System and method for measuring three-dimensional magnetic field by using integrated micro-ring device

Abstract

The invention discloses a system and a method for measuring a three-dimensional magnetic field by using an integrated micro-ring device, and belongs to the technical field of optical fiber sensing and magnetic field measurement. The system comprises a light source, a transmission straight waveguide, a polarization controller, a 1: 2 type Y waveguide, two sensing micro-rings (built-in magneto-optical waveguides) perpendicular to each other and a photoelectric detector. According to the invention, by using the asymmetry of the magneto-optical waveguide in the horizontal / vertical direction, transverse magnetization respectively changes TE / TM mode propagation constants; the x / y-axis magnetic field and the z / y-axis magnetic field are sensed through the two micro-rings respectively, and a three-dimensional magnetic field is obtained through simultaneous operation. The device is high in integration level, small in size, simple in process and high in environmental adaptability, and has practical value. According to the invention, each micro-ring measuring device is integrated on a single chip, the integration level is relatively high, the size is small, the process is relatively simple, and the method has relatively high environmental adaptability and practical value.

Description

Technical Field

[0001] This invention relates to the field of integrated optics and magnetic field measurement technology, specifically a system and method for measuring three-dimensional magnetic fields using integrated microring devices. Background Technology

[0002] High-precision, multi-component distributed magnetic field sensing is of great significance in power equipment monitoring, marine exploration, and national defense applications. Optical magnetic field sensing technology, due to its strong anti-interference capabilities and ease of deployment and networking, has gradually become a research hotspot in this field.

[0003] Existing optical magnetic field sensing mechanisms mainly fall into three typical categories: magnetostrictive fiber optic grating sensors, which achieve detection through the conversion relationship between magnetic field, material deformation, and grating wavelength shift; Faraday magneto-optical effect sensors, which invert the magnetic field strength based on the polarization plane rotation angle; and magnetohydrodynamic fiber optic sensors, which rely on the magnetic field to modulate the refractive index of the magnetohydrodynamic fluid to change the light transmission behavior. However, all of these approaches have certain bottlenecks. Faraday and magnetohydrodynamic sensors have special requirements for the optical medium, which limits the system's universality and cost control; magnetostrictive fiber optic gratings, on the other hand, are difficult to balance between sensitivity and dynamic range, and are affected by the interaction of temperature changes and strain, making it difficult to guarantee accuracy under complex operating conditions.

[0004] To address these challenges, integrated optics technology offers a new approach to advancing three-dimensional magnetic field sensing. This approach leverages chip-level optics to achieve simultaneous multi-axial magnetic field sensing, significantly improving sensor integration and multi-dimensional signal acquisition capabilities. Furthermore, it facilitates the construction of an effective temperature-strain-magnetic field decoupling mechanism at the system level, promoting the development of a distributed three-dimensional magnetic sensing system that combines wide measurement range, high precision, and good environmental adaptability. Summary of the Invention

[0005] The purpose of this invention is to provide a system and method for measuring three-dimensional magnetic fields using integrated micro-ring devices. This invention mainly utilizes the fact that when the magneto-optical waveguide structure is asymmetrically distributed in the horizontal and vertical directions, the horizontal transverse magnetization and vertical transverse magnetization will cause changes in the propagation constants of the TE mode and TM mode, respectively. By measuring the effective refractive index of the TE and TM modes, the direction and value of the transverse magnetization intensity can be determined. Then, based on the relevant characteristics of the magneto-optical waveguide, the external magnetic field can be calculated. It has high integration, small size, simple fabrication, and is easy to package.

[0006] The technical solution adopted in this invention is as follows:

[0007] A system for measuring a three-dimensional magnetic field using an integrated microring device includes a light source; a first transmission straight waveguide; a polarization controller; a 1:2 type Y waveguide; a second transmission straight waveguide; a third transmission straight waveguide; a microring on a first sensing chip; a magneto-optical waveguide in the first microring; a first output straight waveguide; a microring on a second sensing chip; a magneto-optical waveguide in the second microring; a second output straight waveguide; a first photodetector; and a second photodetector.

