CN101852840A - A kind of optical fiber FAPP magnetic field sensor and preparation method thereof - Google Patents

Abstract

The invention discloses an optical fiber Fabry-Perot magnetic field sensor, which comprises optical fiber and is characterized in that a Fabry-Perot cavity which uses gas or air as medium is arranged on one end surface of the optical fiber, the Fabry-Perot cavity comprises two reflecting surfaces, one reflecting surface is the end surface of the optical fiber, the other reflecting surface is a diaphragm corresponding to the end surface of the optical fiber, the diaphragm is plated or stuck with magnetic material or metal material, when the diaphragm gets close to a magnetic field, magnetic force drives the diaphragm to move to change the length of the Fabry-Perot cavity, and the optical fiber picks up the reflective optical signal of the Fabry-Perot cavity to obtain the length information of the length of the Fabry-Perot cavity to realize the measurement of the magnetic field. The invention has the advantages that the sensor overcomes the defects of the prior art, the long-term, stable and accurate measurement of the magnetic field can be realized, the sensitivity is high and the preparation method is simple.

Description

A kind of optical fiber FAPP magnetic field sensor and preparation method thereof

technical field

The invention relates to the technical field of optical fiber sensing, in particular to an optical fiber FAPO magnetic field sensor and a preparation method thereof.

Background technique

Magnetic field measurement is an important branch of electromagnetic measurement technology. Magnetic field measurement is involved in many fields of industrial production and scientific research. Such as: current measurement, magnetic prospecting, maglev train, geological exploration, isotope separation, mass spectrometer, electron beam and ion beam processing device, controlled thermonuclear reaction, and artificial earth satellite, etc., and even has applications in medicine and biology. For example, magnetic field therapy to treat diseases, use "magnetocardiogram" and "magnetoencephalogram" to diagnose diseases, the effect of environmental magnetic field on organisms and human body, and the research of magnetic phenomena and life phenomena all require magnetic field measurement technology and magnetic measuring instruments Therefore, the measurement technology of magnetic field is closely related to people's life.

Traditional magnetic field sensors are mainly based on electrical testing principles, such as Hall effect and electromagnetic induction principles, and mature products have already been produced. However, sensors based on the principle of electric measurement are often susceptible to electromagnetic interference and magnetic saturation, so optical magnetic field sensors are attracting more and more attention. The existing optical magnetic field sensors are mainly based on the Faraday rotation effect or the principle of magneto-mechanical-optical conversion, which have disadvantages such as poor long-term stability and low measurement accuracy.

Contents of the invention

The problem to be solved by the present invention is: how to provide an optical fiber FAPO magnetic field sensor and its preparation method, the sensor can overcome the defects of the prior art, can realize long-term stable and accurate magnetic field measurement, and has high sensitivity and simple preparation method.

The technical problem proposed by the present invention is solved in the following way: provide a kind of optical fiber enamel magnetic field sensor, comprise optical fiber, it is characterized in that, a enamel cavity with gas or air as medium is set on one end face of optical fiber, said enamel The cavity includes two reflective surfaces, one reflective surface is the end face of the optical fiber, and the other reflective surface is a diaphragm corresponding to the end face of the optical fiber. The diaphragm is coated or pasted with magnetic materials or metal materials. The diaphragm moves to change the cavity length of the FAPO cavity, and the optical fiber picks up the reflected optical signal of the FAPO cavity to obtain the cavity length information of the FAPO cavity to realize the measurement of the magnetic field.

According to the optical fiber FAPO magnetic field sensor provided by the present invention, it is characterized in that the cross section of the FAPO cavity is greater than, equal to or smaller than the cross section of the fiber core of the optical fiber.

According to the fiber optic FAPO magnetic field sensor provided by the present invention, the FAPO cavity is composed of a cylindrical microgroove arranged in the center of the fiber end face and a diaphragm butted on the fiber end face.

According to the optical fiber FAP magnetic field sensor provided by the present invention, the FAP cavity is composed of the end face of the optical fiber, a sleeve sleeved on the optical fiber and a diaphragm arranged at the other end of the sleeve.

