A fully automatic manufacturing device and method for optical fiber FP cavity sensor

Abstract

The present invention relates to the technical field of optical fiber sensors, and in particular discloses a fully automatic manufacturing device and manufacturing method for an optical fiber F-P cavity sensor. The fully automatic manufacturing device for an optical fiber F-P cavity sensor comprises a device bracket, a capillary glass tube fixing fixture is installed on the upper end of the device bracket, a collimating glass tube is fixed on the capillary glass tube fixing fixture, the capillary glass tube passes through the collimating glass tube and is fixed on the capillary glass tube fixing fixture, a signal optical fiber and a reflection optical fiber are arranged in the capillary glass tube, and the capillary glass tube is characterized in that: a straightening system is installed on the capillary glass tube, and a spectrum monitoring system is connected to the signal optical fiber inside the capillary glass tube. The present invention significantly improves the consistency and stability of welding through an intelligent control method, greatly reduces the dependence on the skill level of the operator, and effectively reduces the workload of the operator.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber sensors, and in particular to a fully automatic manufacturing device and method for an optical fiber FP cavity sensor. Background Art

[0002] With the rapid development of fiber-optic communication technology, fiber-optic sensing technology has also received widespread attention and application. Fiber-optic sensing technology has the advantages of high sensitivity, long-distance transmission and anti-interference, so it has become a hot topic of research. The fiber-optic Fabry-Perot cavity (FP cavity for short) sensor is a sensor designed and implemented based on the principle of fiber-optic interference. The fiber-optic FP cavity sensor has the advantages of high sensitivity, fast response, long-distance transmission and anti-interference. It has a simple structure and low preparation cost. It can measure a variety of physical quantities such as temperature, pressure, strain, sound waves, vibration, etc. Therefore, it has broad application prospects in the fields of industry, medical treatment, environmental monitoring, etc.

[0003] The traditional method of making a fiber FP cavity is to insert two bare optical fibers with flat end faces into a collimating capillary with an inner diameter matching the two bare optical fiber end faces and the air cavity between them to form a fiber FP cavity. The first key point is how to achieve reliable fixation of the bare optical fiber and the capillary. Generally, epoxy resin glue is used for bonding, which is unstable at high temperature and has creep, resulting in unstable fiber FP cavity length and poor sensor performance. The traditional high-temperature fiber fusion method based on hydrogen-oxygen flame has uncontrollable parameters during the production process. The fiber fusion method based on electrode discharge heating is circumferential local heating during the heating process, and it is impossible to achieve full circumferential fusion. The fiber fusion method based on CO2 laser is also circumferential local heating, which makes the fusion point unevenly stressed and the cost is very high. The second key point is how to control the FP cavity length and realize real-time spectral monitoring during the production process. In the existing fiber FP cavity sensor production technology, a significant problem is that when using hydrogen-oxygen flame high-temperature hot melting technology for fusion, the state of the optical fiber cannot be monitored, resulting in difficulty in regulating the flame size. This process is highly dependent on manual operation, which places extremely high demands on the professional skills and experience of the operator, affecting production efficiency and thus affecting the overall performance of the sensor.

[0004] Chinese patent CN103644925A discloses a method and device for making an optical fiber FP cavity sensor, which uses hydrogen and oxygen to heat a hot-melt capillary glass tube to melt the capillary glass tube wall, and at the same time, under the action of vacuum, the capillary glass tube wall collapses inward and fuses with the optical fiber. During the application process, the device uses a monitoring computer to monitor the cavity length, but it can only play a monitoring role and cannot provide real-time feedback and adjustment of parameters.

[0005] In summary, the adhesive bonding method has creep when the temperature changes, and the FP cavity length is unstable; the traditional high-temperature welding method has the disadvantages of uncontrollable parameters and uneven force at the welding point. At the same time, there is no capillary straightening device. Since the high temperature needs to reach the melting point of the material, the capillary will deform at high temperature and the sensor performance is poor; and both methods lack the FP cavity length control device and the real-time spectral monitoring device during the production process.