[0008] A light source, a first transmission straight waveguide, a polarization controller, and a 1:2 type Y waveguide are connected in sequence. The first output port of the 1:2 type Y waveguide is connected to the second transmission straight waveguide and coupled into a micro-ring on the first magnetic field sensing chip. After passing through the magneto-optical waveguide in the first micro-ring, it is connected to the first photodetector through the first output straight waveguide as the transmission end for the y-axis and x-axis. The second port of the polarization controller is connected to the third transmission straight waveguide and coupled into a micro-ring on the second magnetic field sensing chip. After passing through the magneto-optical waveguide in the second micro-ring, it is connected to the second photodetector through the second output straight waveguide as the transmission end for the z-axis and y-axis. The micro-rings on the first and second magnetic field sensing chips are placed perpendicular to each other. The first and second photodetectors convert the received optical signals into electrical signals, analyze the changes in the resonance peaks corresponding to the two electrical signals, and obtain the three-dimensional magnetic field strength of the x-axis, y-axis, and z-axis by combining them.

[0009] Furthermore, the light source outputs a light signal with a specific wavelength and power to the first transmission straight waveguide. After the polarization state is adjusted by the polarization controller, the light signal can be split into two paths through the 1:2 type Y waveguide and coupled to the second and third transmission straight waveguides, thus entering the sensing chip. The first path is coupled to the first output straight waveguide after passing through the micro-ring on the first sensing chip and the magneto-optical waveguide in the first micro-ring, and connected to the first photodetector. The second path is coupled to the second output straight waveguide after passing through the micro-ring on the second sensing chip and the magneto-optical waveguide in the second micro-ring, and connected to the second photodetector.

[0010] Furthermore, the first transmission straight waveguide, the 1:2 type Y waveguide, the second transmission straight waveguide, the third transmission straight waveguide, the first output straight waveguide, and the second output straight waveguide are all ridge waveguides.

[0011] Furthermore, the ridge waveguide is integrated on the surface of a lithium niobate single-crystal thin film layer.

[0012] Furthermore, the ridge waveguide has a waveguide width of 0.8 μm and a ridge height of 0.3 μm.

[0013] Furthermore, the ridge waveguide is integrated on the surface of a lithium niobate single crystal thin film layer, which is located on the surface of a silicon dioxide buffer layer, which is located on the surface of a silicon substrate.

[0014] Furthermore, the magneto-optical waveguide in the first microring and the magneto-optical waveguide in the second microring are both composed of an upper cladding, a lower cladding, and a core layer between the upper and lower claddings.

[0015] Furthermore, the core layer is formed by bonding lithium niobate and a first magneto-optical material, the upper cladding layer is composed of a second magneto-optical material, and the lower cladding layer is composed of silicon dioxide.

[0016] Furthermore, the first magneto-optical material is gallium manganese arsenide, with a magneto-optical coefficient of f1≈−10. −9 A / m, the second magneto-optical material 2 is cerium-doped yttrium iron garnet, with a magneto-optical coefficient of f1≈−8.63×10. −8 The saturation magnetization Ms reaches 95.5 kA / m.

[0017] A method for measuring a three-dimensional magnetic field using the system described above includes the following steps:

[0018] S1. Light source outputs optical signal: The light source outputs an optical signal of a specific wavelength and power to the first transmission straight waveguide;

[0019] S2. Optical signal splitting and polarization adjustment: After the optical signal is polarized by the polarization controller, it is split into two paths by the 1:2 type Y waveguide and transmitted to the second and third transmission straight waveguides respectively;

[0020] S3. X-axis and Y-axis magnetic field sensing: The optical signal in the second transmission straight waveguide is coupled into the micro-ring on the first sensing chip. After sensing the magnetic fields of the x-axis and y-axis through the magneto-optical waveguide in the first micro-ring, it is transmitted to the first photodetector through the first output straight waveguide.

[0021] S4. z-axis and y-axis magnetic field sensing: The optical signal in the third transmission straight waveguide is coupled into the micro-ring on the second sensing chip. After sensing the z-axis and y-axis magnetic fields through the magneto-optical waveguide in the second micro-ring, it is transmitted to the second photodetector through the second output straight waveguide.

[0022] S5. Three-dimensional magnetic field calculation: The first and second photodetectors convert the received optical signals into electrical signals. The changes in the resonance peaks corresponding to the two electrical signals are analyzed, and the three-dimensional magnetic field strength along the x, y, and z axes is obtained by combining the results. Beneficial effects of this invention:

[0023] (1) This invention utilizes a novel structure to construct an asymmetric structure of a magneto-optical waveguide in the x and y directions, thereby measuring and analyzing the resonance peaks of the TE and TM modes to obtain the magnetic field strength in both directions, which is a certain degree of simplification compared to the previous triaxial structure.

