Single-ended Brillouin distributed sensor with high spatial resolution

Abstract

The invention discloses a single-ended Brillouin distributed sensor with high spatial resolution, and belongs to the technical field of distributed optical fiber sensing. The single-ended Brillouin distributed sensor with high spatial resolution comprises a laser source module used for outputting two paths of frequency conversion laser; the input end of the pulse pump light generation module is connected with the first output end of the laser source module, and the pulse pump light generation module is used for outputting pulse pump light; the input end of the detection light generation module is connected with the second output end of the laser source module, and the detection light generation module is used for outputting detection light; the sensing module, the first input end, the second input end and the output end are connected to a node unit of the sensing module, the first input end is connected with the output end of the pulse pump light generation module, and the second input end is connected with the output end of the probe light generation module and used for reflecting probe light; optical fiber sensing information is generated and output based on the pulse pump light and the reflected probe light; the input end of the receiving module is connected with the output end of the sensing module, and the receiving module is used for generating oscilloscope display information.

Description

Technical Field

[0001] This application belongs to the field of distributed optical fiber sensing technology, and particularly relates to a single-ended Brillouin distributed sensor with high spatial resolution. Background Art

[0002] The Brillouin distributed sensor is an advanced sensing technology based on the Brillouin scattering effect in optical fibers. By analyzing the characteristics of the scattered light generated by the interaction between the laser and acoustic waves during the transmission of the laser in the optical fiber, real-time monitoring of physical quantities such as continuous temperature and strain along the entire length of the optical fiber can be achieved. The Brillouin distributed sensor has been widely used in fields such as civil engineering, energy transportation, and geological disaster warning.

[0003] Currently, Brillouin distributed sensors usually require double-ended access of the sensing optical fiber. One end of the sensing optical fiber inputs pump light pulses, and the other end inputs probe light. The pump light pulses and the probe light propagate in opposite directions in the sensing optical fiber, exciting the stimulated Brillouin amplification effect. The double-ended access of the sensing optical fiber makes the structure of the Brillouin distributed sensor dispersed, and the layout scenario of the sensing optical fiber is limited. Summary of the Invention

[0004] This application aims to solve at least one of the technical problems existing in the prior art. For this reason, this application proposes a single-ended Brillouin distributed sensor with high spatial resolution, which can make the structure of the sensor more compact and broaden the layout scenario of the sensing optical fiber.

[0005] In a first aspect, this application provides a single-ended Brillouin distributed sensor with high spatial resolution, including:

[0006] A laser source module for outputting two paths of frequency-converted lasers;

[0007] A pulsed pump light generation module, the input end of which is connected to the first output end of the laser source module, for outputting pulsed pump light;

[0008] A probe light generation module, the input end of which is connected to the second output end of the laser source module, for outputting probe light;

[0009] A sensing module, the first input end, the second input end, and the output end of which are connected to its own node unit. The first input end is connected to the output end of the pulsed pump light generation module, and the second input end is connected to the output end of the probe light generation module, for reflecting the probe light and generating and outputting fiber optic sensing information based on the pulsed pump light and the reflected probe light;

[0010] A receiving module, the input end of which is connected to the output end of the sensing module, for generating oscilloscope display information.

[0011] According to the single-ended Brillouin distributed sensor of the present application, two paths of frequency-converted laser are output by a laser source module. The two paths of frequency-converted laser are respectively converted into pulsed pump light by a pulsed pump light generation module and into probe light by a probe light generation module. The probe light is input into a sensing module, reflected at the end of the sensing module. The reflected probe light meets the pulsed pump light propagating in the opposite direction in the sensing module, and stimulated Brillouin scattering occurs, generating fiber optic sensing information which is output to a receiving module through the output end of the sensing module. The two input ends and the output end of the sensing module are connected to its own node unit. One end of the sensing optical fiber is connected to this node unit, which can realize the opposite propagation and meeting of the probe light and the pulsed pump light, making the structure of the sensor more compact and broadening the layout scenarios of the sensing optical fiber.

[0012] According to an embodiment of the present application, the sensing module includes a first optical coupler, an optical fiber circulator, a sensing optical fiber, and a mirror. The first input end of the first optical coupler is connected to the output end of the pulsed pump light generation module, the second input end is connected to the output end of the probe light generation module, and the output end is connected to the input end of the optical fiber circulator. The bi-directional transmission end of the optical fiber circulator is connected to the first end of the sensing optical fiber, and the output end is connected to the input end of the receiving module. The second end of the sensing optical fiber is connected to the first end of the mirror.

[0013] According to an embodiment of the present application, the probe light generation module includes a first continuous optical amplifier and a first optical isolator connected in sequence.

[0014] According to an embodiment of the present application, the pulsed pump light generation module includes an optical pulse generator, a polarization diversity device, a pulsed optical amplifier, and a second optical isolator connected in sequence.

[0015] According to an embodiment of the present application, the optical pulse generator is used to generate the pulsed pump light with a pulse width less than 10 nanoseconds.

[0016] According to an embodiment of the present application, the polarization diversity device is a polarization scrambler or a polarization switch.

[0017] According to an embodiment of the present application, the receiving module includes a first optical bandpass filter, a second continuous optical amplifier, a second optical bandpass filter, and a photodetector connected in sequence.

[0018] According to an embodiment of the present application, the photodetector is a direct detector or a balanced detector.

[0019] According to an embodiment of the present application, the laser source module includes a frequency converter driven by a laser and a second optical coupler. The output end of the frequency converter is connected to the input end of the second optical coupler. The first output end of the second optical coupler is connected to the input end of the pulsed pump light generation module, and the second output end is connected to the input end of the probe light generation module.

[0020] According to an embodiment of the present application, the laser is a semiconductor laser, a distributed feedback laser, or a distributed Bragg reflector laser.