[0006] The traditional fiber FP cavity probe manufacturing device and method have the problems of low efficiency, uncontrollable parameters, and difficult to ensure accuracy. Therefore, it is particularly important to develop a fully automatic, parameter-controllable, real-time monitoring, and low-cost fiber FP cavity sensor manufacturing technology. Summary of the invention

[0007] In order to make up for the deficiencies of the prior art, the present invention provides a fully automatic manufacturing device and method for an optical fiber FP cavity sensor which has the advanced function of integrating a spectrometer to monitor light reflection and transmittance, effectively prevents the bending phenomenon that may occur in the FP cavity during the welding process, and improves the manufacturing quality and reliability of the probe.

[0008] The present invention is achieved through the following technical solutions:

[0009] A fully automatic manufacturing device for an optical fiber FP cavity sensor comprises a device support, a capillary glass tube fixing fixture is installed on the upper end of the device support, a collimating glass tube is fixed on the capillary glass tube fixing fixture, the capillary glass tube passes through the collimating glass tube and is fixed on the capillary glass tube fixing fixture, a signal optical fiber and a reflection optical fiber are arranged in the capillary glass tube, and the feature is that: a straightening system is installed on the capillary glass tube, and a spectrum monitoring system is connected to the signal optical fiber inside the capillary glass tube;

[0010] The straightening system comprises an annular jet valve sleeved on the periphery of the capillary glass tube, a CCD microscope is fixed directly above the annular jet valve, the CCD microscope signal is connected to the control system, the control system signal is connected to the adjustable power supply of the air pump, and the air pump is connected to the annular jet valve through a ventilation pipe;

[0011] The spectrum monitoring system comprises an ASE light source connected to a 1×N coupler, one optical fiber of the 1×N coupler is connected to an A / D converter as a wavelength calibration channel, multiple optical fibers of the 1×N coupler are connected in parallel to a plurality of 3DB directional couplers, the 3DB directional coupler is connected to a signal optical fiber interface of a capillary glass tube via a transmission optical fiber, and a reflection optical fiber of the capillary glass tube is connected to the 3DB directional coupler, a reflection signal of the 3DB directional coupler passes through the A / D converter, and the A / D converter is connected to a display of a control system;

[0012] The reflecting optical fiber is clamped and fixed by a five-dimensional translation stage, the hydrogen-oxygen flame high-temperature hot melting device is installed around the capillary glass tube through a moving device, and a timing device and a fuel proportioning device are arranged in the hydrogen-oxygen flame high-temperature hot melting device, and the five-dimensional translation stage, the moving device, the timing device and the fuel proportioning device are all connected to the spectral monitoring system.

[0013] Based on the existing optical fiber FP cavity sensor manufacturing device, the present invention optimizes the hydrogen-oxygen flame high-temperature hot melting device and introduces a parameter controllable device. Before welding, the PID algorithm can dynamically adjust the cavity length of the FP cavity in real time in combination with the data fed back by the spectrometer to achieve the best spectral contrast. In addition, the present invention realizes a significant improvement in welding accuracy by real-time monitoring of the spectral image during the welding process and determining the key optimal parameters such as temperature and time in the welding process after testing.

[0014] A better technical solution of the present invention is:

[0015] The center of the annular jet valve coincides with the center of the capillary glass tube, and the inner diameter of the annular jet valve is slightly larger than the outer diameter of the capillary glass tube, so that the annular jet valve and the capillary glass tube are close to but not in contact, so that the upper and lower parts of the capillary glass tube are aligned; 12 evenly distributed jet ports are opened on the inner side of the annular jet valve, and 12 branch pipes are arranged inside the ventilation pipe to connect the 12 jet ports respectively, and the branch pipes are connected to air pumps respectively, so that the jet is evenly sprayed from 360 degrees in all directions close to the capillary glass tube, effectively preventing the capillary glass tube from being skewed during the high-temperature hot melting process of hydrogen and oxygen flame.

[0016] Further preferably, considering that the gas ejected from the annular jet valve may affect the welding process of the oxyhydrogen flame below, a wind shield is installed around the jet port and the flame outlet of the oxyhydrogen flame high-temperature hot melting device, which can effectively isolate the air flow and reduce interference with the oxyhydrogen flame.

[0017] The spectrum monitoring system controls the five-dimensional translation stage to move the reflective optical fiber through the PID algorithm, thereby changing the cavity length of the FP cavity according to actual conditions to obtain the set target spectrum contrast.

[0018] The three nozzles of the oxyhydrogen flame high temperature hot melting device are evenly installed around the capillary glass tube, and are placed around the capillary glass tube at an interval of 120 degrees. The three oxyhydrogen flame nozzles heat simultaneously, making the welding more uniform and significantly improving the consistency and stability of the welding.