[0024] (2) The present invention is an integrated optical device with high integration, small size, relatively simple manufacturing process, and easy packaging. Attached Figure Description

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will now be described in further detail with reference to the accompanying drawings, wherein:

[0026] Figure 1 This is a schematic diagram of the structure of a system for measuring three-dimensional magnetic fields using an integrated microring device according to the present invention;

[0027] Figure 2 This is a schematic cross-sectional view of the ridge waveguide in this invention;

[0028] Figure 3 This is a schematic cross-sectional view of the magneto-optical waveguide in this invention.

[0029] In the figure: 1-Light source, 2-First transmission straight waveguide, 3-Polarization controller, 4-Type 1:2 Y waveguide, 5-Second transmission straight waveguide, 6-Third transmission straight waveguide, 7-Micro ring on the first sensor chip, 8-Magneto-optical waveguide in the first micro ring, 9-First output straight waveguide, 10-Micro ring on the second sensor chip, 11-Magneto-optical waveguide in the second micro ring, 12-Second output straight waveguide, 13-First photodetector, 14-Second photodetector, 15-Lithium niobate single crystal thin film layer, 16-Silicon dioxide buffer layer, 17-Silicon substrate, 18-First magneto-optical material, 19-Lithium niobate, 20-Second magneto-optical material, 21-Silicon dioxide. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] See Figure 1 This invention provides a system for measuring a three-dimensional magnetic field using an integrated microring device, comprising: a light source 1; a first transmission straight waveguide 2; a polarization controller 3; a 1:2 type Y waveguide 4; a second transmission straight waveguide 5; a third transmission straight waveguide 6; a microring 7 on a first sensing chip; a magneto-optical waveguide 8 in the first microring; a first output straight waveguide 9; a microring 10 on a second sensing chip; a magneto-optical waveguide 11 in the second microring; a second output straight waveguide 12; a first photodetector 13; and a second photodetector 14.

[0032] Light source 1 outputs a light signal with a specific wavelength and power to the first transmission straight waveguide 2. The first transmission straight waveguide 2 is connected to a 1:2 type Y waveguide 4 through a polarization controller 3. The first output port of the 1:2 type Y waveguide 4 is connected to the second transmission straight waveguide 5, which is coupled into the micro-ring 7 on the first magnetic field sensing chip. After passing through the magneto-optical waveguide 8 in the first micro-ring, it is connected to the first photodetector 13 through the first output straight waveguide 9 as the transmission end of the y-axis and x-axis. The second port of the polarization controller 3 is connected to the third transmission straight waveguide 6, which is coupled into the micro-ring 10 on the second magnetic field sensing chip. After passing through the magneto-optical waveguide 11 in the second micro-ring, it is connected to the second photodetector 14 through the second output straight waveguide 12 as the transmission end of the z-axis and y-axis. The first photodetector (13) and the second photodetector (14) convert the received light signal into an electrical signal, analyze the changes in the resonance peaks corresponding to the two electrical signals, and obtain the three-dimensional magnetic field strength of the x-axis, y-axis, and z-axis by combining them.

[0033] like Figure 2 As shown, the first transmission straight waveguide 2, the 1:2 type Y waveguide 4, the second transmission straight waveguide 5, the third transmission straight waveguide 6, the first output straight waveguide 9, and the second output straight waveguide 12 are all ridge waveguides, integrated on the surface of the lithium niobate single crystal thin film layer 15. The lithium niobate single crystal thin film layer 15 is located on the surface of the silicon dioxide buffer layer 16, and the silicon dioxide buffer layer 16 is located on the surface of the silicon substrate 17.

[0034] like Figure 1 , 3 As shown, the microrings containing magneto-optical waveguides are placed perpendicular to each other along the direction illustrated. The magneto-optical waveguide 8 in the first microring and the magneto-optical waveguide 11 in the second microring both consist of an upper cladding, a lower cladding, and a core layer between the upper and lower claddings. The core layer is mainly formed by bonding lithium niobate 19 and magneto-optical material 18, the upper cladding is composed of magneto-optical material 20, and the lower cladding is composed of silicon dioxide 21. The microring 7 on the first magnetic field sensing chip senses the magnetic fields along the x-axis and y-axis, and the microring 10 on the second magnetic field sensing chip senses the magnetic fields along the z-axis and y-axis.

