Reflective high sensitivity electric field sensor

Abstract

The application relates to the technical field of optical electric field sensors, in particular to a reflection type high-sensitivity electric field sensor which comprises a packaging shell, an input polarization maintaining optical fiber collimator, a polarizer, a 1 / 4 wave plate, a first lithium niobate crystal, a mirror and an output single-mode optical fiber collimator; the input polarization maintaining optical fiber collimator is arranged in an input end packaging cavity, and one end of the input polarization maintaining optical fiber collimator is provided with the polarizer, the 1 / 4 wave plate, the first lithium niobate crystal and the mirror; a second lithium niobate crystal, a detection polarizer and the output single-mode optical fiber collimator are further arranged in the input end packaging cavity, and the output single-mode optical fiber collimator is arranged in an output end packaging cavity; the main shafts of the first lithium niobate crystal and the second lithium niobate crystal are arranged in a mutually orthogonal mode; the transmission vibration directions of the polarizer and the detection polarizer are arranged in a mutually perpendicular mode; the lithium niobate crystal is used in the x-axis light transmission and z-direction electric field, and the maximum electro-optic coefficient gamma33 of the lithium niobate crystal is used to improve the sensitivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical electric field sensors, in particular to a reflective high-sensitivity electric field sensor. BACKGROUND

[0002] With the rapid development and implementation of new power systems, advanced electric field measurement and sensing technology is of great significance to the intelligentization and safe and stable operation of the implemented power grid. With the increase of voltage level and capacity of the power system, the measurement and protection requirements are continuously improved, and the shortcomings of the traditional electric field sensor are increasingly prominent, mainly as follows: 1. Poor anti-electromagnetic interference ability, the traditional electric field sensor contains a large number of electronic components, which is easily affected by electromagnetic interference in a complex electromagnetic environment; 2. Difficulty in insulation, especially above 500kV, the volume, weight and price of the transformer are not proportional to the insulation; 3. The magnetic saturation, narrow frequency band and slow response speed inherent in the structure of the transformer core, compared with the optical electric field sensor, which has the advantages of wide frequency band, large dynamic range, fast response speed, no external power supply, and adaptation to large field strength measurement. The optical electric field sensor can directly measure the time-domain waveform of the external electric field, providing a better solution for voltage monitoring.

[0003] At present, the measurement of external electric field through the electro-optic effect of optical waveguide or electro-optic crystal has become one of the important ways to measure external electric field. The optical waveguide electric field sensor has the advantages of small size and high sensitivity, but its manufacturing process is complex. Compared with it, the bulk electro-optic crystal type electric field sensor is easy to manufacture and is a full dielectric structure, which is suitable for strong electric field measurement.

[0004] At present, the research on lithium niobate bulk crystal type electric field sensor mainly focuses on how to improve the sensitivity of the sensor and realize multi-dimensional electric field measurement. In order to avoid the influence of natural birefringence of the crystal, improve the temperature stability of the sensor, the sensor usually adopts the mode of z-axis light transmission. However, due to the use of z-axis light transmission mode of the crystal, only the lowest electro-optic coefficient γ22 of lithium niobate crystal can be utilized, thereby reducing the sensitivity of the sensor. Based on this, a reflective high-sensitivity electric field sensor is developed, which uses a piece of x-axis light transmission, z-direction electric field added lithium niobate crystal, utilizes its maximum electro-optic coefficient γ33, and effectively improves the sensitivity of the sensor SUMMARY

[0005] The present application is directed to the deficiencies of the prior art, and proposes a reflective high-sensitivity electric field sensor, which uses x-axis light transmission, z-direction electric field added lithium niobate crystal, utilizes its maximum electro-optic coefficient γ33 to improve the sensitivity, and cascades the same crystal orthogonal to the z-axis to eliminate the influence of natural birefringence and enhance the temperature stability.

