Space electric field detection optical fiber sensor

Abstract

The invention discloses a space electric field detection optical fiber sensor, and belongs to the technical field of optical fiber sensing. Comprising a round cap, a three-dimensional support, a light source, an acousto-optic modulator, an amplifier, a beam splitter and a detection assembly. According to the invention, the weak magnetic field change can be rapidly and accurately detected, and the sensitivity of magnetic field change detection is remarkably improved. The magnetostrictive optical fiber can still work reliably in a complex environment, adopts the structure that the positive magnetostrictive material layers and the negative magnetostrictive material layers are arranged on the outer layer of the optical fiber cladding in an alternate arrangement mode, can effectively restrain the mode hopping phenomenon, improves the signal-to-noise ratio of light, is easy to achieve consistency, and is free of electromagnetic radiation on the whole. The sensor is simple and easy to implement, high in reliability and accurate in positioning, real-time accurate monitoring of a weak magnetic field can be achieved, the sensor is arranged in parallel with the magnetostrictive material in a mode that the arrangement sequence of the sensor is staggered with the arrangement sequence of the magnetostrictive material, the stability of the sensor is greatly improved, and three-dimensional orientation dead-corner-free monitoring is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of fiber optic sensing, and particularly relates to a method for a spatial electric field detection fiber optic sensor. Background Art

[0002] Electric field activities pose a significant threat to fields such as power systems, aviation, and communications. Therefore, there is an urgent need for high-precision and high-reliability electric field detection technologies.

[0003] Existing electric field detection technologies mainly rely on methods corresponding to electromagnetic fields, optics, and acoustics, but all have limitations. Electromagnetic field detection uses sensors and antenna arrays to capture electromagnetic pulses, with a wide coverage range, but it is vulnerable to environmental electromagnetic noise (such as interference from power lines and communication equipment), as well as terrain and atmospheric attenuation, resulting in low positioning accuracy and high equipment costs. Optical detection records light radiation through high-speed cameras and optoelectronic sensors, with the advantages of non-contact and high resolution, but it is limited by weather (haze, rainfall) and lighting conditions, with poor performance at night, expensive equipment, and complex data processing. Acoustic detection relies on microphone arrays to capture acoustic wave signals, which can supplement acoustic characteristics, but there are problems such as signal delay, environmental noise interference (wind noise, industrial noise), and high deployment costs.

[0004] Fiber optic sensing technology has become an important supplementary means for electric field detection due to its advantages such as electromagnetic interference resistance, corrosion resistance, and high sensitivity. It detects environmental parameters such as magnetic fields by detecting changes in optical signals. Sensors based on the magnetostrictive effect can utilize the deformation of materials in a magnetic field to change the transmission characteristics of optical fibers, achieving highly sensitive detection. However, traditional fiber optic sensors have limitations such as insufficient sensitivity (especially for weak / long-distance signals), complex manufacturing processes, high costs, and slow response speeds, which restrict their large-scale application and real-time monitoring capabilities.

[0005] Therefore, there is an urgent need in the prior art for a technology to solve the above problems. Summary of the Invention

[0006] The technical problem to be solved by the present invention is: to provide a device and system for the problems existing in the background art.

[0007] A spatial electric field detection fiber optic sensor, characterized in that it includes: a round cap shell, a three-dimensional bracket, a light source, an acousto-optic modulator, an amplifier, a beam splitter, and a detection assembly;

[0008] The round cap shell is provided with a three-dimensional bracket, a light source, an acousto-optic modulator, an amplifier, a beam splitter, and a detection assembly, wherein the number of detection assemblies is three;

[0009] The light source, acousto-optic modulator, amplifier, and beam splitter are connected in sequence, the beam splitter is provided with three output ends, and each output end corresponds to a detection assembly one by one;

[0010] The detection assembly includes: a single-mode optical fiber, a 3DB coupler, a detection optical fiber, a polarization scrambler, a beam combiner, and a photodiode;

[0011] The 3DB coupler is connected to a beam splitter through a single-mode optical fiber. The output ends of the 3DB coupler are respectively connected to a polarization scrambler and a beam combiner, and a detection optical fiber is arranged on the 3DB coupler; the output end of the polarization scrambler is connected to the beam combiner, and the output end of the beam combiner is connected to the photodiode;

[0012] The detection optical fiber includes a fiber core, a fiber cladding, a weak grating, and a magnetostrictive material layer; a fiber cladding is arranged outside the fiber core, a magnetostrictive material layer is regularly arranged on the fiber cladding, and a weak grating is uniformly arranged in the fiber core. The positions of the weak grating and the magnetostrictive material layer correspond one by one;

[0013] The detection optical fiber is arranged on a three-dimensional bracket; the three-dimensional bracket includes an optical fiber winding disc and a base. The number of the optical fiber winding discs is three, and the optical fiber winding discs are regularly arranged on the base. The three detection optical fibers are respectively wound around the three optical fiber winding discs in a one-to-one correspondence.

