阅读说明：本技术 一种基于高纯石英压力敏感元的光纤传感器及其制备方法 (Optical fiber sensor based on high-purity quartz pressure sensitive element and preparation method thereof ) 是由 王文华 吴伟娜 师文庆 熊正烨 付东洋 田秀云 谢玉萍 罗元政 赖学辉 费贤翔 于 2021-01-08 设计创作，主要内容包括：本发明公开一种基于高纯石英压力敏感元的光纤传感器及其制备方法,包括光纤、石英套管、高纯石英压力敏感元；石英套管内设有通孔,所述通孔内插入所述光纤；石英压力敏感元与石英套管连接。本发明能够适用于除氢氟酸和150℃以上的热磷酸以外的耐腐蚀等恶劣环境,因生物组织对石英材料不排斥所以也适用于颅内压的监测等应用；并通过激光热熔的方式免胶固定,能够提高稳定、可靠性和适用范围；石英压力敏感元的厚度由光学冷加工工艺控制,无需化学腐蚀等工艺,提高光纤传感头的稳定性、可靠性和寿命；本发明制作过程简单、快捷,传感器安全可靠、稳定性好,结合传统的光学冷加工工艺能够实现极小厚度的石英压力敏感元热熔。(The invention discloses an optical fiber sensor based on a high-purity quartz pressure sensitive element and a preparation method thereof, wherein the optical fiber sensor comprises an optical fiber, a quartz sleeve and the high-purity quartz pressure sensitive element; a through hole is arranged in the quartz sleeve, and the optical fiber is inserted into the through hole; the quartz pressure sensitive element is connected with the quartz sleeve. The invention can be suitable for the severe environment such as corrosion resistance except hydrofluoric acid and hot phosphoric acid with the temperature of more than 150 ℃, and is also suitable for monitoring intracranial pressure and the like because biological tissues do not exclude quartz materials; the laser hot melting mode is adopted for glue-free fixation, so that the stability, the reliability and the application range can be improved; the thickness of the quartz pressure sensitive element is controlled by an optical cold processing process, and processes such as chemical corrosion and the like are not needed, so that the stability, the reliability and the service life of the optical fiber sensing head are improved; the method has the advantages of simple and quick manufacturing process, safe and reliable sensor and good stability, and can realize the quartz pressure sensitive element hot melting with extremely small thickness by combining the traditional optical cold processing technology.)

1. An optical fiber sensor based on a high-purity quartz pressure sensitive element is characterized in that: comprises an optical fiber, a quartz sleeve and a high-purity quartz pressure sensitive element;

a through hole is formed in the quartz sleeve, and the optical fiber is inserted into the through hole; the quartz pressure sensitive element is connected with the quartz sleeve.

2. The optical fiber sensor based on the high-purity quartz pressure sensitive element according to claim 1, wherein: the quartz sleeve is internally provided with a through hole of a trapezoidal pit.

3. The optical fiber sensor based on the high-purity quartz pressure sensitive element according to claim 1, wherein: the quartz pressure sensitive element and the quartz sleeve are fixed in a laser hot melting mode without glue.

4. The fiber optic sensor based on high purity quartz pressure sensitive element of claim 3, wherein: before the quartz pressure sensitive element and the quartz sleeve are fixed in a laser hot melting mode without glue, the quartz pressure sensitive element needs to be temporarily fixed on the end face of the quartz sleeve by an optical glue method.

5. The optical fiber sensor based on the high-purity quartz pressure sensitive element according to claim 1, wherein:

the end face of the optical fiber and the inner surface of the quartz pressure sensitive element form a Fabry-Perot cavity.

6. The quartz pressure sensitive cell-based fiber optic sensor of claim 1, wherein:

the thickness of the pressure sensitive element of the quartz is controlled by an optical cold working process.