[0006] The technical implementation scheme of the present application is:

[0007] The reflective high-sensitivity electric field sensor comprises a packaging shell, an input polarization-maintaining fiber collimator, a polarizer, a quarter-wave plate, a first lithium niobate crystal, a reflector and an output single-mode fiber collimator. The input polarization-maintaining fiber collimator is arranged in an input end packaging cavity, and one end of the input polarization-maintaining fiber collimator is provided with a polarizer, a quarter-wave plate, a first lithium niobate crystal and a reflector; a second lithium niobate crystal, a polarizer and an output single-mode fiber collimator are also provided inside the input end packaging cavity, and the output single-mode fiber collimator is provided at the output end. Inside the output end packaging cavity; the main axes of the first lithium niobate crystal and the second lithium niobate crystal are arranged orthogonally to each other; the transmission directions of the polarizer and the analyzer are arranged perpendicular to each other; the output end face of the input polarization-maintaining fiber collimator is parallel to the light-transmitting surface of the polarizer, 1 / 4 wave plate, the first lithium niobate crystal, the reflector, the second lithium niobate crystal, and the analyzer, and the input end face of the output single-mode fiber collimator is also parallel to them, thereby ensuring the high efficiency of light transmission; the input end packaging cavity and the output end packaging cavity are both fixed in the packaging shell.

[0008] Optionally, the transmission direction of the polarizer forms an angle of 45° with the z-axis of the first lithium niobate crystal.

[0009] Optionally, it also includes a tunable polarization-maintaining light source, a photodetector and an oscilloscope, wherein the tunable polarization-maintaining light source is connected to the sensor via a polarization-maintaining optical fiber; the sensor is connected to the photodetector via a single-mode optical fiber; and the photodetector is connected to the oscilloscope via an oscilloscope probe line.

[0010] Optionally, the polarization-maintaining optical fiber is a panda-type polarization-maintaining optical fiber, and the beat length of the polarization-maintaining optical fiber is 2 mm-4 mm.

[0011] Optionally, the input end packaging cavity is a rectangular structure, and a plurality of grooves are opened inside the input end packaging cavity, in which the input polarization-maintaining fiber collimator, polarizer, 1 / 4 wave plate, first lithium niobate crystal, reflector, second lithium niobate crystal and analyzer are respectively installed.

[0012] Optionally, the input polarization-maintaining fiber collimator is a cylindrical glass collimator, and the output end face of the input polarization-maintaining fiber collimator is a plane; the length of the input polarization-maintaining fiber collimator is 8 mm-12 mm, and the diameter is 2 mm-3 mm.

[0013] Optionally, the polarizer and the analyzer are both in a cubic structure, and the length, width and height of the polarizer and the analyzer are all 3mm-5mm; the 1 / 4 wave plate is a circular sheet, and the radius of the upper and lower bases of the 1 / 4 wave plate is 2mm-3mm, and the thickness is 1-1.5mm; the first lithium niobate crystal and the second lithium niobate crystal are both optical-grade crystals in a cuboid shape, and the length, width and height of the first lithium niobate crystal and the second lithium niobate crystal are all 30mm-42mm, 4mm-6mm and 4mm-6mm.

[0014] Optionally, the two reflective structures of the reflector are both in a triangular prism shape, and the bottom surface of the reflector is an isosceles right triangle, the length of the reflector is 4mm-6mm, and the height of the reflector is 4mm-6mm.

[0015] Optionally, the input end packaging cavity and the output end packaging cavity are both made of zirconium oxide material, and the input end packaging cavity is internally provided with a groove matched with the output single-mode optical fiber collimator, and the external dimensions of the output end packaging cavity are 14mm-20mm in length, 16mm-20mm in width and 10mm-14mm in height.

[0016] Optionally, the packaging shell is in a rectangular cavity structure, and the external dimensions of the packaging shell are 74mm-84mm in length, 18mm-22mm in width and 14mm-16mm in height.

[0017] The working principle of the technical solution is as follows:

[0018] The present application has the following advantages:

[0019] The present application discloses a high-sensitivity lithium niobate birefringent crystal electric field sensor. In order to improve the sensitivity, the x-axis light transmission and z-direction electric field lithium niobate crystal is selected, which fully utilizes the maximum electro-optic coefficient γ33, so that the sensor is more sensitive to the change of electric field. In order to optimize the stability, another x-axis light transmission lithium niobate crystal with orthogonal z-axis to the first crystal is cascaded, which accurately eliminates the interference caused by natural birefringence and ensures the stable performance of the sensor in different temperature environments. At the same time, the reflective structure is innovatively adopted, which greatly compresses the volume of the sensor, opens up a new path for the research and development of high-sensitivity lithium niobate crystal electric field sensor, and provides a highly breakthrough design scheme. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The present application is a structural schematic diagram.