[0014] The round cap shell is a non-magnetic material round cap shell.

[0015] The magnetostrictive material layer includes a positive magnetostrictive material layer and a negative magnetostrictive material layer; the positive magnetostrictive material layer and the negative magnetostrictive material layer are alternately arranged outside the fiber cladding.

[0016] The three optical fiber winding discs are respectively arranged corresponding to the XYZ axes.

[0017] The optical fiber winding disc is arranged on the base through a fixing screw, and the position of the optical fiber winding disc can be adjusted.

[0018] Through the above design scheme, the present invention provides a device that can quickly and accurately detect weak magnetic field changes, significantly improving the sensitivity of magnetic field anomaly detection. It can still work reliably in a complex environment. The structure of alternately arranging the positive magnetostrictive material layer and the negative magnetostrictive material layer outside the fiber cladding can effectively suppress the mode hopping phenomenon, improve the signal-to-noise ratio of light, and is easy to achieve consistency. There is no electromagnetic radiation as a whole; this application is simple and easy to implement, has strong reliability, and accurate positioning. It can realize real-time and accurate monitoring of weak magnetic fields, and adopts a method of staggering the arrangement order of its magnetostrictive materials and placing them parallel to each other, greatly increasing the stability of the sensor and achieving three-dimensional omnidirectional dead-angle-free monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the optical path system of the present invention;

[0020] Figure 2Structural schematic diagram of the detection optical fiber of the present invention;

[0021] Figure 3 Structural schematic diagram of the three-dimensional bracket of the present invention;

[0022] 1 - optical fiber core, 2 - optical fiber cladding, 3 - weak grating, 4 - magnetostrictive material layer, 5 - light source, 6 - acousto-optic modulator, 7 - amplifier, 8 - beam splitter, 9 - single-mode optical fiber, 10 - 3DB coupler, 11 - detection optical fiber, 12 - polarization scrambler, 13 - combiner, 14 - photodiode, 16 - optical fiber winding disk, 18 - base. Specific embodiments

[0023] The present application will be further described in conjunction with the accompanying drawings:

[0024] A spatial electric field detection optical fiber sensor, characterized in that it includes: a round cap shell, a three-dimensional bracket, a light source 5, an acousto-optic modulator 6, an amplifier 7, a beam splitter 8 and a detection assembly;

[0025] The round cap shell is provided with a three-dimensional bracket, a light source 5, an acousto-optic modulator 6, an amplifier 7, a beam splitter 8 and a detection assembly, wherein the number of detection assemblies is three;

[0026] The light source 5, the acousto-optic modulator 6, the amplifier 7 and the beam splitter 8 are connected in sequence, the beam splitter 8 is provided with three output ends, and each output end corresponds to a detection assembly one by one;

[0027] The detection assembly includes: a single-mode optical fiber 9, a 3DB coupler 10, a detection optical fiber 11, a polarization scrambler 12, a combiner 13, and a photodiode 14;

[0028] The 3DB coupler 10 is connected to the beam splitter 8 through a single-mode optical fiber 9, the output ends of the 3DB coupler 10 are respectively connected to the polarization scrambler 12 and the combiner 13, and a detection optical fiber 11 is provided on the 3DB coupler 10; the output end of the polarization scrambler 12 is connected to the combiner 13, and the output end of the combiner 13 is connected to the photodiode 14;

[0029] The detection optical fiber 11 includes an optical fiber core 1, an optical fiber cladding 2, a weak grating 3 and a magnetostrictive material layer 4; an optical fiber cladding 2 is provided outside the optical fiber core 1, a magnetostrictive material layer 4 is regularly provided on the optical fiber cladding 2, and a weak grating 3 is uniformly provided in the optical fiber core 1, and the positions of the weak grating 3 and the magnetostrictive material layer 4 correspond one by one;

[0030] The detection optical fiber 11 is arranged on a three-dimensional support; the three-dimensional support includes an optical fiber winding disc 16 and a base 18. The number of the optical fiber winding discs 16 is three, and the optical fiber winding discs 16 are regularly arranged on the base 18. The three detection optical fibers 11 are respectively wound around the three optical fiber winding discs 16 in a one-to-one correspondence.