[0021] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. Description of the Drawings

[0022] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, where:

[0023] Figure 1 is one of the schematic structural diagrams of the single-ended Brillouin distributed sensor provided by the embodiment of the present application;

[0024] Figure 2 is the schematic structural diagram of the sensing module provided by the embodiment of the present application;

[0025] Figure 3 is the schematic structural diagram of the probe light generation module provided by the embodiment of the present application;

[0026] Figure 4 is one of the schematic structural diagrams of the pulsed pump light generation module provided by the embodiment of the present application;

[0027] Figure 5 is the second schematic structural diagram of the pulsed pump light generation module provided by the embodiment of the present application;

[0028] Figure 6 is the schematic structural diagram of the receiving module provided by the embodiment of the present application;

[0029] Figure 7 is the schematic structural diagram of the laser source module provided by the embodiment of the present application;

[0030] Figure 8 is the second schematic structural diagram of the single-ended Brillouin distributed sensor provided by the embodiment of the present application;

[0031] Figure 9 is the schematic diagram of the frequency of the frequency-converted laser changing with time provided by the embodiment of the present application;

[0032] Figure 10It is a schematic diagram showing the variation of the frequency of the probe light with time provided by an embodiment of the present application;

[0033] Figure 11 It is a schematic diagram showing the variation of the frequency of the pulsed pump light with time provided by an embodiment of the present application.

[0034] Reference numerals:

[0035] Single-ended Brillouin distributed sensor 100, laser source module 110, frequency shifter 111, laser 112,

[0036] Second optical coupler 113, sensing module 120, node unit 121, first optical coupler 121a,

[0037] Optical fiber circulator 121b, sensing optical fiber 122, mirror 123, probe light generation module 130,

[0038] First continuous optical amplifier 131, first optical isolator 132, pulsed pump light generation module 140,

[0039] Optical pulse generator 141, polarization scrambler 142, pulsed optical amplifier 143, second optical isolator 144,

[0040] Polarization switch 145, receiving module 150, first optical bandpass filter 151, second continuous optical amplifier 152,

[0041] Second optical bandpass filter 153, photodetector 154. Detailed implementation manners

[0042] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present application and should not be construed as a limitation of the present application.

[0043] Reference will be made below to Figures 1 - 11 Describe the single-ended Brillouin distributed sensor 100 with high spatial resolution according to an embodiment of the present application.

[0044] As Figure 1 shown, the single-ended Brillouin distributed sensor 100 according to an embodiment of the present application includes a laser source module 110, a pulsed pump light generation module 140, a probe light generation module 130, a sensing module 120, and a receiving module 150.

[0045] The laser source module 110 has a first output end and a second output end. The sensing module 120 has a first input end, a second input end and an output end. The input end of the pulsed pump light generating module 140 is connected to the first output end of the laser source module 110. The output end of the pulsed pump light generating module 140 is connected to the first input end of the sensing module 120. The input end of the detection light generating module 130 is connected to the second output end of the laser source module 110. The output end of the detection light generating module 130 is connected to the second input end of the sensing module 120. The output end of the sensing module 120 is connected to the input end of the receiving module 150.

[0046] Among them, the laser source module 110 is used to output two paths of frequency-converted laser. The frequency-converted laser is a laser whose frequency changes with time. The laser source module 110 may include a laser source for generating the frequency-converted laser, and directly generate the frequency-converted laser by the laser source. Or the laser source module 110 may include a device for modulating the frequency of the light wave. After generating a laser with a constant frequency by the laser source, the laser is frequency-modulated by the frequency modulation device to obtain the frequency-converted laser.

[0047] For example, as Figure 9 shown, the frequency of the frequency-converted laser output by the laser source module 110 changes periodically with time.

[0048] In this embodiment, a device such as an optical splitter or an optical coupler may be provided at the transmission end of the laser source module 110 to output the frequency-converted laser in two paths.

[0049] In this embodiment, the input end of the pulsed pump light generating module 140 is connected to the first output end of the laser source module 110 and is used to output pulsed pump light. The pulsed pump light is a laser emitted in the form of pulses at short time intervals. A device such as a pulsed light amplifier 143 may be provided in the pulsed pump light generating module 140 to convert the frequency-converted laser into pulsed pump light.

[0050] The pulse width of the pulsed pump light may be less than 10 nanoseconds.

[0051] In this embodiment, the input end of the detection light generating module 130 is connected to the second output end of the laser source module 110 and is used to output detection light. The detection light is an optical signal transmitted through an optical fiber for detecting and measuring changes in physical quantities such as temperature and strain. The detection light generating module 130 may perform processing such as amplifying the frequency-converted laser to generate the detection light.

[0052] It should be noted that the laser source module 110 generates the frequency shift required for the stimulated Brillouin scattering effect in a time-division manner to generate the frequency-converted laser. A modulator, a microwave source and a large number of polarization-maintaining devices may be omitted in the detection light generating module 130, which can reduce the complexity and cost of the Brillouin distributed sensor.

[0053] In this embodiment, the first input terminal, the second input terminal, and the output terminal of the sensing module 120 are connected to the node unit 121 of itself. The first input terminal is connected to the output terminal of the pulsed pump light generation module 140, and the second input terminal is connected to the output terminal of the probe light generation module 130, which is used to reflect the probe light and generate and output fiber optic sensing information based on the pulsed pump light and the reflected probe light.

[0054] Among them, the node unit 121 is a unit that can realize the routing and distribution of optical signals. The node unit 121 can receive the probe light and the pulsed pump light, and guide and transmit the received probe light and pulsed pump light to the corresponding connected devices.

[0055] In this embodiment, a device for reflecting light can be arranged at one end of the sensing module 120 far from the node unit 121. After the probe light enters the sensing module 120, it is transmitted. After being transmitted to the device for reflecting light, it is reflected back to the original transmission path in the sensing module 120. After corresponding frequency modulation, the pulsed pump light can meet the reflected probe light in the sensing module 120 and undergo stimulated Brillouin scattering to generate fiber optic sensing information.

[0056] Among them, the fiber optic sensing information is information reflecting changes in physical quantities such as temperature and strain in the environment. The fiber optic sensing information can be in the form of an optical signal, and the fiber optic sensing information can be carried by the probe light and transmitted through the probe light.

[0057] In this embodiment, the input terminal of the receiving module 150 is connected to the output terminal of the sensing module 120, which is used to generate oscilloscope display information. The oscilloscope display information is information reflecting changes in physical quantities such as temperature and strain in the environment displayed on the display screen of the oscilloscope.

[0058] The fiber optic sensing information is input to the receiving module 150, and the receiving module 150 performs optoelectronic conversion on the fiber optic sensing information to obtain the oscilloscope display information. It can be understood that the output terminal of the receiving module 150 can be connected to the input terminal of the oscilloscope. After the oscilloscope display information is output to the oscilloscope, it undergoes analog-to-digital conversion by the oscilloscope and enters the subsequent digital signal processor (DSP) for subsequent signal processing and other operations, and then is displayed on the display screen of the oscilloscope.