[0019] As in the prior patent application CN103644925A, the tube shaft base is fixed at the bottom of the device bracket, the tube shaft base is dynamically sealed with a vertical tube shaft, the reducer at the top of the tube shaft is connected to the capillary glass tube fixing fixture, the middle of the tube shaft passes through a three-jaw chuck, a fixed shaft and a fixed seat connected up and down, the upper part of the tube shaft is clamped by the three-jaw chuck and rotates with the three-jaw chuck, a tower-shaped joint is installed on the air hole of the tube shaft base connected to the tube shaft, and the tower-shaped joint is connected to the vacuum pump through an air pipe to realize the vacuum operation during the production process of the FP cavity sensor.

[0020] The method for manufacturing an optical fiber FP cavity sensor using the above-mentioned fully automatic manufacturing device comprises the following steps:

[0021] (1) With the aid of a capillary glass tube fixing fixture, the signal optical fiber and the capillary glass tube are integrated under the action of a hydrogen-oxygen flame high-temperature hot-melting device. During the welding process of the hydrogen-oxygen flame high-temperature hot-melting device, a straightening system is set on the periphery of the capillary glass tube, wherein a CCD microscope monitors and controls the jet volume of each jet port on the annular jet valve in real time through the control system controlling the adjustable power supply;

[0022] (2) Use a fiber optic cutter to cut off the sealed part at the top of the capillary glass tube. The reflective optical fiber is clamped and fixed by a five-dimensional translation stage and inserted from the top of the capillary glass tube. The spectrum of the optical fiber is monitored in real time using a spectrum monitoring system. After the ASE light source passes through a 1×N coupler, one optical fiber is used as a wavelength calibration channel. The other optical fibers are connected to the signal optical fiber interface of the capillary glass tube through a parallel 3DB directional coupler and a transmission optical fiber. The reflective spectrum modulated by the external measured parameter is returned along the original path as a sensing channel. After the wavelength calibration channel and the sensing channel undergo photoelectric conversion, amplification of weak photocurrent, and high-precision filtering and noise reduction processing, the wavelength calibration channel and the sensing channel are compared with high precision to perform analog-to-digital signal conversion. Finally, the spectrum image is displayed on the display of the control system, and the quality of the FP cavity is reflected by the spectrum contrast.

[0023] (3) Before the FP cavity is welded in the oxyhydrogen flame high-temperature hot-melt device, the capillary glass tube is fixed in place using a capillary glass tube fixture, and the PID algorithm is used to control the five-dimensional translation stage to move the reflective optical fiber to change the cavity length of the FP cavity to achieve the set target spectral contrast (10 dB);

[0024] (4) During welding, a timing device is used to set a small interval of the oxyhydrogen flame welding time, a moving device is used to set a distance interval from the oxyhydrogen flame to the quartz tube, and a fuel ratio device is used to adjust the fuel ratio of the oxyhydrogen flame to obtain the optimal time, distance, and fuel ratio parameters, thereby realizing automated welding.

[0025] The present invention designs a manufacturing device and method with glue-free packaging, controllable parameters and uniform welding. The device integrates a number of key technologies such as multi-nozzle hydrogen-oxygen high-temperature hot melting technology, precision vacuuming technology, flexible straightening technology and real-time monitoring technology of the manufacturing process, which not only greatly improves production efficiency and reduces production costs, but also significantly improves product precision and stability; through intelligent control methods, the consistency and stability of welding are significantly improved, the dependence on the operator's skill level is greatly reduced, and the operator's workload is effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings.

[0027] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0028] Figure 2 It is a schematic diagram of the main structure of the present invention;

[0029] Figure 3 It is a schematic diagram of the overall structure of the present invention;

[0030] Figure 4 It is a structural schematic diagram of the righting system of the present invention;

[0031] Figure 5 Schematic diagram of the control connection relationship of the righting system of the present invention;

[0032] Figure 6 It is a structural schematic diagram of the spectrum detection system of the present invention;

[0033] Figure 7 Schematic diagram of control connection relationship of the spectrum detection system of the present invention;

[0034] Figure 8 It is a schematic diagram of the installation position of the nozzle of the oxyhydrogen flame high temperature hot melting device of the present invention;

[0035] Fig. 9 It is a schematic diagram of the installation of the wind shield of the hydrogen-oxygen flame high-temperature hot melting device of the present invention.