[0021] The meanings of the reference numerals in the figure are: 1- packaging shell, 2- input end packaging cavity, 3- input polarization-maintaining fiber collimator, 4- polarizer, 5- 1 / 4 wave plate, 6- first lithium niobate crystal, 7- reflecting mirror, 8- second lithium niobate crystal, 9- polarizer, 10- output single-mode fiber collimator, 11- output end packaging cavity, 12- single-mode optical fiber, 13- photodetector, 14- oscilloscope probe line, 15- oscilloscope, 16- tunable polarization-maintaining light source, 17- polarization-maintaining optical fiber, 18- sensor. DETAILED DESCRIPTION

[0022] To make the objectives, technical solutions, and advantages of the present invention more apparent, the present invention will be further described in detail below with reference to the accompanying drawings. It is hereby stated that any directional terms such as "up," "down," "left," "right," "front," "back," "inside," and "outside" that appear or will appear herein are based solely on the accompanying drawings and are not intended to limit the present invention.

[0023] like Figure 1 As shown, a reflective high-sensitivity electric field sensor includes a packaging shell 1, an input polarization-maintaining fiber collimator 3, a polarizer 4, a quarter-wave plate 5, a first lithium niobate crystal 6, a reflector 7, and an output single-mode fiber collimator 10. The input polarization-maintaining fiber collimator 3 is arranged in an input end packaging cavity 2, and one end of the input polarization-maintaining fiber collimator 3 is provided with a polarizer 4, a quarter-wave plate 5, a first lithium niobate crystal 6, and a reflector 7; a second lithium niobate crystal 8, an analyzer 9, and an output single-mode fiber collimator 10 are further provided inside the input end packaging cavity 2, and the output single-mode fiber collimator 10 It is arranged inside the output end packaging cavity 11; the main axes of the first lithium niobate crystal 6 and the second lithium niobate crystal 8 are arranged orthogonally to each other; the transmission directions of the polarizer 4 and the analyzer 9 are arranged perpendicular to each other; the output end face of the input polarization-maintaining fiber collimator 3 is parallel to the light-transmitting surface of the polarizer 4, 1 / 4 wave plate 5, the first lithium niobate crystal 6, the reflector 7, the second lithium niobate crystal 8, and the analyzer 9, and the input end face of the output single-mode fiber collimator 10 is also parallel to them, thereby ensuring the high efficiency of light transmission; the input end packaging cavity 2 and the output end packaging cavity 11 are both fixed in the packaging shell 1.

[0024] It should be noted that the principal axes of the first lithium niobate crystal 6 and the second lithium niobate crystal 8 are arranged orthogonally to each other, meaning that their principal axes are perpendicular to each other. This has a significant impact on light propagation. When light propagates between the two crystals, the refractive index and polarization state will change according to the principle of birefringence. In optoelectronic applications, such as electro-optic modulation and nonlinear optical frequency conversion, this orthogonal combination can utilize the different principal axis characteristics to finely control the phase and polarization of light, improve frequency conversion efficiency, and thus increase the sensitivity of the sensor.

[0025] It needs to be further explained that, on the one hand, a special lithium niobate crystal is cascaded, the x-axis of which transmits light and the z-axis of which is orthogonal to the z-axis of the first crystal, thereby ingeniously eliminating the influence of natural birefringence and practically improving the temperature stability of the device; on the other hand, a reflective structure is boldly adopted, which has broken through and greatly reduced the volume of the electric field sensor, injecting new vitality into the development of related technologies. The advantage of this method is that the other lithium niobate crystal mentioned here has the characteristic of "x-axis light transmission", which means that light can smoothly propagate along the x-axis direction of the crystal; at the same time, its "z-axis is orthogonal to the z-axis of the first crystal", that is, the z-axis directions of the two crystals are perpendicular to each other. When such two crystals are reasonably cascaded, the original influence of natural birefringence can be offset or compensated through ingenious optical principles and mutual interaction within the crystal, thereby reducing the adverse effects caused by natural birefringence.

