invention discloses a temperature or strain error estimation method for a Brillouin optical time domain reflectometer (BOTDR) or a Brillouin optical time domain analysis (BOTDA), which is used for a scene with high spatial resolution, and relates to a method for estimating the temperature or strain error of the Brillouin optical time domain reflectometer (BOTDR) or the Brillouin optical time domain analysis (BOTDA) of the Brillouin optical time domain reflectometer (BOTDR) or the Brillouin optical time domain analysis (BOTDA). For a high-spatial-resolution scene, linear processing is carried out on a residual error through first-order Taylor expansion, and a Gauss-Newton regular equation of a Gauss spectrum fitting method is obtained through derivation. Furthermore, the covariance among the parameters to be fitted is calculated, and a Brillouin frequency shift (BFS) error estimation formula under the high spatial resolution is obtained through derivation for the first time. Based on the formula, the BFS error can be estimated when the Brillouin line width, the Brillouin gain peak value, the frequency sweeping interval, the frequency sweeping point number, the noise standard deviation and the noise level are known, and then the temperature or strain error of the BOTDR or the BOTDA can be conveniently estimated. According to the method, the blank of temperature or strain error estimation of the BOTDR or the BOTDA under the high spatial resolution is filled up, and a reference value is provided for improvement of the precision of the BOTDR or the BOTDA.

The invention belongs to the technical field of distributed optical fiber sensing, and particularly relates to a BOCDA optical fiber sensing device and method based on linear frequency modulation pulse pumping. Comprising a laser, an optical fiber coupler, a first electro-optic phase modulator, a first erbium-doped optical fiber amplifier, an optical isolator, a sensing optical fiber, a second electro-optic phase modulator, an electro-optic intensity modulator, an electro-optic pulse signal modulator, a scrambler, a second erbium-doped optical fiber amplifier, an optical circulator, an optical filter, a photoelectric detector and a low-pass filter. And a data acquisition and analysis system. Due to the fact that the frequency of the pump light pulse changes linearly, the change of the probe light amplitude along with time directly carries Brillouin gain spectrum information, scanning of the frequency difference of the pump probe light is avoided, one-time measurement can be completed only through one-dimension scanning, and the measurement time of the BOCDA optical fiber sensor is greatly shortened.

The application provides a high spatial resolution Brillouin strain sensing measurement method and relates to the technical field of optical fiber communication.The technical points of the application include that the application reconstructs a more sharpened and clear Brillouin gain spectrum distribution by using Brillouin information in the time domain without increasing the hardware facilities of the Brillouin optical time domain analysis (BOTDA) system, and then performs self-averaging denoising on the reconstructed Brillouin gain spectrum distribution by using frequency domain information, so as to improve the signal-to-noise ratio; then the center frequency of each Brillouin gain spectrum, i.e., the distributed Brillouin frequency shift, is obtained by curve fitting on the distributed Brillouin gain spectrum, and then the strain amount is obtained according to the Brillouin frequency shift.The application enhances the spatial resolution of the BOTDA, effectively reduces the fitting error of the Brillouin frequency shift, and further improves the measurement accuracy of the optical fiber strain amount.

The application provides a non-symmetrical stress field distribution sensing method based on Brillouin polarization double-peak separation. The steps are as follows: a Brillouin optical time domain analysis system is used to collect distributed Brillouin spectrum along an optical fiber, and the Brillouin gain spectrum of each spatial resolution unit is obtained; in each spatial resolution unit, whether the Brillouin gain spectrum presents a double-peak structure is detected; for the spatial resolution unit in which the double-peak structure is detected, the spectral components corresponding to two polarization states are separated based on a physical constraint condition, and the center frequencies of the low-frequency peak and the high-frequency peak are extracted respectively; the frequency difference of the two peaks is calculated, and the non-symmetrical stress relative change of the position where the optical fiber is located in the spatial resolution unit is inversed based on the physical mapping relationship between the non-symmetrical stress relative change and the non-symmetrical stress. The application expands the traditional strain / temperature measurement to multi-dimensional mechanical state sensing, and is suitable for multiple mechanical scenes of non-symmetrical deformation of the optical fiber section.

The application discloses a signal processing method of a Brillouin optical time domain analysis system, and comprises the following steps: S1, collecting a Brillouin gain spectrum, performing two-dimensional variation modal decomposition and reconstruction; S2, performing spectrum type correction through time slot difference, and correcting the distorted Brillouin gain spectrum into a Lorentz spectrum type; and S3, extracting temperature information from the corrected Brillouin gain spectrum based on a data model. The three functions of noise reduction, spectrum type correction and temperature information extraction are realized, and the shortcomings of poor measurement accuracy and long processing time of a traditional fitting algorithm are overcome.

This invention discloses a method and apparatus for temperature extraction from a distributed Brillouin fiber optic sensor based on DeepLabv3+, relating to the field of distributed fiber optic sensing technology. The method includes: generating Brillouin gain spectrum images under different temperature, linewidth, and noise conditions through simulation, and labeling each image with a corresponding temperature tag to form a training dataset; normalizing the Brillouin gain spectrum images and standardizing the temperature tags; employing an encoder-decoder structure in the DeepLabv3+ network model, where the encoder includes a hole-space pyramid pooling module, and the decoder is used for feature fusion and upsampling; supervising the training dataset to train the DeepLabv3+ network model, optimizing network parameters, and establishing a mapping relationship between the Brillouin gain spectrum image and temperature distribution, so as to obtain the temperature distribution along the fiber optic line through the trained network model. This invention can accurately and quickly extract temperature information from BOTDA measurement data.

An apparatus for optic fiber measurement based on Brillouin optical correlation domain analysis using pulse waveform control of bits is disclosed, the apparatus including a PRBS generation unit generating electrical two identical electrical pulse pattern signals so that a probe optical signal and a pump optical signal have a time difference, and generating a first PRBS signal and a second PRBS signal by distorting a per-bit pulse waveform of each two pulse pattern signals; a probe phase modulation unit performing phase modulation of the probe optical signal according to the first PRBS signal; a pump phase modulation unit performing phase modulation of the pump optical signal according to the second PRBS signal; and a BOCDA sensor unit measuring Brillouin gain spectrum by inputting the probe optical signal and the pump optical signal with the time difference to both ends of a sensing optical fiber.