CN111579847A - Double-enhancement current sensing system based on micro fiber junctions and magnetic fluid - Google Patents

Abstract

The invention proposes a dual-enhanced current sensing system based on microfiber junctions and magnetic fluids. The optical signal output by the broadband light source of the invention enters the optical fiber resonant cavity through the optical fiber connection, and the optical field entering the resonant cavity is transmitted and then output into the spectrometer for Observe that the copper wire that generates the current signal is firmly in contact with the outer diameter of the optical fiber resonator; the broadband light source and the optical fiber, the optical fiber resonator and the spectrometer are connected by an optical fiber, and the resonator is fixed in the magnetic fluid by a low-refractive-index UV-curing glue , the position of the resonant cavity, the magnetic fluid and the optical fiber resonant cavity is fixed, and the refractive index value of the low-refractive-index UV-curing glue should ensure that the optical field transmits without loss in the resonant cavity. The invention has the advantages of low cost, low power consumption, small size, high precision, easy integration, and high precision detection of current signals.

Description

Dual-enhanced current sensing system based on microfiber junction and magnetic fluid

technical field

The invention relates to a high-precision sensing system based on magnetic fluid current measurement, in particular to a current sensing system constructed by a magnetic fluid material and an optical resonant cavity, which belongs to the field of optics.

Background technique

Microfibers have attracted extensive attention due to their unique optical properties, and many research efforts have been aimed at developing microfiber-based optical resonators and many potential applications, including tunable fiber lasers and optical fiber sensors. In this paper, a dual-enhanced current sensing system based on microfiber junctions and magnetic fluid is proposed. On the basis of the existing current sensing, the current sensing sensitivity is simultaneously improved by comprehensively utilizing the temperature change and the external magnetic fluid, which can be widely used. Used in defense, aerospace, automotive electronics, medical, energy, consumer electronics, industrial control and other fields.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the prior art, the present invention proposes a dual-enhanced current sensing system based on microfiber junctions and magnetic fluid, which can be used in the field of current signal detection requiring high-sensitivity measurement and low-frequency current detection capability.

A dual-enhanced current sensing system based on a microfiber junction and a magnetic fluid, comprising a broadband light source, an optical fiber resonant cavity, a magnetic fluid, a low-refractive-index UV-curable glue, and a spectrometer;

The optical signal output by the broadband light source is sent into the input port of the optical fiber resonant cavity through the optical fiber, and the optical field in the optical fiber resonant cavity is transmitted to the spectrometer through the optical fiber after multiple transmissions. The outer side of the optical fiber resonant cavity; the outer side of the optical fiber resonant cavity is provided with a copper wire connected with direct current, and the optical fiber resonant cavity is formed by knotting microfibers; the copper wire connected with the direct current changes the external magnetic field, and the This leads to a change in the refractive index of the magnetic fluid, which in turn leads to a change in the effective refractive index of the fiber resonator, that is, the optical path, and the current signal flowing through the copper wire will cause a temperature change, which in turn changes the resonant frequency of the optical signal in the fiber resonator. The refractive index and optical path length of the optical fiber resonator are changed, so the transmission spectrum of the cavity measured on the spectrometer will contain current information, and the intensity information of the current can be demodulated through data processing; the resonant cavity is resonated with the magnetic fluid and the optical fiber. The position of the cavity is fixed; the refractive index value of the low-refractive-index UV-curable adhesive should ensure that the optical field transmits without loss in the resonant cavity.

Preferably, the magnetic fluid is a colloidal solution containing Fe ₃ O ₄ , or other magnetic materials whose refractive index can be changed under the action of a magnetic field are selected.

Preferably, the method for improving the current sensing sensitivity is to change the wavelength shift in the cavity caused by the heat released by the current flowing through the copper wire, and to add a magnetic fluid to increase the sensing accuracy.

Preferably, the effect of heat on the parameters of the resonant cavity is controlled by adjusting the magnitude of the current flowing through the copper wire.

Preferably, the resonant cavity is formed by knotting silicon fibers prepared by flame brush technology.

Preferably, the optical fiber resonant cavity is embedded in the magnetic fluid, or the resonant cavity is pasted on the magnetic fluid.

Preferably, the resonant cavity material is silicon microfiber material, and the shape is a ring cavity or a microsphere cavity; the resonant cavity should be able to support light wave transmission, and an evanescent wave exists on the outer surface of the cavity.

Preferably, the shape of the magnetic fluid is a cylinder, a flat plate or a helmet.

Preferably, the microfiber coupling length is at least 3 mm to obtain sufficient van der Waals forces to connect the two microfibers together.

Preferably, the optical fiber should ensure low-loss transmission and easy detection of optical signals in the selected wavelength band.

Preferably, the optical fiber resonant cavity is replaced with a double-ring resonator cavity with an embedded microcavity.

The current sensing system in the present invention comprehensively utilizes temperature and magnetic fluid to detect current signals, and has high sensing sensitivity. At the same time, the system is mainly constructed of optical fiber, which is small in size and easy to integrate, and can perform remote detection of current information.