[0026] As shown in Figure 1 The polarization direction of the polarizer 4 is at an angle of 45° with the z-axis of the first lithium niobate crystal 6; further comprising a tunable polarization-maintaining light source 16, a photodetector 13 and an oscilloscope 15, the tunable polarization-maintaining light source 16 is connected with the sensor 18 through a polarization-maintaining optical fiber 17; the sensor 18 is connected with the photodetector 13 through a single-mode optical fiber 12; the photodetector 13 is connected with the oscilloscope 15 through an oscilloscope probe line 14; the polarization-maintaining optical fiber 17 is a panda-type polarization-maintaining optical fiber, the beat length of the polarization-maintaining optical fiber 17 is 3mm; the input end packaging cavity 2 is a cuboid structure, and a plurality of grooves are formed in the input end packaging cavity 2, and the grooves are respectively installed with an input polarization-maintaining optical fiber collimator 3, a polarizer 4, a 1 / 4 wave plate 5, a first lithium niobate crystal 6, a mirror 7, a second lithium niobate crystal 8 and a polarimeter 9.

[0027] It needs to be explained that when the polarization direction of the polarizer 4 is at an angle of 45° with the z-axis of the first lithium niobate crystal 6, the electric field vector of the linearly polarized light will be decomposed into two components parallel and perpendicular to the z-axis after entering the first lithium niobate crystal 6, and the first lithium niobate crystal 6 has an electro-optic effect, when an electric field is applied in the z direction, the two components will produce a phase difference due to the change of the refractive index of the crystal; this 45° angle setting makes the sizes of the two components equal, and in the process of electro-optic modulation, the electro-optic coefficient of the crystal can be more effectively utilized to change the polarization state of light, thereby improving the response sensitivity to the electric field.

[0028] It needs to be further explained that the tunable polarization maintaining light source 16 as the starting end of the optical signal can generate and adjust the light with a specific polarization state, which is accurately transmitted to the sensor 18 through the polarization maintaining optical fiber 17, to provide the sensor with high-quality and adaptive characteristic input light, and to ensure the accurate detection of the sensor based on the electro-optic effect; the photoelectric detector 13 undertakes the key task of converting the optical signal into an electrical signal, receives the light processed by the sensor 18 through the single-mode optical fiber 12, converts it into an electrical signal and can be preliminarily processed, and ensures the feasibility of subsequent detection and analysis; and the oscilloscope 15 focuses on the visual presentation and analysis of the electrical signal, receives the electrical signal output by the photoelectric detector 13, and displays it in an intuitive form such as a waveform, so as to facilitate the monitoring of the system operation state, the troubleshooting, and the auxiliary evaluation of the system performance, and the three work together to achieve the purpose of optical and electrical signal processing and detection.

[0029] As shown in Figure 1 the input end packaging cavity 2 is made of zirconia material, and the overall structure is a cuboid, the inside is precisely grooved according to the size of the optical element, the external dimensions are: length 64mm, width 16mm, height 10mm; the input polarization maintaining optical fiber collimator 3 and the polarization maintaining optical fiber 17 are connected and solidified by glue injection, which is a cylindrical glass material, the output end face is a plane, the external dimensions are: length 10mm, diameter 2.8mm; the polarizer 4 and the analyzer 9 are both square structures, which are glass materials, the surface is coated with silver reflective film, the external dimensions are: length 5mm, width 5mm, height 5mm; the 1 / 4 wave plate 5 is a cylindrical quartz crystal material, the upper and lower bottom surfaces have a radius of 3mm, and the height is 1mm; the first lithium niobate crystal 6 and the second lithium niobate crystal 8 are both optical-grade crystals, which are cuboid structures, the external dimensions are: length 40mm, width 4mm, height 4mm; the two reflective structures of the reflector 7 are both triangular prisms, the bottom surfaces of the two reflective structures are isosceles right triangles, the external dimensions are: length of the right angle side 6mm, height 6mm; the output single-mode optical fiber collimator 10 and the polarization maintaining optical fiber 12 are connected and solidified by glue injection, which is a cylindrical glass material, the output end face is a plane, the external dimensions are: length 10mm, diameter 2.8mm; the output end packaging cavity 11 is made of acrylic material, the overall structure is a cuboid, the inside is precisely grooved according to the size of the output single-mode optical fiber collimator, the external dimensions are: length 14mm, width 16mm, height 10mm; the output single-mode optical fiber collimator 10 and the input polarization maintaining optical fiber collimator 3 are a pair of collimators, and the coupling distance of the two collimators is 65mm; the packaging shell 1 is made of zirconia material, and the packaging shell is a cuboid structure, the external dimensions are: length 74mm, width 18mm, height 16mm.