[0035] In this example, a DFB laser is used as the light source. The first magneto-optical material 18 is selected as gallium manganese arsenide (GaMnAs), with a magneto-optical coefficient of f1≈−10. −9 (A / m). The second magneto-optical material 20 is cerium-doped yttrium iron garnet (Ce:YIG), with a magneto-optical coefficient of f1≈−8.63×10⁻⁶. −8 (A / m), the saturation magnetization Ms reaches 95.5kA / m.

[0036] The first transmission straight waveguide 2, the 1:2 type Y waveguide 4, the second transmission straight waveguide 5, the third transmission straight waveguide 6, the first output straight waveguide 9, and the second output straight waveguide 12 are all ridge waveguides with a waveguide width of 0.8 μm and a ridge height of 0.3 μm.

[0037] This invention also provides a method for measuring a three-dimensional magnetic field using the system described above, comprising the following steps:

[0038] S1. Light source outputs optical signal: The light source outputs an optical signal of a specific wavelength and power to the first transmission straight waveguide;

[0039] S2. Optical signal splitting and polarization adjustment: After the optical signal is polarized by the polarization controller, it is split into two paths by the 1:2 type Y waveguide and transmitted to the second and third transmission straight waveguides respectively;

[0040] S3. X-axis and Y-axis magnetic field sensing: The optical signal in the second transmission straight waveguide is coupled into the micro-ring on the first sensing chip. After sensing the magnetic fields of the x-axis and y-axis through the magneto-optical waveguide in the first micro-ring, it is transmitted to the first photodetector through the first output straight waveguide.

[0041] S4. z-axis and y-axis magnetic field sensing: The optical signal in the third transmission straight waveguide is coupled into the micro-ring on the second sensing chip. After sensing the z-axis and y-axis magnetic fields through the magneto-optical waveguide in the second micro-ring, it is transmitted to the second photodetector through the second output straight waveguide.

[0042] S5. Three-dimensional magnetic field calculation: The first and second photodetectors convert the received optical signals into electrical signals, analyze the changes in the resonance peaks corresponding to the two electrical signals, and obtain the three-dimensional magnetic field strength along the x-axis, y-axis, and z-axis by combining them.

[0043] This invention has the following features and effects:

[0044] 1. Structural innovation simplifies 3D measurement: Through the layout of two mutually perpendicular micro-rings and the asymmetrical design of the magneto-optical waveguide (the core layer is made of lithium niobate bonded to magneto-optical material, and the upper and lower cladding layers are made of magneto-optical material / silicon dioxide), synchronous sensing of the magnetic field of the x / y axis and z / y axis is achieved, simplifying the traditional triaxial measurement structure and improving measurement efficiency and accuracy.

[0045] 2. High integration and practicality: The transmission waveguides in the system are all ridge waveguides integrated on a lithium niobate single crystal thin film layer. The devices have high integration, small size, simple manufacturing process, and are easy to package. At the same time, they have strong anti-interference ability and good environmental adaptability, making them suitable for multiple scenarios such as power equipment monitoring and marine exploration.

[0046] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A system for measuring three-dimensional magnetic fields using an integrated microring device, characterized in that, Includes a light source (1); a first transmission straight waveguide (2); a polarization controller (3); a 1:2 type Y waveguide (4); a second transmission straight waveguide (5); a third transmission straight waveguide (6); a micro-ring on the first sensing chip (7); a magneto-optical waveguide in the first micro-ring (8); a first output straight waveguide (9); a micro-ring on the second sensing chip (10); a magneto-optical waveguide in the second micro-ring (11); a second output straight waveguide (12); a first photodetector (13); and a second photodetector (14). The light source (1), the first transmission straight waveguide (2), the polarization controller (3), and the 1:2 type Y waveguide (4) are connected in sequence. The first output port of the 1:2 type Y waveguide (4) is connected to the second transmission straight waveguide (5), and coupled into the micro-ring (7) on the first magnetic field sensing chip. After passing through the magneto-optical waveguide (8) in the first micro-ring, it is connected to the first photodetector (13) through the first output straight waveguide (9) as the transmission end of the y-axis and x-axis. The second port of the polarization controller (3) is connected to the third transmission straight waveguide (6), and coupled into the second magnetic field. The micro-ring (10) on the sensing chip passes through the magneto-optical waveguide (11) in the second micro-ring and then through the second output straight waveguide (12) to connect to the second photodetector (14) as the transmission end of the z-axis and y-axis; the micro-ring (7) on the first magnetic field sensing chip and the micro-ring (10) on the second magnetic field sensing chip are placed perpendicular to each other; the first photodetector (13) and the second photodetector (14) convert the received optical signal into an electrical signal, analyze the changes in the resonance peaks corresponding to the two electrical signals, and obtain the three-dimensional magnetic field strength of the x-axis, y-axis and z-axis by combining them.