7. The preparation method of the optical fiber sensor based on the high-purity quartz pressure sensitive element according to any one of claims 1 to 6, characterized by comprising the following steps:

s1, selecting a quartz sleeve with the length of 6-8mm, processing the end face of the quartz sleeve by femtosecond laser, rapidly processing a regular and smooth trapezoidal pit, placing the processed quartz sleeve in an alcohol solution, ultrasonically cleaning for 2-5 minutes, repeatedly cleaning for 2-3 times, and finally drying for 1-2 hours at 100 ℃; the end face of the trapezoidal pit of the quartz sleeve is ground and polished by an optical cold machining process, the finish is not lower than 12 grade, the end face is ensured to be perpendicular to the axis of the sleeve, the verticality error is less than 1 degree, and finally, the polished end face is wiped clean by absolute ethyl alcohol;

s2, sanding and polishing one surface of the quartz pressure sensitive element, wherein the smoothness is 3-6 grades, sanding and polishing the other surface of the quartz pressure sensitive element to enable the smoothness to reach 12 grades or above 12 grades, simultaneously processing the thickness of the quartz pressure sensitive element to be the required thickness between 15 microns and 500 microns, and then wiping the sanded and polished pressure sensitive element clean by absolute alcohol;

s3, placing the quartz pressure sensitive element processed in the S2 in a thermostat at 300 ℃ for standing for 24 hours, and then carrying out annealing treatment of natural cooling;

s4, using CO for the quartz pressure sensitive element annealed in the S3₂Cutting the quartz sleeve into a square with the side length about 1.3 times of the diameter of the quartz sleeve by using laser, and wiping the quartz sleeve clean by using absolute alcohol;

s5, adsorbing the quartz pressure sensitive optical cement cut in the S4 to the end face of the quartz sleeve by utilizing the high smoothness of the glass surface;

s6, adsorbing the optical cement to the quartz pressure sensitive element on the end face of the quartz sleeve and fixing the edge close to the end face of the quartz sleeve by laser hot melting, and simultaneously using CO to fix the redundant quartz pressure sensitive element around the quartz sleeve₂Cutting off the wafer by laser, then placing the wafer in a thermostat at 300 ℃ for standing for 24-48 hours, and then naturally cooling the wafer for annealing treatment;

s7, designing the cavity length of a Fabry-Perot cavity of the standing sensor, and fixing the processed optical fiber into a quartz sleeve by adopting ultraviolet optical cement.

Technical Field

The invention relates to the field of fiber technology, Fabry-Perot interference and laser hot melting crossing of high-purity quartz, in particular to an optical fiber sensor based on a high-purity quartz pressure sensitive element and a preparation method thereof.

Background

The optical fiber sensor has the advantages of electric insulation, electromagnetic interference resistance, high sensitivity, high temperature resistance, corrosion resistance, small volume and light weight, is intrinsically safe due to the passive sensor end, can be remotely transmitted without signal conversion and an amplifier, has wide application prospect in the fields of communication, civil engineering, petrochemical engineering, aerospace and the like, and has great potential in middle and low voltage application occasions due to the fact that the pressure sensitive element can sense very small pressure in the Fabry-Perot optical fiber interference low-voltage sensor. In recent years, with the intensive research and application of the optical fiber low-voltage sensor, it is an interest of people to find the optical fiber low-voltage sensor which is simple, fast, safe, reliable, good in stability and capable of meeting the requirements of being used in various severe environments.

The Fabry-Perot fiber interference medium-low pressure sensor utilizes the self viscosity of an adhesive or a certain chemical material as a common method for constructing and fixing a pressure sensitive element of the sensor, fixes a silicon chip or the pressure sensitive element of the certain chemical material on the end surface of a conical opening of a capillary tube, and the like, but has the following defects: (1) after the optical fiber sensor is fixed by adopting the adhesives such as epoxy resin and the like, the thermal expansion coefficient of the adhesives can influence the temperature performance of the optical fiber sensor, and the optical fiber sensor can not be used at high temperature, can not meet the requirement of using the optical fiber sensor in severe environment, and can not exert the advantages of the optical fiber sensor; (2) when the pressure sensitive element is fixed on the end face of the capillary tube by using the self viscosity of a certain chemical material, the pressure sensitive element is easy to fall off from the end face after the sensor is subjected to the action of ultrasonic waves or other strong vibration signals, so that the optical fiber sensor is completely ineffective, and the use in a high-temperature severe environment cannot be met; (3) if the pressure sensitive element is quartz pressure sensitive element, the pressure sensitive element is fixed by gluing in a common mode at present, but the adhesive is easy to age, the thermal expansion coefficient of the adhesive is much larger than that of quartz, so that the performance of the sensor such as working point drift and the like is deteriorated or failed, meanwhile, the adhesive cannot bear the use in a high-temperature environment, the pressure sensitive element is easy to loosen or fall off due to the corrosion in a severe environment, and biological tissues do not reject quartz materials, so that the pressure sensitive element is suitable for monitoring intracranial pressure and the like.