[0031] The round cap shell is a non-magnetic material round cap shell.

[0032] The magnetostrictive material layer 4 includes a positive magnetostrictive material layer and a negative magnetostrictive material layer; the positive magnetostrictive material layer and the negative magnetostrictive material layer are alternately arranged on the outer layer of the optical fiber cladding 2.

[0033] The three optical fiber winding discs 16 are respectively arranged corresponding to the X, Y, and Z axes.

[0034] The number of the detection assemblies is three, which are respectively responsible for detecting in the corresponding directions of the X, Y, and Z axes.

[0035] The optical fiber winding disc 16 is arranged on the base 18 through a fixing screw, and the position of the optical fiber winding disc 16 can be adjusted.

[0036] The magnetostrictive material layer 4 is an iron-based composite material magnetostrictive material layer;

[0037] The position of the optical fiber winding disc 16 on the base 18 can be adjusted, which is convenient for the operator to adjust according to the environment of the detection site.

[0038] The three optical fiber winding discs 16 are respectively arranged corresponding to the X, Y, and Z axes, so that the three detection optical fibers 11 can respectively detect the three directions corresponding to the X, Y, and Z axes, achieving the purpose of detecting the spatial electric field.

[0039] The magnetostrictive effect of the magnetostrictive material layer 4 causes the optical fiber to deform through the electromagnetic field generated by the electric field, and then changes the optical signal to realize electric field detection. Compared with the traditional electric field detection technology, its advantages include: high sensitivity, capable of detecting weak electromagnetic field changes. Strong anti-interference ability, and optical fiber sensing is not affected by electromagnetic interference. It can be monitored in real time and has the advantage of fast response speed.

[0040] The cladding of the detection optical fiber 11 adopts a magnetostrictive material layer 4 with a specific composition (such as an iron-based composite material), and its deformation characteristics are highly sensitive to the low-frequency strong magnetic field generated by lightning (typical frequency range 1Hz - 1MHz), while the response to high-frequency environmental electromagnetic noise (such as mobile phone signals, Wi-Fi, etc.) is extremely weak, thus realizing natural frequency filtering. The electromagnetic field has the characteristics of being transient and high-intensity, while the daily environmental magnetic fields (such as the geomagnetic field, electrical magnetic fields) are mostly steady-state or low-frequency weak fields. The magnetostrictive material filters out most of the background interference unrelated to lightning through threshold design, such as only responding to magnetic fields exceeding a specific intensity. Thus, the disadvantage that the existing electric field sensors are vulnerable to interference is solved.

[0041] Under the action of a magnetic field, the magnetic moments inside the magnetostrictive material tend to align with the external magnetic field, that is, the size of the magnetostrictive material layer 4 increases in the magnetic field direction, resulting in elongation or compression. The magnetostrictive material is sprayed on the outside of the optical fiber cladding 2. Under the action of the expansion and compression of the magnetostrictive material, the period, refractive index, and intensity of the weak grating 3 will change, and the refractive index, shape, and mode field distribution of the optical fiber core 1 will change.

[0042] The light source 5 emits a broadband optical signal, which is frequency-modulated and pulse-controlled by the acousto-optic modulator 6. The amplifier 7 enhances the power of the modulated optical signal to ensure the signal-to-noise ratio in long-distance transmission. Here, optical heterodyne detection technology is adopted. The beam splitter 8 transmits the optical signal to the spatial electric field detection optical fibers 11 in the X-axis, Y-axis, and Z-axis directions. Among them, the single-mode optical fiber monitoring the Y-axis transmits the optical signal to the 3dB coupler 10, which divides the light into two paths: the reference optical path and the sensing optical path. The sensing optical path enters the magnetostrictive loop cladding fiber sensor 11. This sensor utilizes the characteristics of the magnetostrictive material. When the strong magnetic field generated by lightning acts on the sensor, the magnetic field will cause a change in the refractive index of the optical fiber cladding or a shift in the grating period, thereby changing the phase and wavelength of the transmitted optical signal. The polarization controller 12 dynamically adjusts the polarization state of the reference optical path to match the polarization characteristics of the sensing optical path and reduce interference noise. The two optical signals are recombined at the beam combiner 13 to produce an interference effect. The photodiode 14 converts the interfered optical signal into an electrical signal. The system calculates the magnetic field strength, action time, and position information of the electric field by analyzing the wavelength drift or phase difference change of the electrical signal and combining the spatial coordinates of the sensor nodes in the X-axis, Y-axis, and Z-axis directions.