Description of drawings

FIG. 1 is a schematic structural diagram of an invented dual-enhanced current sensing system based on microfiber junctions and magnetic fluid;

Detailed ways

The substantive features and significant progress of the present invention are further illustrated below by specific embodiments, but the content of the present invention is not limited to the following embodiments:

As shown in FIG. 1 , the dual-enhanced current sensing system based on microfiber junctions and magnetic fluid described in this embodiment includes a broadband light source 1 , an optical fiber resonant cavity 2 , a magnetic fluid 3 , a low-refractive-index UV-curable glue 4 , and a spectrometer 5 . Among them, the optical signal output by the broadband light source 1 is sent into the input port of the optical fiber resonant cavity 2 through the optical fiber, and the optical field in the cavity is transmitted to the spectrometer 5 through the optical fiber after multiple transmissions. Around the outside of the cavity, the change of the external magnetic field will cause the change of the refractive index of the magnetic fluid 3, which will lead to the change of the effective refractive index of the resonant cavity 2, that is, the change of the optical path. The resonant frequency of the optical signal in the cavity 2 affects the refractive index and optical path length of the optical fiber resonant cavity. Therefore, the transmission spectrum of the cavity measured on the spectrometer 5 will contain current information, and the intensity information of the current can be demodulated through data processing. . The resonant cavity 2 can be replaced with a double-ring resonator cavity, an embedded microcavity or a microcavity of other shapes, as long as the size is close, and the light field output by the light source can be transmitted in it with low loss, and there is an evanescent on the outer surface of the cavity. Wave. Design according to specific application scenarios and actual intensity detection requirements, as long as the transmission characteristics can be changed under the action of the current signal.

Claims (10)

1. A dual-enhanced current sensing system based on a microfiber junction and a magnetic fluid, which is characterized in that it includes a broadband light source (1), an optical fiber resonant cavity (2), a magnetic fluid (3), and a low-refractive-index UV-curable glue (4) , spectrometer (5); The optical signal output by the broadband light source (1) is sent into the input port of the optical fiber resonant cavity (2) through the optical fiber, and the optical field in the optical fiber resonant cavity is transmitted to the spectrometer (5) through the optical fiber after multiple transmissions. The ultraviolet curing glue (4) fixes the magnetic fluid (3) on the outer side of the optical fiber resonant cavity (2). (2) It is formed by knotting microfibers; the change of the external magnetic field caused by the copper wire with direct current will cause the refractive index of the magnetic fluid (3) to change, which will lead to the effective refractive index of the optical fiber resonant cavity (2), that is, the light When the optical path changes, the current signal flowing through the copper wire will cause a temperature change, which in turn changes the resonant frequency of the optical signal in the optical fiber resonator (2), thereby affecting the refractive index and optical path length of the optical fiber resonator. Therefore, the spectrometer (5) ) will contain current information in the transmission spectrum of the cavity measured on the The refractive index value of the cured adhesive should ensure that the optical field transmits without loss in the resonant cavity. 2. The dual-enhanced current sensing system based on microfiber junctions and magnetic fluid according to claim 1, wherein the magnetic fluid is a colloidal solution containing Fe ₃ O ₄ , or other selected ones under the action of a magnetic field A magnetic material capable of changing its refractive index. 3. The dual-enhanced current sensing system based on microfiber junction and magnetic fluid according to claim 1, wherein the method for improving the sensitivity of current sensing is the heat released by the current flowing through the copper wire Induced changes in the wavelength shift in the cavity, and the addition of magnetic fluid increases the sensing accuracy. 4 . The dual-enhanced current sensing system based on microfiber junction and magnetic fluid according to claim 1 , wherein the influence of heat on the parameters of the resonant cavity is controlled by adjusting the magnitude of the current flowing through the copper wire. 5 . 5 . The dual-enhanced current sensing system based on microfiber knots and magnetic fluid according to claim 1 , wherein the resonant cavity is formed by knotting silicon fibers prepared by flame brush technology. 6 . 6 . The dual-enhanced current sensing system based on microfiber knots and magnetic fluid according to claim 1 , wherein the optical fiber resonant cavity is embedded in the magnetic fluid, or the resonant cavity is pasted on the magnetic fluid. 7 . 7. The dual-enhanced current sensing system based on microfiber junction and magnetic fluid according to claim 1, wherein the resonant cavity material is silicon microfiber material, and the shape is a ring cavity or a microsphere cavity; The cavity should be able to support light wave transmission, and there should be evanescent waves on the outer surface of the cavity. 8. The dual-enhanced current sensing system based on microfiber junctions and magnetic fluid according to claim 1, wherein the magnetic fluid is in the shape of a cylinder, a flat plate or a helmet. 9. The dual-enhanced current sensing system based on a microfiber junction and a magnetic fluid according to claim 1, wherein the microfiber coupling length is at least 3 mm, in order to obtain sufficient van der Waals force to connect the two microfibers on the Together. 10 . The dual-enhanced current sensing system based on a microfiber junction and a magnetic fluid according to claim 1 , wherein the optical fiber resonant cavity is replaced with a double-ring resonant cavity and an embedded microcavity. 11 .

Images