[0059] In this embodiment, the laser source module 110 outputs two paths of frequency-converted laser. One path of frequency-converted laser generates pulsed pump light through the pulsed pump light generation module 140 and is transmitted to the sensing module 120 through the first input end of the sensing module 120. The other path of frequency-converted laser generates detection light through the detection light generation module 130 and is transmitted to the sensing module 120 through the second input end of the sensing module 120. In the sensing module 120, the detection light is reflected after transmission and meets the oppositely transmitted pulsed pump light to perform stimulated Brillouin scattering, generating fiber optic sensing information. The fiber optic sensing information is transmitted to the receiving module 150 through the output end of the sensing module 120, and the receiving module 150 performs optoelectronic conversion on the fiber optic sensing information to obtain the oscilloscope display information, realizing the measurement of physical quantities such as temperature in the environment.

[0060] In the related art, Brillouin distributed sensors usually require both ends of the sensing optical fiber to be connected. One end of the sensing optical fiber inputs pulsed pump light, and the other end inputs detection light. The pulsed pump light and the detection light propagate in opposite directions in the sensing optical fiber, exciting the stimulated Brillouin amplification effect. The dual-end connection of the sensing optical fiber makes the structure of the Brillouin distributed sensor dispersed, and the layout scenario of the sensing optical fiber is limited.

[0061] According to the single-end Brillouin distributed sensor 100 provided by the embodiment of the present application, the laser source module 110 outputs two paths of frequency-converted laser. The two paths of frequency-converted laser are respectively converted into pulsed pump light through the pulsed pump light generation module 140 and converted into detection light through the detection light generation module 130. The detection light is input into the sensing module 120 and is reflected by the end of the sensing module 120. The reflected detection light meets the oppositely transmitted pulsed pump light in the sensing module 120, and stimulated Brillouin scattering occurs, generating fiber optic sensing information that is output to the receiving module 150 through the output end of the sensing module 120. The two input ends and the output end of the sensing module 120 are connected to the node unit 121 of itself. One end of the sensing optical fiber 122 is connected to the node unit 121, and the detection light and the pulsed pump light can propagate in opposite directions and meet, which can make the structure of the sensor more compact and broaden the layout scenario of the sensing optical fiber 122.

[0062] In some embodiments, as Figure 2 shown, the sensing module 120 includes a first optical coupler 121a, an optical fiber circulator 121b, a sensing optical fiber 122, and a mirror 123. The first input end of the first optical coupler 121a is connected to the output end of the pulsed pump light generation module 140, the second input end is connected to the output end of the detection light generation module 130, the output end is connected to the input end of the optical fiber circulator 121b, the bidirectional transmission end of the optical fiber circulator 121b is connected to the first end of the sensing optical fiber 122, the output end is connected to the input end of the receiving module 150, and the second end of the sensing optical fiber 122 is connected to the first end of the mirror 123.

[0063] Among them, the first optical coupler 121a may include a first input end, a second input end, and an output end. The first input end and the second input end of the first optical coupler 121a may correspond to the first input end and the second input end of the sensing module 120. The pulsed pump light is input into the first optical coupler 121a from the first input end of the first optical coupler 121a, and the probe light is input into the first optical coupler 121a from the second input end of the first optical coupler 121a. The pulsed pump light and the probe light are input into the sensing module 120 through the first optical coupler 121a.

[0064] The optical fiber circulator 121b may include an input end, a bidirectional transmission end, and an output end. The pulsed pump light and the probe light are transmitted to the optical fiber circulator 121b and transmitted to the sensing optical fiber 122 through the bidirectional transmission end of the optical fiber circulator 121b. The fiber optic sensing information generated in the sensing optical fiber 122 is then transmitted to the optical fiber circulator 121b through the bidirectional transmission end of the optical fiber circulator 121b and transmitted to the receiving module 150 through the output end of the optical fiber circulator 121b. The output end of the optical fiber circulator 121b corresponds to the output end of the sensing module 120.

[0065] It can be understood that the node unit 121 may include the first optical coupler 121a and the optical fiber circulator 121b.

[0066] The sensing optical fiber 122 is an element that can detect and measure changes in physical quantities such as temperature and strain in the environment. The sensing optical fiber 122 includes a first end and a second end. The probe light and the pulsed pump light are input into the sensing optical fiber 122 through the first end of the sensing optical fiber 122.

[0067] The mirror 123 is a device that can reflect the probe light and make the probe light return along the original transmission path in the sensing optical fiber 122. The first end of the mirror 123 is connected to the second end of the sensing optical fiber 122, that is, the mirror 123 is arranged at the end of the sensing optical fiber 122.

[0068] In this embodiment, the pulsed pump light is input into the first optical coupler 121a from the first input end of the first optical coupler 121a, and the probe light is input into the first optical coupler 121a from the second input end of the first optical coupler 121a. The pulsed pump light and the probe light are output from the output end of the first optical coupler 121a to the input end of the fiber optic circulator 121b, and are transmitted to the first end of the sensing optical fiber 122 through the bidirectional transmission end of the fiber optic circulator 121b. The probe light is transmitted in the sensing optical fiber 122 to the second end of the sensing optical fiber 122, and is reflected by the mirror 123 and returned to the first end of the sensing optical fiber 122. After corresponding frequency modulation, when the pulsed pump light is transmitted to the first end of the sensing optical fiber 122, it can meet the probe light propagating in the opposite direction, and stimulated Brillouin scattering occurs to generate fiber optic sensing information. The fiber optic sensing information is transmitted to the fiber optic circulator 121b through the bidirectional transmission end of the fiber optic circulator 121b, and is output from the output end of the fiber optic circulator 121b to the receiving module 150.

[0069] In some embodiments, as Figure 3 shown, the probe light generation module 130 includes a first continuous optical amplifier 131 and a first optical isolator 132 connected in sequence.

[0070] Among them, the first continuous optical amplifier 131 is a device for enhancing the intensity of the frequency-converted laser, and the first optical isolator 132 is an element that restricts the direction of light so that light can only be transmitted in a single direction.

[0071] In this embodiment, the frequency-converted laser is amplified in intensity by the first continuous optical amplifier 131 to obtain the probe light, and is output to the sensing module 120 through the first optical isolator 132.