According to the optical fiber FAP magnetic field sensor provided by the present invention, it is characterized in that the optical fiber is a single-mode optical fiber made of quartz, polymer, gemstone or photonic crystal material.

A kind of preparation method of optical fiber enamel magnetic field sensor, it is characterized in that, comprises the following steps:

①Use a 157nm laser to process a cylindrical microgroove on the end face of the optical fiber, with a depth between 10μm and 10mm;

② Butt a diaphragm of the same material on the outside of the cylindrical microgroove to form a enamel cavity;

③The magnetic material or metal material is plated on the diaphragm to make a fiber-optic F-P magnetic field sensor.

A kind of preparation method of optical fiber enamel magnetic field sensor, it is characterized in that, comprises the following steps:

① Cut the two ends of the sleeve flat, and the inner circle of the sleeve can be used to sleeve the optical fiber;

② Butt a diaphragm of the same material as the casing at one end of the casing;

③ Coat the surface of the diaphragm with magnetic material or metal material, insert the optical fiber into the sleeve, and keep a small distance from the diaphragm, and fix it with glue to make a fiber optic F-P magnetic field sensor.

The working principle of the present invention is: to set a FAPO chamber with gas or air as the medium and including two optical reflection surfaces, one end of the FAPO chamber is a diaphragm, and the magnetic material or metal is plated or pasted on the diaphragm. Material, diaphragm and magnetic (metallic) material thickness and FP cavity size are adjustable for sensitivity. Close to the magnetic field, the magnetic field of the magnetic (metal) material and the magnetic field perpendicular to the diaphragm produce a magnetic force, and the magnetic force drives the diaphragm to move to change the length of the FP cavity. The optical fiber is used to pick up the reflected optical signal of the FP cavity to obtain the cavity length information, which can be realized. Measurement of magnetic fields.

The invention has a simple and reasonable structure, can realize long-term stable and accurate magnetic field measurement, and has high sensitivity, and the realization method is also very simple.

Description of drawings

Fig. 1 is the structural representation of first kind of embodiment of the present invention;

Fig. 2a is a schematic structural view of the second embodiment of the present invention, wherein Fig. 2b is a schematic view of the right end face of Fig. 2a;

Fig. 3 is the structural representation of the third embodiment of the present invention;

Fig. 4a is a schematic structural diagram of a fourth embodiment of the present invention, wherein Fig. 4b is a schematic diagram of the right side end of Fig. 4a.

Among them, 1. Optical fiber, 2. Diaphragm, 3. Fabric cavity, 4. Magnetic material layer, 5. Sleeve, 6. Glue layer, 7. Metal layer.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing:

As shown in Figures 1 to 4, the optical fiber FAPP magnetic field sensor includes an optical fiber 1, and a FAPO cavity 3 with gas or air as a medium is arranged on one end of the fiber 1. The FAPO cavity 3 includes two reflecting surfaces, one The reflective surface is the end face of the optical fiber, and the other reflective surface is the diaphragm 2 corresponding to the end face of the optical fiber. The diaphragm 2 is coated or pasted with a magnetic material layer 4 or a metal layer 7. When it is close to the magnetic field, the magnetic force drives the diaphragm to move and change The cavity length of the FAPO cavity, the optical fiber picks up the reflected optical signal of the FAPO cavity to obtain the cavity length information of the FAPO cavity, and realizes the measurement of the magnetic field.

The optical fiber 1 of the present invention is a single-mode optical fiber made of quartz, polymer, gem or photonic crystal material, and the processing described in the present invention is to use 157nm laser processing, femtosecond laser processing, infrared laser processing or electron beam etching , the butt joint of the present invention adopts laser welding, arc welding, or bonding, and the cutting of the present invention adopts laser, cutting knife or grinding method to cut off. The optical fiber of the present invention is composed of a cladding and a core, and the cross section of the FPP cavity may be greater than, equal to or smaller than that of the core of the optical fiber.