[0036] In the figure, 1 is a capillary glass tube fixing fixture, 2 is a tube axis base, 3 is a vacuum pump, 4 is a capillary glass tube, 5 is a straightening system, 6 is a spectrum monitoring system, 7 is an oxyhydrogen flame high-temperature hot melting device, 8 is an annular jet valve, 9 is a ventilation duct, 10 is an air pump, 11 is a CCD microscope, 12 is a control system, 13 is an adjustable power supply, 14 is an ASE light source, 15 is a 1×N coupler, 16 is a wavelength calibration channel, 17 is a 3DB directional coupler, 18 is a signal optical fiber interface, 19 is an A / D converter, 20 is a display, 21 is a wind shield, and 22 is a five-dimensional translation stage. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0039] The present invention will be described in detail below with reference to the accompanying drawings.

[0040] Embodiment 1:

[0041] As attached Figure 1-Figure 6 As shown, a fully automatic manufacturing device for an optical fiber FP cavity sensor is proposed based on the prior patent application CN103644925A, which includes a device bracket, a capillary glass tube fixing fixture 1 is installed on the upper end of the device bracket, a collimating glass tube is fixed on the capillary glass tube fixing fixture 1, a capillary glass tube 4 passes through the collimating glass tube and is fixed on the capillary glass tube fixing fixture 1, a signal optical fiber and a reflection optical fiber are arranged in the capillary glass tube 4, a straightening system 5 is installed on the capillary glass tube 4, and a spectrum monitoring system 6 is connected to the signal optical fiber inside the capillary glass tube 4;

[0042] During the high-temperature melting process of hydrogen-oxygen flame, the capillary glass tube 4 at the molten part will melt and become soft, and it is easy to be skewed. In order to prevent this phenomenon, or to straighten the capillary glass tube 4 when it is skewed, a straightening system 5 is specially designed, which includes an annular jet valve 8 sleeved on the periphery of the capillary glass tube 4, and a CCD microscope 11 is fixed just above the annular jet valve 8. The signal of the CCD microscope 11 is connected to the control system 12, and the signal of the control system 12 is connected to the adjustable power supply 13 of the air pump 10. The air pump 10 is connected to the annular jet valve 8 through the ventilation pipe 9;

[0043] The spectrum monitoring system 6 includes an ASE light source 14 connected to a 1×N coupler 15, one optical fiber of the 1×N coupler 15 is used as a wavelength calibration channel 16 connected to an A / D converter 19, multiple optical fibers of the 1×N coupler 15 are connected in parallel to a plurality of 3DB directional couplers 17, the 3DB directional coupler 17 is connected to a signal optical fiber interface of a capillary glass tube 4 through a transmission optical fiber, and a reflection optical fiber of the capillary glass tube 4 is connected to the 3DB directional coupler 17, and a reflection signal of the 3DB directional coupler 17 passes through the A / D converter 19, and the A / D converter 19 is connected to a display 20 of the control system 12;

[0044] The reflecting optical fiber is clamped and fixed by a five-dimensional translation stage 22, and the hydrogen-oxygen flame high-temperature hot melting device 7 is installed around the capillary glass tube 4 through a moving device, and a timing device and a fuel proportioning device are arranged in the hydrogen-oxygen flame high-temperature hot melting device 7, and the five-dimensional translation stage 22, the moving device, the timing device and the fuel proportioning device are all connected to the spectral monitoring system 6.

[0045] The center of the annular jet valve 8 coincides with the center of the capillary glass tube 4, and the inner diameter of the annular jet valve 8 is slightly larger than the outer diameter of the capillary glass tube 4, so that the annular jet valve 8 is close to but not in contact with the capillary glass tube 4; 12 uniformly distributed jet ports are provided on the inner side of the annular jet valve 8, and 12 branch pipes are provided inside the ventilation pipe 9 to respectively connect the 12 jet ports, and the branch pipes are respectively connected to the air pump 10, so as to uniformly jet from 360 degrees in all directions close to the capillary glass tube.

[0046] Considering that the gas ejected from the annular jet valve may affect the welding process of the oxyhydrogen flame below, a wind shield 21 is installed around the jet port and the flame outlet of the oxyhydrogen flame high-temperature hot melting device 7, which can effectively isolate the interference of air flow on the oxyhydrogen flame.