[0030] The mounting method of the mechanism is as follows:

[0031] Place the first lithium niobate crystal 6 and the second lithium niobate crystal 8 in the input end packaging cavity 2 and fix them with glue. Align the slow axis of the input polarization-maintaining fiber collimator 3 with the x-axis of the first lithium niobate crystal 6, adjust its output end face to be parallel to the light-transmitting surface of the first lithium niobate crystal 6 and fix them with glue; the light-transmitting axis of the polarizer 4 is parallel to the x-axis of the first lithium niobate crystal 6, adjust its output end face to be parallel to the light-transmitting surface of the first lithium niobate crystal 6 and fix them with glue, and the light-transmitting surface of the 1 / 4 wave plate 5 is parallel to the light-transmitting surface of the first lithium niobate crystal 6 and fix them with glue; adjust the reflecting surfaces of the two reflecting structures of the reflector 7 to form a 45° angle with the light-transmitting surfaces of the first lithium niobate crystal 6 and the second lithium niobate crystal 8 respectively and fix them with glue; adjust the light-transmitting axis of the analyzer 9 to be perpendicular to the x-axis of the second lithium niobate crystal 8, adjust its output end face to be parallel to the light-transmitting surface of the second lithium niobate crystal 8 The output single-mode optical fiber collimator 10 is fixed in the output end packaging cavity by injection glue. After the optical glue of each component inside the input end packaging cavity 2 and the output end packaging cavity 11 is completely cured, it is placed on the optical adjustment frame for optical path coupling. When the optical path coupling loss is minimized, the relative positions of the two packaging cavities are fixed by the packaging shell 1, and the production of the sensor 18 is completed. After the linearly polarized light input by the tunable polarization-maintaining light source 16 is aligned with the slow axis of the polarization-maintaining optical fiber 17, it enters the sensor 18. The optical signal output by the sensor 18 enters the photodetector 13 through the single-mode optical fiber 12 for photoelectric conversion, and is finally transmitted to the oscilloscope 15 through the oscilloscope probe line 14 for display output, completing the measurement of the measured electric field.

[0032] The working principle of the present invention is as follows:

[0033] For crystal 1, the external electric field E is along the z-axis of the crystal. According to the electro-optic effect of lithium niobate crystal, the principal axis refractive index of crystal 1 can be expressed as

[0034]

[0035] In Formula 1, γ33 and γ13 are the electro-optical coefficients of the lithium niobate crystal, no is the refractive index of o-light, ne is the refractive index of e-light, and κ is the ratio of the external to internal electric fields of the lithium niobate crystal. When a light wave is input along the x-axis of crystal 1, it is decomposed into o-light vibrating along the crystal's z-axis and e-light vibrating along the crystal's y-axis. Formula 1 shows that the phase difference between the two polarization directions of the light wave passing through crystal 1 is:

[0036]

[0037] In formula 2, L1 is the length of crystal 1, and λ is the wavelength of light in vacuum.