Example 1

Including the optical fiber 1, a cylindrical microgroove is set on one end of the optical fiber 1, and the depth is between 10 μm and 10 mm, and the membrane 2 corresponding to the end surface of the optical fiber is connected outside the cylindrical microgroove to form a enamel cavity 3, and the membrane 2 A magnetic material or a metal material layer is plated or pasted. The preparation method is: ① use a 157nm laser to process a cylindrical microgroove on the end face of the optical fiber, with a depth between 10 μm and 10 mm; ② connect a diaphragm of the same material to the outside of the cylindrical microgroove to form a enamel cavity; ③ The magnetic material 4 or the metal material 7 is plated on the diaphragm to form an optical fiber Fappaut magnetic field sensor.

Example 2

Including the optical fiber 1, a enamel chamber 3 with gas or air as the medium is arranged on one end face of the optical fiber 1. 5 The diaphragm 2 at the other end is formed, and the diaphragm 2 is plated or pasted with a magnetic material or a metal material layer. The preparation method is as follows: ① cut the two ends of the sleeve 5 flat, and the inner circle of the sleeve 5 can be sleeved with the optical fiber 1; ② connect one end of the sleeve 5 with a diaphragm 2 of the same material as the sleeve 5; 2. Coat the surface with magnetic material 4 or metal material layer 7, insert the optical fiber 1 into the sleeve 5, and keep a small distance from the diaphragm 2, and fix it with a glue layer 6 to make an optical fiber Perot magnetic field sensor.

Claims (7)

1. An optical fiber enamel magnetic field sensor, comprising an optical fiber, is characterized in that an end face of the optical fiber is provided with a enamel cavity with gas or air as a medium, and the enamel cavity includes two reflective surfaces, and a reflective surface is The end face of the optical fiber, and the other reflective surface is a diaphragm corresponding to the end face of the optical fiber. The diaphragm is coated or pasted with magnetic materials or metal materials. When it is close to the magnetic field, the magnetic force drives the diaphragm to move to change the Cavity length, the optical fiber picks up the reflected optical signal of the FAPO cavity to obtain the cavity length information of the FAPO cavity, and realizes the measurement of the magnetic field. 2 . The fiber optic FAP magnetic field sensor according to claim 1 , wherein the cross section of the FAP cavity is greater than, equal to or smaller than the cross section of the fiber core of the optical fiber. 3 . 3. The fiber optic FAP magnetic field sensor according to claim 2, wherein the FAP cavity is composed of a cylindrical microgroove arranged in the center of the fiber end face and a diaphragm connected to the fiber end face. 4. The fiber optic FAP magnetic field sensor according to claim 2, characterized in that, the FAP cavity is composed of the end face of the optical fiber, a sleeve sleeved on the optical fiber and a diaphragm arranged at the other end of the sleeve. 5 . The optical fiber FAP magnetic field sensor according to any one of claims 1 to 4 , wherein the optical fiber is a single-mode optical fiber made of quartz, polymer, gem or photonic crystal material. 6. the preparation method of optical fiber enamel magnetic field sensor according to claim 3, is characterized in that, comprises the following steps: ①Use a 157nm laser to process a cylindrical microgroove on the end face of the optical fiber, with a depth between 10μm and 10mm; ② Butt a diaphragm of the same material on the outside of the cylindrical microgroove to form a enamel cavity; ③The magnetic material or metal material is plated on the diaphragm to make a fiber-optic F-P magnetic field sensor. 7. the preparation method of optical fiber enamel magnetic field sensor according to claim 4, is characterized in that, comprises the following steps: ① Cut the two ends of the sleeve flat, and the inner circle of the sleeve can be used to sleeve the optical fiber; ② Butt a diaphragm of the same material as the casing at one end of the casing; ③ Coat the surface of the diaphragm with magnetic material or metal material, insert the optical fiber into the sleeve, and keep a small distance from the diaphragm, and fix it with glue to make a fiber optic F-P magnetic field sensor.

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