[0043] The main feature of this application is the magnetic field changes in three axial directions: the X direction, the Y direction, and the Z direction. Through the adjustment in the X direction, Y direction, and Z direction, the device can respond flexibly in multiple directions. The effect of magnetic field detection can be optimized by adjusting the angle and position of the optical fiber disk. Due to the adjustability in each direction, the device can adapt to different installation environments, ensuring that the optical fiber can monitor lightning in all directions at the best angle whether it is horizontally, vertically, or inclined. To avoid the influence of the protective housing generating magnetic field interference on the internal optical fiber under the action of the magnetic field, the protective round shell is made of non-magnetic material. This system can cope with complex magnetic field environments, still maintain accurate real-time positioning accuracy in a weak magnetic field environment, monitor minute magnetic field changes in all directions, and resist external interference.

Claims

1. A spatial electric field detection optical fiber sensor, characterized in that: include: A round housing, a three-dimensional bracket, a light source (5), an acousto-optic modulator (6), an amplifier (7), a beam splitter (8) and a detection assembly; The circular shell is provided with a three-dimensional support, a light source (5), an acousto-optic modulator (6), an amplifier (7), a beam splitter (8) and a detection assembly, wherein the number of the detection assemblies is three; The light source (5), the acousto-optic modulator (6), the amplifier (7) and the beam splitter (8) are connected in sequence, and the beam splitter (8) is provided with three output ends, each of which corresponds to a detection assembly one by one; The detection assembly comprises: a single-mode optical fiber (9), a 3DB coupler (10), a detection optical fiber (11), a deflection meter (12), a beam combiner (13) and a photodiode (14); The 3DB coupler (10) is connected to the beam splitter (8) via a single-mode optical fiber (9); the output end of the 3DB coupler (10) is respectively connected to a deflection meter (12) and a beam combiner (13); and a detection optical fiber (11) is provided on the 3DB coupler (10); the output end of the deflection meter (12) is connected to the beam combiner (13), and the output end of the beam combiner (13) is connected to a photodiode (14); The detection optical fiber (11) comprises an optical fiber core (1), an optical fiber cladding (2), a weak grating (3) and a magnetostrictive material layer (4); the optical fiber core (1) is provided with an optical fiber cladding (2), the magnetostrictive material layer (4) is regularly provided on the optical fiber cladding (2), and the optical fiber core (1) is evenly provided with a weak grating (3), and the positions of the weak grating (3) and the magnetostrictive material layer (4) correspond one to one; The detection optical fiber (11) is arranged on a three-dimensional bracket; the three-dimensional bracket comprises an optical fiber winding disk (16) and a base (18), the number of the optical fiber winding disks (16) is three, the optical fiber winding disks (16) are regularly arranged on the base (18), and the three detection optical fibers (11) are arranged on the three optical fiber winding disks (16) in a one-to-one correspondence.

2. The optical fiber sensor for detecting a spatial electric field according to claim 1, characterized in that: The round cap shell is a round cap shell made of non-magnetic material.

3. The optical fiber sensor for detecting a spatial electric field according to claim 1, characterized in that: The magnetostrictive material layer (4) comprises a positive magnetostrictive material layer and a negative magnetostrictive material layer; the positive magnetostrictive material layer and the negative magnetostrictive material layer are alternately arranged on the outer layer of the optical fiber cladding (2).

4. The optical fiber sensor for detecting a spatial electric field according to claim 1, characterized in that: The three optical fiber winding discs (16) are arranged corresponding to the XYZ axes respectively.

5. The optical fiber sensor for detecting a spatial electric field according to claim 1, characterized in that: The optical fiber winding disk (16) is arranged on the base (18) by means of fixing screws, and the position of the optical fiber winding disk (16) can be adjusted.

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