[0047] The nozzles of the oxyhydrogen flame high temperature hot melting device 7 are three evenly installed around the capillary glass tube 4, and are placed around the capillary glass tube at an interval of 120 degrees. The three oxyhydrogen flame nozzles heat simultaneously to make the welding more uniform.

[0048] As described in the prior patent application CN103644925A, a tube shaft base 2 is fixed at the bottom of the device bracket, a vertical tube shaft is dynamically sealed on the tube shaft base 2, a reducer at the top of the tube shaft is connected to a capillary glass tube fixing fixture 1, a three-jaw chuck, a fixed shaft and a fixed seat connected up and down pass through the middle of the tube shaft, the upper part of the tube shaft is clamped by the three-jaw chuck and rotates with the three-jaw chuck, a tower-shaped joint is installed on the air hole of the tube shaft base 2 connected to the tube shaft, and the tower-shaped joint is connected to the vacuum pump 2 through an air pipe to realize the vacuum operation during the production process of the FP cavity sensor.

[0049] Embodiment 2:

[0050] A fully automatic manufacturing method of an optical fiber FP cavity sensor, which uses the fully automatic manufacturing device of the optical fiber FP cavity sensor described in Example 1, comprises the following steps:

[0051] (1) With the aid of the capillary glass tube fixing fixture 1, the signal optical fiber and the capillary glass tube 4 are integrated under the action of the hydrogen-oxygen flame high-temperature hot-melting device 7 (see the prior patent application CN103644925A for details, which will not be repeated here). During the welding process of the hydrogen-oxygen flame high-temperature hot-melting device 7, a straightening system 5 is set on the periphery of the capillary glass tube 4. When working, the center of the annular jet valve 8 is made to coincide with the center of the capillary glass tube 4. The annular jet valve 8 has 12 jet ports built in. The ventilation pipe 9 is divided into 12 branch pipes respectively connected to the above 12 jet ports, and the jet is evenly sprayed in all directions close to the capillary glass tube 4. If the capillary glass tube 4 is skewed due to uncontrollable reasons, the CCD microscope 11 will give real-time feedback signals to the control system 12. The control system 12 adjusts the air pump 10 connected to the corresponding jet port through the adjustable power supply 13 to increase the jet volume of the corresponding jet port to straighten the capillary glass tube 4. The control relationship is shown in the attached figure. Figure 5 As shown;

[0052] Considering that the gas ejected from the straightening system 5 may affect the welding process of the hydrogen-oxygen flame below, a dense wind shield 21 is installed around the jet outlet and the flame outlet of the hydrogen-oxygen flame high-temperature hot melting device 7 to effectively isolate the interference of air flow on the hydrogen-oxygen flame. Fig. 9 shown.

[0053] (2) Use a fiber optic cutter to cut off the sealed part at the top of the capillary glass tube 4. The reflective optical fiber is clamped and fixed by a five-dimensional translation stage 22 and inserted from the top of the capillary glass tube 4. The spectrum of the optical fiber is monitored in real time using a spectrum monitoring system 6. After the ASE light source 14 passes through the 1×N coupler 15, one optical fiber is used as a wavelength calibration channel 16. The other optical fibers are connected to the optical fiber interface of the capillary glass tube 4 through a parallel 3DB directional coupler 17 and a transmission optical fiber. The reflective spectrum modulated by the external measured parameter is returned along the original path as a sensing channel. After the wavelength calibration channel 16 and the sensing channel undergo photoelectric conversion, amplification of weak photocurrent, and high-precision filtering and noise reduction processing, the wavelength calibration channel 16 and the sensing channel are compared with high precision to perform analog-to-digital signal conversion. Finally, the spectrum image is displayed on the computer monitor 20 of the control system 12, and the quality of the FP cavity is reflected by the spectrum contrast.

[0054] In this embodiment, the spectral contrast ratio (SWP) of light waves is used to reflect the quality of the FP cavity (Fabry-Perot resonant cavity).

[0055] , where I max is the maximum light intensity of the spectrum, I minis the minimum intensity of the spectrum.