[0038] For crystal 2, since the external electric field E is along the y-axis of the crystal, the principal axis refractive index of crystal 2 can be expressed as:

[0039]

[0040] From equation 3, the phase difference of the light wave passing through the crystal 2 in two polarization directions is:

[0041]

[0042] In equation 4, L2 is the length of the crystal 2. When L1 = L2 = L, from equation 2 and equation 4, the phase difference of the light wave passing through the crystal 1 and the crystal 2 in two polarization directions along the x-axis is:

[0043]

[0044] It is noted that for the existing z-propagation, the applied electric field E is along the x or y axis of the crystal, the phase difference of the light wave passing through the crystal in two polarization directions is:

[0045]

[0046] From equation 5 and equation 6, it is known that because the designed double crystal structure utilizes the maximum electro-optic coefficient γ33 of the lithium niobate crystal, the phase change of the light wave passing through the double crystal is significantly increased when the lengths of the crystals are the same, thereby improving the sensitivity of the device. In addition, from equation 5, it can be seen that the phase difference caused by the natural birefringence is offset after the light wave passes through the double crystal, and it is noted that the natural light birefringence is greatly affected by temperature, so the designed sensor will have better stability in theory.

[0047] From equation 5, when Dφ = π, the half-wave electric field of the sensor is:

[0048]

[0049] Using πE(t) / Eπ to represent the phase change of the light wave, the output light power Pout of the light wave output by the crystal after being detected by the polarizer can be represented as:

[0050]

[0051] In equation 8, a is the light path loss coefficient, Pin is the input light power, and φ0 is the static phase difference of the light wave when no electric field is applied.

[0052] When φ0 = 90° and πE(t) / Eπ << 1, equation 8 can be simplified as:

[0053]

[0054] According to equation 9, the output light of the sensor output by the photoelectric conversion is:

[0055]

[0056] G(V / W) in formula 10 is the photoelectric conversion coefficient of the photodetector. As can be seen from formula 10, the output electric signal of the sensing system is proportional to the measured electric field E(t).

[0057] It should be noted that the present application proposes a high-sensitivity lithium niobate birefringent crystal electric field sensor design scheme. On the one hand, a lithium niobate crystal with x-axis light transmission and z-direction electric field application is selected as the core component, which fully utilizes the maximum electro-optic coefficient γ33 of the crystal, so that the sensing sensitivity of the sensor to the electric field is greatly improved, and the extremely weak electric field change signal can be accurately captured, greatly widening the application scenarios and detection accuracy range.

[0058] It should be further pointed out that another piece of lithium niobate crystal with x-axis light transmission but z-axis orthogonal layout to the first piece of crystal is ingeniously cascaded. In this way, the adverse interference caused by natural birefringence is successfully eliminated, and the temperature adaptability of the device is fundamentally strengthened, ensuring that the sensor can still maintain stable and reliable performance under complex and variable temperature conditions, laying a solid foundation for long-time and high-precision electric field monitoring operation. What is particularly prominent is that the present application breaks through the design of the reflective structure, which makes the volume of the entire electric field sensor be compressed to the extreme. Not only does it effectively save the installation space and reduce the equipment integration difficulty, but also it creates the possibility for precise perception of electric field in some special fields with strict space requirements, such as miniature electronic devices, precision instrument cabins, etc., and truly opens up a new way for the research and application of high-sensitivity lithium niobate crystal electric field sensor.

[0059] The embodiments of the present application are described in detail above in combination with the drawings, but the present application is not limited to the above-mentioned embodiments. Within the knowledge range possessed by those skilled in the art, various changes can be made without departing from the purpose of the present application.

Claims

1. A reflective high sensitivity electric field sensor comprising a package housing (1), an input polarization maintaining fiber collimator (3), a polarizer (4), a 1 / 4 wave plate (5), a first lithium niobate crystal (6), a mirror (7) and an output single mode fiber collimator (10), characterized in that, The input polarization maintaining fiber collimator (3) is arranged in the input packaging cavity (2), and one end of the input polarization maintaining fiber collimator (3) is provided with a polarizer (4), a 1 / 4 wave plate (5), a first lithium niobate crystal (6) and a mirror (7); The input packaging cavity (2) is further provided with a second lithium niobate crystal (8), a polarizing analyzer (9) and an output single-mode fiber collimator (10) inside, and the output single-mode fiber collimator (10) is arranged inside the output packaging cavity (11); The main axes of the first lithium niobate crystal (6) and the second lithium niobate crystal (8) are arranged orthogonally to each other; The vibration transmission directions of the polarizer (4) and the polarizing analyzer (9) are arranged perpendicularly to each other; The output end face of the input polarization maintaining fiber collimator (3) is parallel to the light transmission faces of the polarizer (4), the 1 / 4 wave plate (5), the first lithium niobate crystal (6), the mirror (7), the second lithium niobate crystal (8) and the polarizing analyzer (9), and the input end face of the output single-mode fiber collimator (10) is also parallel thereto, so as to ensure the high efficiency of light transmission; The input packaging cavity (2) and the output packaging cavity (11) are both fixed in the packaging shell (1).