[0072] In this embodiment, the laser source module 110 generates the frequency offset required for the stimulated Brillouin scattering effect in a time-sharing manner to generate the frequency-converted laser. The modulator, microwave source, and a large number of polarization-maintaining devices can be omitted in the probe light generation module 130, which can reduce the complexity and cost of the sensor.

[0073] In some embodiments, as Figure 4 and Figure 5 shown, the pulsed pump light generation module 140 includes an optical pulse generator 141, a polarization diversity device, a pulsed optical amplifier 143, and a second optical isolator 144 connected in sequence.

[0074] Among them, the optical pulse generator 141 is used to convert the frequency-converted laser into pulsed pump light. The optical pulse generator 141 can be a Mach-Zehnder modulator with a high extinction ratio, a semiconductor optical amplifier, or the like.

[0075] A polarization splitter is a component that can split an input optical signal into two or more independent optical paths according to the polarization state. A pulsed optical amplifier 143 is a device used to enhance the intensity of the pulsed pump light. A second optical isolator 144 is a component that restricts the direction of light so that light can only be transmitted in one direction.

[0076] In this embodiment, the optical pulse generator 141, the polarization splitter, the pulsed optical amplifier 143, and the second optical isolator 144 are connected in sequence. The frequency-converted laser is converted into pulsed pump light by the optical pulse generator 141. The pulsed pump light undergoes polarization splitting by the polarization splitter, and after the intensity is enhanced by the pulsed optical amplifier 143, it is output through the second optical isolator 144.

[0077] In some embodiments, the optical pulse generator 141 is used to generate pulsed pump light with a pulse width less than 10 nanoseconds.

[0078] In this embodiment, a narrow electrical pulse signal with a subsonic response time can be input to the optical pulse generator 141, and the frequency-converted laser is converted into pulsed pump light with a pulse width less than 10 nanoseconds by the optical pulse generator 141. Among them, the narrow electrical pulse signal can be in the form of a single pulse or in the form of a pulse train.

[0079] The pulsed pump light with a pulse width less than 10 nanoseconds has characteristics such as high energy density and high time resolution, and can excite a transient acoustic wave field. The transient acoustic wave field is an acoustic wave field that is generated, propagates, and changes with time in a medium within a short time.

[0080] In the related art, Brillouin distributed sensors usually operate under a steady acoustic wave field (SAW) so that the energy conversion between the pump light and the probe light is concentrated within an extremely narrow frequency range, thereby obtaining a Brillouin gain spectrum (BGS) with both a high peak gain and a narrow Brillouin linewidth, that is, the Brillouin signal carrying sensing information, so as to accurately extract the Brillouin frequency shift value (BFS) linearly related to temperature and strain through BGS fitting.

[0081] However, because there are actually various linear and non-linear adverse effects during the process of exciting the acoustic wave to a steady state, these adverse effects greatly reduce the Brillouin energy utilization efficiency, and most of the different single-performance improvement methods are contradictory in working principles and implementation methods and cannot be compatible, making it impossible for Brillouin distributed fiber optic sensors to achieve long distance, high precision, high speed, and high spatial resolution simultaneously.

[0082] In the embodiments of the present application, the pulsed pump light generation module 140 generates pulsed pump light, generates a transient acoustic wave field based on the pulsed pump light, generates fiber optic sensing information based on the pulsed pump light and the probe light under the transient acoustic wave field, and performs optoelectronic conversion on the fiber optic sensing information under the transient acoustic wave field. Under the transient acoustic wave field, the acoustic field is in the establishment process, and the amplitude of the acoustic field increases non-linearly with the increase of the interaction time between the pulsed pump light and the probe light, that is, it is manifested as a time-weighted acoustic amplitude. Since the magnitude of the energy conversion between the pulsed pump light and the probe light is linearly related to the acoustic amplitude, the time-weighted energy conversion characteristic results in most of the energy conversion being contributed by the rear part of the pulse, which makes the actual energy accumulation length lower than the pulse width. Thus, the single-ended Brillouin distributed sensor 100 can achieve a higher spatial resolution under a wide pulse, that is, a super pulse-width spatial resolution.

[0083] In addition, the single-ended Brillouin distributed sensor 100 can bypass the acoustic pre-pumping process necessary for a Brillouin sensor to achieve high spatial resolution under a steady-state acoustic wave field, thereby avoiding the adverse effects brought by this process, and can ensure the measurement distance, accuracy and speed while improving the spatial resolution.

[0084] The BGS generated by the transient acoustic wave field is extremely wide and the spectral resolution is low. Therefore, the method of extracting the BFS by fitting the gain spectrum under the steady-state acoustic wave field is no longer applicable. However, the wide BGS under the transient acoustic wave field and the narrow BGS under the steady-state acoustic wave field actually have almost the same total spectral power. Then, under the transient acoustic wave field, the energy transfer between the pulsed pump light and the probe light actually occurs in a wider frequency range. When the frequency offset between the pulsed pump light and the probe light deviates from the fiber Brillouin resonance frequency, that is, the Brillouin frequency shift, the gain value of the broadband gain spectrum brought by the transient acoustic wave field will be much higher than the gain value of the narrowband gain spectrum under the steady-state acoustic wave field, which can bring a wider effective ratio range for the Brillouin gain ratio method, thereby greatly broadening the effective gain range of the Brillouin gain ratio spectrum. The linear region of the Brillouin gain ratio spectrum can theoretically be expanded by at least 4 times, which can solve the problem that the linear region of the Brillouin gain ratio spectrum is small in conventional Brillouin Optical Time Domain Analysis (BOTDA), and the measurement is prone to distortion and is unreliable. Among them, the linear region of the Brillouin gain ratio spectrum corresponds to the measurement range.

[0085] Therefore, the single-ended Brillouin distributed sensor 100 provided by the embodiments of the present application no longer requires the gain spectrum scanning method and the gain spectrum fitting method widely used in conventional BOTDA. Among them, the measurement process of the gain spectrum scanning method is time-consuming, and the demodulation process of the gain spectrum fitting method is time-consuming. Instead, only the simple and fast two-point frequency scanning method and the Brillouin gain ratio method are needed to obtain the fiber Brillouin frequency shift distribution. Among them, the measurement process of the two-point frequency scanning method is fast, and the demodulation process of the Brillouin gain ratio method is fast, so that the overall response time of the single-ended Brillouin distributed sensor 100 can be theoretically shortened by 2-3 orders of magnitude, and large dynamic strain can be quickly and accurately responded at the second-level time granularity, thus changing the Brillouin fiber sensing measurement method from static to dynamic and making it possible to quickly detect dynamic targets.