[0056] (3) Using a spectrum detection system 6 to monitor the spectrum of the optical fiber in real time, before the FP cavity is melted by the hydrogen-oxygen flame high-temperature hot-melting device 7, the capillary glass tube fixing fixture 1 is used to fix the position of the capillary glass tube 4, and the PID algorithm is used to control the five-dimensional translation stage 22 to move the reflective optical fiber to change the cavity length of the FP cavity to achieve the set target spectral contrast;

[0057] Since different sensors have different required parameters, their cavity lengths vary from 90μm to 300μm, which is not convenient to indicate through specific data. Therefore, the standard is set at spectral contrast ≥ 10dB.

[0058] (4) During welding, a timing device is used to set a small interval of the oxyhydrogen flame welding time, a moving device is used to set a distance interval from the oxyhydrogen flame to the quartz tube, and a fuel ratio device is used to adjust the fuel ratio of the oxyhydrogen flame to obtain the optimal time, distance, and fuel ratio parameters, thereby realizing automated welding.

[0059] Regarding the mutual influence of welding time, distance, fuel ratio, etc. on welding quality, the adjustment method of this device is:

[0060] a. First fix the appropriate fuel ratio and the distance between the flame and the optical fiber, only change the time, perform multiple welding, observe the change in welding quality, and enter the parameter changes of welding time and welding quality into the control system;

[0061] b. Fixed distance and time interval, only changed the fuel ratio, welded multiple times, observed the change in welding quality, and recorded the parameter changes of fuel ratio and welding quality into the control system;

[0062] c. Fix the time interval and fuel ratio, only change the distance, perform multiple welding, observe the change in welding quality, and enter the distance parameter and welding quality parameter changes into the control system.

[0063] In this embodiment, a high-precision mobile device is combined with a PID algorithm to control the distance between the oxyhydrogen flame and the quartz capillary, a timing device is used to set a series of small intervals of oxyhydrogen flame welding time, a series of distance intervals from the oxyhydrogen flame to the quartz tube, and the fuel ratio of the oxyhydrogen flame are set by the mobile device; the optical fiber FP cavity after processing is tested many times to obtain the best time, distance, fuel ratio and other parameters; finally, these key parameters are controlled to achieve automatic welding.

[0064] The present invention is an improvement on the original patent CN103644925A. Compared with the original patent, only one optical fiber FP cavity can be made at a time. The operation is completely controlled by manual control of the distance between the hydrogen-oxygen flame and the capillary glass tube, which leads to large errors and high requirements on the operator level (in addition to basic operations, the distance between the nozzle flame and the capillary glass tube is required to be manually controlled in real time during the welding process, and this operation requires long-term professional training and later long-term operation experience).

[0065] In contrast, the device of the present invention can simultaneously produce multiple optical fiber FP cavities at one time. Although the time consumption for a single production is the same or similar, the work efficiency is relatively improved. In addition, the device of the present invention adopts a PID algorithm and a high-precision distance control system, and obtains the optimal distance time, fuel ratio and other data through multiple experiments. Automatic control is achieved through these key data, so the operation accuracy is high; for the operator, only basic operations (placing the incident optical fiber, stripping off the coating layer of the signal optical fiber, cutting off the sealed part of the top of the capillary glass tube with a fiber optic cutting knife, and placing the reflected light on the five-dimensional displacement stage for clamping and fixing) are required. The above operations are simple and can be mastered quickly (within one day), so the requirements for the operator are relatively low.

[0066] There are significant differences in specific application parameters between the optical fiber FP cavity sensors made of different materials by the manufacturing method of this embodiment and the optical fiber FP cavity sensors made of quartz by the method disclosed in patent CN103644925A, as follows:

[0067]

[0068] From the above comparison, it can be seen that the optical fiber FP cavity sensor made of the same material obtained by the manufacturing method of this embodiment has a significantly higher yield rate and a shorter manufacturing cycle than the method disclosed in patent CN103644925A under the same flame and the same specifications.

[0069] In addition, in the technology disclosed in patent CN103644925A, only capillary quartz glass tubes are used to manufacture FP cavity sensors, and capillary glass tubes of other materials have never been considered. Therefore, other materials have not been compared for the time being. This proves that the manufacturing device of the present invention can appropriately adjust the combustion distance, combustion time, etc. for the processing of capillary glass tubes of different materials, thereby achieving a higher success rate in product manufacturing.