2. The reflective high-sensitivity electric field sensor according to claim 1, characterized in that The vibration transmission direction of the polarizer (4) forms a 45° angle with the z-axis of the first lithium niobate crystal (6).

3. The reflective high-sensitivity electric field sensor according to claim 2, characterized in that Further comprising a tunable polarization maintaining light source (16), a photodetector (13) and an oscilloscope (15), the tunable polarization maintaining light source (16) is connected with the sensor (18) through a polarization maintaining fiber (17); The sensor (18) is connected with the photodetector (13) through a single-mode fiber (12); The photodetector (13) is connected with the oscilloscope (15) through an oscilloscope probe line (14).

4. The reflective high-sensitivity electric field sensor according to claim 3, characterized in that The polarization maintaining fiber (17) is a panda polarization maintaining fiber, and the beat length of the polarization maintaining fiber (17) is 2mm-4mm.

5. The reflective high-sensitivity electric field sensor according to claim 4, characterized in that The input packaging cavity (2) is a cuboid structure, and a plurality of grooves are formed in the input packaging cavity (2), and the input polarization maintaining fiber collimator (3), the polarizer (4), the 1 / 4 wave plate (5), the first lithium niobate crystal (6), the mirror (7), the second lithium niobate crystal (8) and the polarizing analyzer (9) are respectively arranged in the grooves.

6. The reflective high-sensitivity electric field sensor according to claim 5, characterized in that The input polarization maintaining fiber collimator (3) is a cylindrical glass collimator, and the output end face of the input polarization maintaining fiber collimator (3) is a plane; The length of the input polarization maintaining fiber collimator (3) is 8mm-12mm, and the diameter is 2mm-3mm.

7. The reflective high-sensitivity electric field sensor according to claim 6, characterized in that The polarizer (4) and the polarizing analyzer (9) are both in a square structure, and the length, width and height of the polarizer (4) and the polarizing analyzer (9) are all 3mm-5mm. The 1 / 4 wave plate (5) is a circular sheet, and the radius of the upper and lower bottom faces of the 1 / 4 wave plate (5) is 2mm-3mm, and the thickness is 1-1.5mm; The first lithium niobate crystal (6) and the second lithium niobate crystal (8) are both optical-grade crystals in a cuboid structure, and the length, width and height of the first lithium niobate crystal (6) and the second lithium niobate crystal (8) are all 30mm-42mm, 4mm-6mm and 4mm-6mm.

8. The reflective high-sensitivity electric field sensor according to claim 1, characterized in that, The two reflecting structures of the reflector (7) are all triangular prism structures, and the bottom surface of the reflector (7) is an isosceles right triangle, the side length of the reflector (7) is 4mm-6mm, and the height of the reflector (7) is 4mm-6mm.

9. The reflective high-sensitivity electric field sensor according to claim 1, characterized in that, The input end packaging cavity (2) and the output end packaging cavity (11) are both made of zirconium oxide material, the output end packaging cavity (11) is internally provided with a groove matched with the output single-mode optical fiber collimator (10), and the external size of the output end packaging cavity (11) is 14mm-20mm in length, 16mm-20mm in width and 10mm-14mm in height.

10. The reflective high-sensitivity electric field sensor according to claim 1, characterized in that, The packaging shell (1) is a rectangular cavity structure, and the external size of the packaging shell (1) is 74mm-84mm in length, 18mm-22mm in width and 14mm-16mm in height.

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