[0086] In this embodiment, a pulsed pump light generating module 140 generates pulsed pump light, and a transient acoustic wave field is generated based on the pulsed pump light. Under the transient acoustic wave field, fiber sensing information is generated based on the pulsed pump light and the probe light. Based on the time-weighted gain evolution characteristic and the broadband energy conversion characteristic of the transient acoustic wave field, the single-ended Brillouin distributed sensor 100 can achieve higher spatial resolution under wide pulses, and can shorten the overall response duration. In addition, the acoustic pre-pumping process for the Brillouin sensor to achieve high spatial resolution under the steady-state acoustic wave field can be bypassed, so that the adverse effects brought by this process can be avoided, and the measurement distance, accuracy and speed can be ensured while improving the spatial resolution.

[0087] In some embodiments, the polarization diversity device is a polarization scrambler 142 or a polarization switch 145.

[0088] Among them, the polarization scrambler 142 is a device that can randomly change or disrupt the polarization state of the optical signal, and the polarization switch 145 is a device that can quickly switch the polarization state of the optical signal.

[0089] As Figure 4 shown, the optical pulse generator 141, the polarization scrambler 142, the pulsed optical amplifier 143 and the second optical isolator 144 are connected in sequence.

[0090] As Figure 5 shown, the optical pulse generator 141, the polarization switch 145, the pulsed optical amplifier 143 and the second optical isolator 144 are connected in sequence.

[0091] It should be noted that when the polarization diversity device is the polarization scrambler 142 or the polarization switch 145, the optical pulse generator 141 can generate pulsed pump light with a pulse width less than 10 nanoseconds to excite the transient acoustic wave field.

[0092] In the related art, under a steady-state acoustic wave field, the peak energy conversion between the pump light and the probe light is relatively high. Especially in the case of pulse coding, higher energy conversion leads to stronger optical noise. For example, polarization noise when using a polarization scrambler, backward Brillouin scattering noise related to Brillouin gain, beat frequency noise between the backward Raman-probe light, etc. The presence of this optical noise will reduce the signal-to-noise ratio and measurement accuracy.

[0093] In the embodiments of the present application, under a transient acoustic wave field, the polarization diversity method is adopted, and the peak energy conversion between the pulsed pump light and the probe light is lower, so that the optical noise related to Brillouin gain is suppressed, thereby improving the signal-to-noise ratio and measurement accuracy.

[0094] In the related art, under a steady-state acoustic wave field, the peak energy conversion between the pump light and the probe light is relatively high. Especially in the case of pulse coding, according to the polarization dragging effect, high energy conversion causes the polarization state of the probe light and the pump light to gradually deviate from the polarization direction of the pump light during the interaction process. When using the polarization diversity method through a polarization switch, after the probe light acts with the orthogonal pump lights respectively, it will deflect to two orthogonal directions, thus greatly reducing the efficiency of polarization diversity and resulting in residual polarization fading still existing after signal superposition.

[0095] In the embodiments of the present application, under a transient acoustic wave field, the peak energy conversion between the pulsed pump light and the probe light is lower. This enables the polarization state of the probe light to remain unchanged after acting with the orthogonal pulsed pump lights respectively when implementing the polarization diversity method through the polarization switch 145, thereby improving the efficiency of the polarization diversity method. The polarization fading can be effectively eliminated, and the signal-to-noise ratio and measurement accuracy can be improved.

[0096] In some embodiments, as Figure 6 shown, the receiving module 150 includes a first optical bandpass filter 151, a second continuous optical amplifier 152, a second optical bandpass filter 153, and a photodetector 154 that are connected in sequence.

[0097] Among them, the first optical bandpass filter 151 and the second optical bandpass filter 153 are devices for separating the upper sideband and the lower sideband of the optical signal, and can be an optical isolator, a dense wavelength division multiplexer. The second continuous optical amplifier 152 is a device for amplifying the intensity of the continuous light, and the photodetector 154 is a device that can measure the intensity of the optical signal and convert the optical signal into an electrical signal.

[0098] In this embodiment, after the fiber optic sensing information passes through the first optical bandpass filter 151, it is intensity-amplified by the second continuous optical amplifier 152, the upper and lower sidebands are separated by the second optical bandpass filter 153, and then input to the photodetector 154. The photodetector 154 performs photoelectric conversion on the fiber optic sensing information to obtain the information displayed on the oscilloscope.

[0099] In some embodiments, the photodetector 154 is a direct detector or a balanced detector.

[0100] Among them, the direct detector is a device that can directly measure the intensity of the optical signal and convert the optical signal into an electrical signal, and the balanced detector is a device that can convert the optical signal into an electrical signal based on the differential technology.

[0101] In this embodiment, when the photodetector 154 is a direct detector, the upper sideband and the lower sideband of the fiber optic sensing information are simultaneously transmitted to the direct detector, and the direct detector performs photoelectric conversion on the fiber optic sensing information to obtain the oscilloscope display information.

[0102] When the photodetector 154 is a balanced detector, the upper sideband and the lower sideband of the fiber optic sensing information are respectively transmitted to the two input ends of the balanced detector, and the balanced detector performs photoelectric conversion on the fiber optic sensing information to obtain the oscilloscope display information.

[0103] It should be noted that when the photodetector 154 is a direct detector or a balanced detector, the optical pulse generator 141 can generate a pulsed pump light with a pulse width less than 10 nanoseconds to excite the transient acoustic wave field.

[0104] In the related art, under the steady-state acoustic wave field, the peak gain is high. Under pulse coding, the cumulative Brillouin gain value is much higher than the absolute value of the cumulative Brillouin loss value. If balanced detection is used, decoding noise will be caused. Therefore, balanced detection is usually not used in pulse-coded Brillouin optical time domain analysis (BOTDA) to improve the signal-to-noise ratio and measurement accuracy.