Disclosure of Invention

The invention aims to provide an optical fiber sensor based on a high-purity quartz pressure sensitive element and a preparation method thereof, which are used for solving the problems in the prior art, have simple and quick manufacturing process, are safe, reliable and good in stability, can realize the hot melting of the quartz pressure sensitive element with extremely small thickness by combining the traditional optical cold processing technology, are suitable for various severe environments except hydrofluoric acid and hot phosphoric acid with the temperature of more than 150 ℃, and are also suitable for monitoring intracranial pressure and the like because biological tissues do not exclude quartz materials.

In order to achieve the purpose, the invention provides the following scheme: an optical fiber sensor based on a high-purity quartz pressure sensitive element comprises an optical fiber, a quartz sleeve and a high-purity quartz pressure sensitive element;

a through hole is formed in the quartz sleeve, and the optical fiber is inserted into the through hole; the quartz pressure sensitive element is connected with the quartz sleeve.

Preferably, a through hole of a trapezoidal pit is arranged in the quartz sleeve;

preferably, the quartz pressure sensitive element and the quartz sleeve are fixed in a laser hot melting mode without glue.

Preferably, before the quartz pressure sensitive element and the quartz sleeve are fixed in a laser hot melting mode without glue, the quartz pressure sensitive element needs to be temporarily fixed on the end face of the quartz sleeve by a method of optical glue.

Preferably, the end face of the optical fiber and the inner surface of the quartz pressure sensitive element form a Fabry-Perot cavity.

Preferably, the thickness of the pressure sensitive element of the quartz is controlled by an optical cold working process.

A preparation method of an optical fiber sensor based on a high-purity quartz pressure sensitive element comprises the following steps:

s1, selecting a quartz sleeve with the length of 6-8mm, processing the end face of the quartz sleeve by femtosecond laser, rapidly processing a regular and smooth trapezoidal pit, placing the processed quartz sleeve in an alcohol solution, ultrasonically cleaning for 2-5 minutes, repeatedly cleaning for 2-3 times, and finally drying for 1-2 hours at 100 ℃; the end face of the trapezoidal pit of the quartz sleeve is ground and polished by an optical cold machining process, the finish is not lower than 12 grade, the end face is ensured to be perpendicular to the axis of the sleeve, the verticality error is less than 1 degree, and finally, the polished end face is wiped clean by absolute ethyl alcohol;

s2, sanding and polishing one surface of the quartz pressure sensitive element, wherein the smoothness is 3-6 grades, sanding and polishing the other surface of the quartz pressure sensitive element to enable the smoothness to reach 12 grades or above 12 grades, simultaneously processing the thickness of the quartz pressure sensitive element to be the required thickness between 15 microns and 500 microns, and then wiping the sanded and polished pressure sensitive element clean by absolute alcohol;

s3, placing the quartz pressure sensitive element processed in the S2 in a thermostat at 300 ℃ for standing for 24 hours, and then carrying out annealing treatment of natural cooling;

s4, using CO for the quartz pressure sensitive element annealed in the S3₂Cutting the quartz sleeve into a square with the side length about 1.3 times of the diameter of the quartz sleeve by using laser, and wiping the quartz sleeve clean by using absolute alcohol;

s5, adsorbing the quartz pressure sensitive optical cement cut in the S4 to the end face of the quartz sleeve by utilizing the high smoothness of the glass surface;

s6, adsorbing the optical cement to the quartz pressure sensitive element on the end face of the quartz sleeve and fixing the edge close to the end face of the quartz sleeve by laser hot melting, and simultaneously using CO to fix the redundant quartz pressure sensitive element around the quartz sleeve₂Cutting off the wafer by laser, then placing the wafer in a thermostat at 300 ℃ for standing for 24-48 hours, and then naturally cooling the wafer for annealing treatment;

s7, designing the cavity length of a Fabry-Perot cavity of the standing sensor, and fixing the processed optical fiber into a quartz sleeve by adopting ultraviolet optical cement.