2. The system according to claim 1, characterized in that: The light source (1) outputs a light signal with a specific wavelength and power to the first transmission straight waveguide (2). After the polarization state is adjusted by the polarization controller (3), the light signal can be split into two paths through the 1:2 type Y waveguide (4) and coupled to the second transmission straight waveguide (5) and the third transmission straight waveguide (6) to enter the sensor chip. The first path is coupled to the first output straight waveguide (9) after passing through the micro-ring (7) on the first sensor chip and the magneto-optical waveguide (8) in the first micro-ring, and connected to the first photodetector (13). The second path is coupled to the second output straight waveguide (12) after passing through the micro-ring (10) on the second sensor chip and the magneto-optical waveguide (11) in the second micro-ring, and connected to the second photodetector (14).

3. The system according to claim 1, characterized in that: The first transmission straight waveguide (2), the 1:2 type Y waveguide (4), the second transmission straight waveguide (5), the third transmission straight waveguide (6), the first output straight waveguide (9), and the second output straight waveguide (12) are all ridge waveguides.

4. The system according to claim 3, characterized in that: The ridge waveguide is integrated on the surface of a lithium niobate single crystal thin film layer (15).

5. The system according to claim 3, characterized in that: The ridge waveguide has a waveguide width of 0.8 μm and a ridge height of 0.3 μm.

6. The system according to claim 4, characterized in that: A lithium niobate single crystal thin film layer (15) is located on the surface of a silicon dioxide buffer layer (16), and the silicon dioxide buffer layer (16) is located on the surface of a silicon substrate (17).

7. The system according to claim 1, characterized in that: The magneto-optical waveguide (8) in the first microring and the magneto-optical waveguide (11) in the second microring are both composed of an upper cladding, a lower cladding, and a core layer between the upper and lower cladding.

8. The system according to claim 7, characterized in that: The core layer is formed by bonding lithium niobate (19) and a first magneto-optical material (18), the upper cladding layer is composed of a second magneto-optical material (20), and the lower cladding layer is composed of silicon dioxide (21).

9. The system according to claim 8, characterized in that: The first magneto-optical material is gallium manganese arsenide, with a magneto-optical coefficient of f1≈−10. −9 A / m, the second magneto-optical material 2 is cerium-doped yttrium iron garnet, with a magneto-optical coefficient of f1≈−8.63×10. −8 The saturation magnetization Ms reaches 95.5 kA / m.

10. A method for measuring a three-dimensional magnetic field using the system described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Light source outputs optical signal: The light source (1) outputs an optical signal of a specific wavelength and power to the first transmission straight waveguide (2); S2. Optical signal splitting and polarization adjustment: After the optical signal is polarized by the polarization controller (3), it is split into two paths by the 1:2 type Y waveguide (4) and transmitted to the second transmission straight waveguide (5) and the third transmission straight waveguide (6) respectively. S3. X-axis and Y-axis magnetic field sensing: The optical signal in the second transmission straight waveguide (5) is coupled into the micro-ring (7) on the first sensing chip. After sensing the X-axis and Y-axis magnetic fields through the magneto-optical waveguide (8) in the first micro-ring, it is transmitted to the first photodetector (13) through the first output straight waveguide (9). S4. z-axis and y-axis magnetic field sensing: The optical signal in the third transmission straight waveguide (6) is coupled into the micro-ring (10) on the second sensing chip. After sensing the z-axis and y-axis magnetic fields through the magneto-optical waveguide (11) in the second micro-ring, it is transmitted to the second photodetector (14) through the second output straight waveguide (12). S5. Three-dimensional magnetic field calculation: The first photodetector (13) and the second photodetector (14) convert the received optical signals into electrical signals, analyze the changes in the resonance peaks corresponding to the two electrical signals, and obtain the three-dimensional magnetic field strength of the x-axis, y-axis and z-axis by combining them.

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