[0105] In the embodiment of the present application, under the transient acoustic wave field, the peak gain is low. Even under pulse coding, the Brillouin gain value is close to the absolute value of the Brillouin loss value. Therefore, no decoding noise will be generated in the case of using balanced detection. Under transient pulse coding, balanced detection can be performed through a balanced detector, which can suppress polarization noise, common-mode noise, etc. while increasing the intensity of the sensing signal, thereby improving the signal-to-noise ratio and measurement accuracy.

[0106] It can be understood that the output end of the photodetector 154 can be connected to the data acquisition card of the oscilloscope. The data acquisition card can perform analog-to-digital conversion on the electrical signal output by the detector, and then perform signal post-processing. The signal post-processing can include signal normalization, decoding, and calculation of the Brillouin gain ratio, etc.

[0107] In some embodiments, such as Figure 7As shown in the figure, the laser source module 110 includes a frequency converter 111 driven by a laser 112 and a second optical coupler 113. The output end of the frequency converter 111 is connected to the input end of the second optical coupler 113. The first output end of the second optical coupler 113 is connected to the input end of the pulsed pump light generation module 140, and the second output end is connected to the input end of the probe light generation module 130.

[0108] Among them, the laser 112 is a device that can emit continuous laser light, and the frequency converter 111 is a device that can quickly adjust the frequency of the continuous laser light.

[0109] In this embodiment, the frequency converter 111 is driven by the laser 112. The continuous laser light emitted by the laser 112 is frequency-adjusted by the frequency converter 111 to obtain frequency-converted laser light. One path of the frequency-converted laser light is transmitted to the second optical coupler 113, and the second optical coupler 113 divides it into two paths of frequency-converted laser light. The two paths of frequency-converted laser light are respectively output from the first output end and the second output end of the second optical coupler 113. The first output end and the second output end of the second optical coupler 113 can correspond to the first output end and the second output end of the laser source module 110.

[0110] In some embodiments, the laser 112 is a semiconductor laser, a distributed feedback laser, or a distributed Bragg reflector laser.

[0111] Among them, a semiconductor laser (SL) is a laser that uses a semiconductor material as a gain medium.

[0112] A distributed feedback laser (DFB) is a device that realizes optical feedback by etching a periodic grating structure in the active layer of the laser. The distributed feedback laser can selectively amplify light of a specific wavelength to output light of a single frequency.

[0113] A distributed Bragg reflector (DBR) laser is a laser that uses a distributed Bragg reflector structure to select and stabilize the laser output wavelength.

[0114] In the embodiments of the present application, the single-ended Brillouin distributed sensor 100 can be divided into the following functional parts:

[0115] 1. Transmitter: It may include a laser source module 110, a pulsed pump light generation module 140, and a probe light generation module 130. The transmitter is used to construct a pulsed pump light with high robustness against parasitic adverse effects and an orthogonally polarized dual-tone probe light with high suppression of polarization noise to extend the sensing distance. Among them, the pump pulse width of the pulsed pump light is less than 10 nanoseconds to excite a transient acoustic wave field. The pulse coding sequence of the subsonic response time can be generated by cascaded lasers 112, semiconductor optical amplifiers, and electrical signal generators.

[0116] In this embodiment, the broadband Brillouin gain characteristic of the transient acoustic wave field enables it to have more uniform and gentle pump-probe light energy conversion in a wider frequency range. The broadband energy conversion characteristic of the transient acoustic wave field forms a complementary relationship with the optical pulse coding, that is, the low peak Brillouin gain of the transient acoustic wave field can effectively suppress the high gain accumulation and strong adverse effects of the pulse coding, enabling the pulse coding length to be significantly increased to improve the signal-to-noise ratio and extend the sensing distance.

[0117] At the same time, the low peak Brillouin gain characteristic of the transient acoustic wave field makes the cumulative Brillouin gain of the pulse coding in the Stokes component of the probe light and the cumulative Brillouin loss in the anti-Stokes component of the probe light have similar absolute gain / loss values. Therefore, the probe light with Stokes and anti-Stokes components orthogonal to each other is combined with a polarization-scrambled pump light to suppress polarization noise. It should be noted that in the pulsed coding pump light scheme under the transient acoustic wave field, the combination of the orthogonally polarized dual-tone probe light and the polarization-scrambled pump light can correctly decode the single-pulse response.

[0118] Through the pump light pulse coding sequence and the orthogonally polarized dual-tone probe light with the subsonic response time of the transmitter, the signal-to-noise ratio can be greatly improved, thereby extending the sensing distance.

[0119] 2. Transmission link: It may include a sensing module 120 to achieve fine detection of the target to be measured with a high spatial resolution of an ultra-wide pulse width.

[0120] In related technologies, distributed Brillouin optical fiber sensing is based on a steady-state acoustic wave field. In the steady-state acoustic wave state, the generation of new phonons and the annihilation of old phonons form a dynamic balance. Therefore, the acoustic wave amplitude no longer changes with the pump-probe light interaction time, that is, an invariant acoustic wave amplitude, making the spatial resolution directly determined by the pulse width. For example, when the pulse width is 10 ns, the spatial resolution is 1 meter.

[0121] In the embodiments of the present application, based on the transient acoustic wave field, when the acoustic wave field is in the establishment process under the transient acoustic wave field, the amplitude of the acoustic wave field increases non-linearly with the increase of the interaction time of the pump light and the probe light, that is, the time-weighted acoustic wave amplitude. Since the magnitude of the energy conversion between the pump light and the probe light is linearly related to the acoustic wave amplitude, the time-weighted energy conversion characteristic results in that most of the energy conversion is contributed by the rear part of the pulse, which makes the actual energy accumulation length shorter than the pulse width. Thus, the single-ended Brillouin distributed sensor 100 can achieve a higher spatial resolution under a wide pulse, that is, a super pulse-width spatial resolution. In addition, the single-ended Brillouin distributed sensor 100 can bypass the acoustic wave pre-pumping process necessary for the Brillouin sensor to achieve a high spatial resolution under the steady-state acoustic wave field, thereby avoiding the adverse effects brought by this process, and can ensure the measurement distance, accuracy and speed while improving the spatial resolution.

[0122] III. The receiving end may include a receiving module 150 to construct a broadband Brillouin gain ratio method to achieve high-time-resolution sensing.