Compared with the prior art, the invention has the following technical effects:

(1) the optical fiber sensor adopts the all-quartz material, can be suitable for corrosion-resistant severe environments except hydrofluoric acid and hot phosphoric acid with the temperature of more than 150 ℃, and is also suitable for monitoring intracranial pressure and the like because biological tissues do not exclude the quartz material;

(3) the thickness of the quartz pressure sensitive element is controlled by an optical cold processing technology, and chemical corrosion and other technologies are not needed, so that the stability, reliability and service life of the optical fiber sensing head are improved;

(4) the method has the advantages of simple and quick manufacturing process, safe and reliable sensor and good stability, and can realize the quartz pressure sensitive element hot melting with extremely small thickness by combining the traditional optical cold processing technology.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of an optical fiber sensor based on a quartz pressure sensitive element according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Example 1

Referring to fig. 1, the invention provides an optical fiber sensor based on a quartz pressure sensitive element, which comprises an optical fiber, a quartz sleeve with a trapezoidal pit, and a thin quartz pressure sensitive element, wherein the optical fiber sensor is made of a full quartz material and is suitable for the severe environments such as corrosion resistance except hydrofluoric acid and hot phosphoric acid with the temperature of more than 150 ℃; the thickness of the quartz pressure sensitive element is controlled by an optical cold processing technology, and chemical corrosion and other technologies are not needed, so that the stability, reliability and service life of the optical fiber sensing head are improved; when the external static or dynamic pressure change acts on the glass pressure sensitive element, the cavity length of the Fabry-Perot cavity is changed, and the external pressure change information is demodulated according to the cavity length change information.

The preparation method of the optical fiber sensor based on the quartz pressure sensitive element comprises the following steps:

selecting a quartz sleeve with the length of 6-8mm, processing the end face of the quartz sleeve by using femtosecond laser, rapidly processing a regular and smooth trapezoidal pit so as to insert an optical fiber and form a Fabry-Perot cavity of a sensor, placing the processed quartz sleeve in an alcohol solution, ultrasonically cleaning for 2-5 minutes, repeatedly cleaning for 2-3 times, and finally drying for 1-2 hours at 100 ℃; the end face of the trapezoidal pit of the quartz sleeve is ground and polished by an optical cold machining process, the finish is not lower than 12 grade, the end face is ensured to be perpendicular to the axis of the sleeve, the verticality error is less than 1 degree, and finally, the polished end face is wiped clean by absolute ethyl alcohol;

sanding and polishing one surface of the quartz pressure sensitive element, wherein the degree of finish is 3-6 grades, sanding and polishing the other surface of the quartz pressure sensitive element to ensure that the degree of finish reaches 12 grades or above 12 grades, simultaneously processing the thickness of the quartz pressure sensitive element to the required thickness between 15 microns and 500 microns, and then wiping the sanded and polished pressure sensitive element clean by absolute alcohol;

placing the quartz pressure sensitive element processed in the step two in a thermostat at 300 ℃ for standing for 24 hours, and then carrying out annealing treatment of natural cooling to release internal residual stress generated by the ultrathin quartz pressure sensitive element in the sanding and polishing process and reduce the probability of cracks and fissures generated by the ultrathin pressure sensitive element in the laser hot melting process;

step four, utilizing CO to the quartz pressure sensitive element processed in the step three₂Cutting the quartz sleeve into a square with the side length about 1.3 times of the diameter of the quartz sleeve by using laser, and wiping the square by using absolute alcohol;

absorbing the pressure sensitive element optical cement cut in the fourth step to the end face of the quartz sleeve by utilizing the high smoothness of the glass surface;

step six, adsorbing the optical cement to a quartz pressure sensitive element on the end face of the quartz sleeve and using laser to enable the edge close to the end face of the quartz sleeve to be close toFixing by hot melting, and simultaneously using CO for redundant quartz pressure sensitive elements around the quartz sleeve₂Cutting off the laser, then placing the cut glass in a thermostat at 300 ℃ for standing for 24-48 hours, naturally cooling the glass along with the cut glass to carry out annealing treatment, and releasing internal residual stress generated by hot melting;

and seventhly, designing the cavity length of the Fabry-Perot cavity of the standing sensor, and fixing the processed optical fiber into the quartz sleeve by gluing.

The invention has simple and rapid manufacturing process, safe and reliable sensor and good stability, can realize quartz pressure sensitive element hot melting with extremely small thickness by combining the traditional optical cold processing technology, and is suitable for various severe environments except hydrofluoric acid and hot phosphoric acid with the temperature of more than 150 ℃.

In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, are merely for convenience of description of the present invention, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.