[0123] In the related art, distributed Brillouin optical fiber sensing usually reconstructs the distribution of the Brillouin Gain Spectrum (BGS) by multi-point frequency sweeping, and then extracts the distribution of the Brillouin Frequency Shift (BFS) by the gain spectrum fitting method. The process of BGS measurement and demodulation is time-consuming, which limits the time resolution of Brillouin sensing, that is, the sensing speed, making it difficult to respond to high-speed dynamic targets in a timely manner.

[0124] In the embodiments of the present application, the BGS generated by the transient acoustic wave field is extremely wide and the spectral resolution is low. Therefore, the method of extracting the BFS by the gain spectrum fitting method under the steady-state acoustic wave field is no longer applicable. However, the wide BGS under the transient acoustic wave field and the narrow BGS under the steady-state acoustic wave field actually have almost the same total spectral power. Then, under the transient acoustic wave field, the energy transfer between the pulsed pump light and the probe light actually occurs in a wider frequency range. When the frequency offset between the pulsed pump light and the probe light deviates from the fiber Brillouin resonance frequency, that is, the Brillouin frequency shift, the gain value of the broadband gain spectrum brought by the transient acoustic wave field will be much higher than the gain value of the narrowband gain spectrum under the steady-state acoustic wave field, which can bring a wider effective ratio range for the Brillouin gain ratio method, thereby greatly broadening the effective gain range of the Brillouin gain ratio spectrum. The linear region of the Brillouin gain ratio spectrum can theoretically be expanded by at least 4 times, which can solve the problem that the linear region of the Brillouin gain ratio spectrum is small in the conventional BOTDA, and the measurement is prone to distortion and unreliable. Among them, the linear region of the Brillouin gain ratio spectrum corresponds to the measurement range.

[0125] Therefore, the single-ended Brillouin distributed sensor 100 provided by the embodiments of the present application no longer requires the gain spectrum scanning method and the gain spectrum fitting method widely used in conventional Brillouin optical time domain analysis (BOTDA). Among them, the measurement process of the gain spectrum scanning method is time-consuming, and the demodulation process of the gain spectrum fitting method is time-consuming. Instead, only the simple and fast two-point frequency scanning method and the Brillouin gain ratio method are needed to obtain the fiber Brillouin frequency shift distribution. Among them, the measurement process of the two-point frequency scanning method is fast, and the demodulation process of the Brillouin gain ratio method is fast, so that the overall response time of the single-ended Brillouin distributed sensor 100 can be theoretically shortened by 2-3 orders of magnitude, and large dynamic strain can be quickly and accurately responded at the second-level time granularity, thus changing the Brillouin fiber sensing measurement method from static to dynamic and making it possible to quickly detect dynamic targets.

[0126] The single-ended Brillouin distributed sensor 100 provided by the embodiments of the present application starts from the intrinsic physical properties of the transient acoustic wave field and can realize the synchronous improvement of the sensing distance, spatial resolution, time resolution and measurement accuracy through a collaborative and complementary system architecture composed of a transmitting end, a transmission link and a receiving end. Among them, the sensing distance is determined by the signal-to-noise ratio.

[0127] The following introduces a specific embodiment of a single-ended Brillouin distributed sensor 100.

[0128] As Figure 8 shown, the output end of the frequency converter 111 driven by the laser 112 is connected to the input end of the second optical coupler 113.

[0129] The first output end of the second optical coupler 113 is connected to the input end of the optical pulse generator 141. The optical pulse generator 141 is driven by an electrical pulse signal. The output end of the optical pulse generator 141 is connected to the input end of the polarization switch 145. The output end of the polarization switch 145 is connected to the input end of the pulsed optical amplifier 143. The output end of the pulsed optical amplifier 143 is connected to the input end of the second optical isolator 144. The output end of the second optical isolator 144 is connected to the first input end of the first optical coupler 121a.

[0130] The second output end of the second optical coupler 113 is connected to the input end of the first continuous optical amplifier 131. The output end of the first continuous optical amplifier 131 is connected to the input end of the first optical isolator 132. The output end of the first optical isolator 132 is connected to the second input end of the first optical coupler 121a.

[0131] The output end of the first optical coupler 121a is connected to the input end of the optical fiber circulator 121b. The bidirectional transmission end of the optical fiber circulator 121b is connected to the first end of the sensing optical fiber 122. The second end of the sensing optical fiber 122 is connected to the first end of the mirror 123.

[0132] The output end of the optical fiber circulator 121b is connected to the input end of the first optical band-pass filter 151. The output end of the first optical band-pass filter 151 is connected to the input end of the second continuous optical amplifier 152. The output end of the second continuous optical amplifier 152 is connected to the input end of the second optical band-pass filter 153. The output end of the second optical band-pass filter 153 is connected to the photodetector 154.

[0133] The acousto-optic frequency shifter 111 is driven by the laser 112. The continuous laser emitted by the laser 112 is frequency-adjusted by the acousto-optic frequency shifter 111 to obtain frequency-converted laser light. The frequency-converted laser light is transmitted to the second optical coupler 113 and is split into two paths of frequency-converted laser light by the second optical coupler 113. The two paths of frequency-converted laser light are respectively transmitted to the optical pulse generator 141 and the first continuous optical amplifier 131.

[0134] One path of frequency-converted laser light is converted into pulsed pump light with a pulse width less than 10 nanoseconds by the optical pulse generator 141. The pulsed pump light is subjected to polarization diversity by the polarization switch 145 and is intensity-enhanced by the pulsed optical amplifier 143, and then is output to the first optical coupler 121a through the second optical isolator 144.

[0135] The other path of frequency-converted laser light is amplified in intensity by the first continuous optical amplifier 131 to obtain probe light, and is output to the first optical coupler 121a through the first optical isolator 132.

[0136] The pulsed pump light and the probe light are output from the output end of the first optical coupler 121a to the input end of the optical fiber circulator 121b, and are transmitted to the first end of the sensing optical fiber 122 by the bidirectional transmission end of the optical fiber circulator 121b. The probe light is transmitted in the sensing optical fiber 122 to the second end of the sensing optical fiber 122, is reflected by the mirror 123, and returns to the first end of the sensing optical fiber 122. After corresponding frequency modulation, when the pulsed pump light is transmitted to the first end of the sensing optical fiber 122, it can meet the probe light propagating in the opposite direction, and stimulated Brillouin scattering occurs to generate fiber optic sensing information. The fiber optic sensing information is transmitted to the optical fiber circulator 121b by the bidirectional transmission end of the optical fiber circulator 121b, and is output from the output end of the optical fiber circulator 121b to the first optical band-pass filter 151.

[0137] After passing through the first optical band-pass filter 151, the fiber optic sensing information is intensity-amplified by the second continuous optical amplifier 152, the upper and lower sidebands are separated by the second optical band-pass filter 153, and are input to the photodetector 154. The photodetector 154 performs optoelectronic conversion on the fiber optic sensing information to obtain the information displayed on the oscilloscope.

[0138] In this embodiment, the acousto-optic frequency shifter 111 driven by the laser 112 generates the frequency shift required for stimulated Brillouin scattering in a time-sharing manner to obtain frequency-converted laser light. The time-frequency relationship of the frequency-converted laser light is as Figure 9 shown, thereby omitting the modulator, microwave source, and a large number of polarization-maintaining devices, reducing the system complexity and cost.

[0139] The relationship between the frequency of the frequency-converted laser light and time is as Figure 9 shown. After the frequency-converted laser light is emitted, it is split into two paths by the second optical coupler 113. One path of the frequency-converted laser light is amplified in intensity by the first continuous optical amplifier 131 to obtain the probe light. The relationship between the frequency of the probe light and time is as Figure 10 shown. The other path of the frequency-converted laser light selects the pump light pulse part with a frequency of f0 + 10.9 GHz and a width of the subsonic response time through the optical pulse generator 141 to obtain the pulsed pump light. The relationship between the frequency of the pulsed pump light and time is as Figure 11 shown.

[0140] Figure 9 , Figure 10 and Figure 11 where L is the length of the sensing optical fiber 122, n is the refractive index of the sensing optical fiber 122, and c is the speed of light.

[0141] The pulsed pump light and the probe light are combined by the first optical coupler 121a and then injected into the sensing optical fiber 122 through the optical fiber circulator 121b. A reflector 123 is provided at the second end of the sensing optical fiber 122. The f0 frequency part of the probe light returns to the first end of the sensing optical fiber 122 after round-trip transmission through the sensing optical fiber 122. At this time, the pulsed pump light with a frequency of f0 + 10.9 GHz is just injected into the sensing optical fiber 122 and undergoes stimulated Brillouin scattering with the probe light propagating in the opposite direction, thereby realizing distributed optical fiber sensing.

[0142] In this embodiment, the single-ended Brillouin distributed sensor 100 can simplify and single-end the sensing system while maintaining the basic performance of the metastable acoustic wavelength, improving the practicality of the sensing system.

[0143] In this embodiment, the frequency tuning accuracy is about 1 MHz, and the linewidth is less than 1 MHz.

[0144] The terms "first", "second", etc. in the description and claims of this application are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of this application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same category, and do not limit the number of objects. For example, the first object can be one or more. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / ", generally represents an "or" relationship between the associated objects before and after.

[0145] In the description of this application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of this application.

[0146] In the description of this application, the "first feature" and "second feature" may include one or more of such features.

[0147] In the description of this application, the meaning of "a plurality" is two or more.

[0148] In the description of this application, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween.

[0149] In the description of this application, the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature.

[0150] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0151] Although embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application. The scope of the present application is defined by the claims and their equivalents.

Claims

1. A single-ended Brillouin distributed sensor with high spatial resolution, characterized in that, Comprising: A laser source module for outputting two paths of frequency-converted lasers; A pulsed pump light generation module, with its input end connected to the first output end of the laser source module, for outputting pulsed pump light; A probe light generation module, with its input end connected to the second output end of the laser source module, for outputting probe light; A sensing module, with its first input end, second input end, and output end connected to its own node unit. The first input end is connected to the output end of the pulsed pump light generation module, the second input end is connected to the output end of the probe light generation module, for reflecting the probe light, and generating and outputting fiber optic sensing information based on the pulsed pump light and the reflected probe light; A receiving module, with its input end connected to the output end of the sensing module, for generating oscilloscope display information.

2. The single-ended Brillouin distributed sensor with high spatial resolution according to claim 1, characterized in that, The sensing module includes a first optical coupler, an optical fiber circulator, a sensing optical fiber, and a mirror. The first input end of the first optical coupler is connected to the output end of the pulsed pump light generation module, the second input end is connected to the output end of the probe light generation module, the output end is connected to the input end of the optical fiber circulator. The bi-directional transmission end of the optical fiber circulator is connected to the first end of the sensing optical fiber, and the output end is connected to the input end of the receiving module. The second end of the sensing optical fiber is connected to the first end of the mirror.

3. The single-ended Brillouin distributed sensor with high spatial resolution according to claim 1, characterized in that, The probe light generation module includes a first continuous optical amplifier and a first optical isolator connected in sequence.

4. The high spatial resolution single-ended Brillouin distributed sensor according to any one of claims 1-3, characterized in that, The pulsed pump light generation module includes an optical pulse generator, a polarization diversity device, a pulsed optical amplifier, and a second optical isolator connected in sequence.

5. The single-ended Brillouin distributed sensor with high spatial resolution according to claim 4, characterized in that, The optical pulse generator is used to generate the pulsed pump light with a pulse width less than 10 nanoseconds.

6. The single-ended Brillouin distributed sensor with high spatial resolution according to claim 4, characterized in that, The polarization diversity device is a polarization scrambler or a polarization switch.

7. The single-ended Brillouin distributed sensor with high spatial resolution according to any one of claims 1-3, characterized in that, The receiving module includes a first optical bandpass filter, a second continuous optical amplifier, a second optical bandpass filter, and a photodetector connected in sequence.

8. The single-ended Brillouin distributed sensor with high spatial resolution according to claim 7, characterized in that, The photodetector is a direct detector or a balanced detector.

9. The high-spatial-resolution single-ended Brillouin distributed sensor according to any one of claims 1-3, characterized in that The laser source module includes a frequency converter driven by a laser and a second optical coupler. The output end of the frequency converter is connected to the input end of the second optical coupler. The first output end of the second optical coupler is connected to the input end of the pulsed pump light generation module, and the second output end is connected to the input end of the probe light generation module.

10. The single-ended Brillouin distributed sensor with high spatial resolution according to claim 9, characterized in that The laser is a semiconductor laser, a distributed feedback laser, or a distributed Bragg reflector laser.

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