[0070] Embodiment 3:

[0071] A fully automatic method for making an optical fiber FP cavity sensor, the specific steps of which are as described in Example 2, it should be noted that as shown in the attached manual Figure 6This embodiment is equipped with a 1×N multi-spectral detection system. Each 3DB directional coupler controls a fiber FP cavity production unit (a FP cavity production unit is composed of a straightening system, an oxyhydrogen flame high-temperature hot melting device and a corresponding vacuum pumping device). The number of the production units corresponds to the number of 3DB directional couplers, and is uniformly managed by the multi-spectral detection system through a high-precision adjustment system and a computer (control system).

[0072] This embodiment can simultaneously manufacture multiple optical fiber FP cavities. Under the control of the multi-spectral detection system, the time taken by each manufacturing unit to manufacture one optical fiber FP cavity is basically the same as that of the original device. However, due to the multi-line operation, the working efficiency of the device is virtually improved. As described above, the manufacturing method of this embodiment is used to manufacture optical fiber FP cavity sensors of different materials. Multiple optical fiber FP cavities can be manufactured simultaneously in the same manufacturing cycle. The more the number, the shorter the average manufacturing cycle of a single optical fiber FP cavity.

[0073] It should be further pointed out that the fully automatic manufacturing device and manufacturing method of the present invention are also applicable to optical fiber FP cavity sensor manufacturing equipment other than the prior patent application CN103644925A. The straightening system 5, spectral monitoring system 6 and hydrogen-oxygen flame high-temperature hot melting device 7 of the present application can be applied to other optical fiber FP cavity sensor manufacturing equipment known in the art without affecting the overall structure of the original equipment.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A fully automatic manufacturing device for an optical fiber FP cavity sensor, comprising a device support, a capillary glass tube fixing fixture (1) is installed on the upper end of the device support, a collimating glass tube is fixed on the capillary glass tube fixing fixture (1), a capillary glass tube (4) passes through the collimating glass tube and is fixed on the capillary glass tube fixing fixture (1), and a signal optical fiber and a reflection optical fiber are arranged in the capillary glass tube (4), characterized in that: The capillary glass tube (4) is provided with a straightening system (5), and the signal optical fiber inside the capillary glass tube (4) is connected to a spectrum monitoring system (6); The straightening system (5) comprises an annular jet valve (8) sleeved on the periphery of the capillary glass tube (4), a CCD microscope (11) is fixed directly above the annular jet valve (8), the CCD microscope (11) is connected to the control system (12) by signal, the control system (12) is connected to the adjustable power supply (13) of the air pump (10), and the air pump (10) is connected to the annular jet valve (8) via a ventilation pipe (9); The spectrum monitoring system (6) comprises an ASE light source (14) connected to a 1×N coupler (15); one optical fiber of the 1×N coupler (15) is connected to an A / D converter (19) as a wavelength calibration channel (16); other multiple optical fibers of the 1×N coupler (15) are connected in parallel to a plurality of 3DB directional couplers (17); the 3DB directional coupler (17) is connected to a signal optical fiber interface (18) of a capillary glass tube (4) via a transmission optical fiber; and a reflection optical fiber of the capillary glass tube (4) is connected to the 3DB directional coupler (17); a reflection signal of the 3DB directional coupler (17) passes through an A / D converter (19); and the A / D converter (19) is connected to a display (20) of a control system (12); The reflective optical fiber is clamped and fixed by a five-dimensional displacement stage (22); the hydrogen-oxygen flame high-temperature hot-melting device (7) is installed around the capillary glass tube (4) via a moving device; a timing device and a fuel proportioning device are arranged in the hydrogen-oxygen flame high-temperature hot-melting device (7); and the five-dimensional displacement stage (22), the moving device, the timing device and the fuel proportioning device are all connected to the spectrum monitoring system (6).

2. The fully automatic manufacturing device for optical fiber FP cavity sensor according to claim 1, characterized in that: The center of the annular jet valve (8) coincides with the center of the capillary glass tube (4), and the inner diameter of the annular jet valve (8) is slightly larger than the outer diameter of the capillary glass tube (4); 12 evenly distributed jet ports are provided on the inner side of the annular jet valve (8), and 12 branch pipes are provided inside the ventilation pipe (9) and are respectively connected to the 12 jet ports, and the branch pipes are respectively connected to the air pump (10).

3. The fully automatic manufacturing device for optical fiber FP cavity sensor according to claim 1, characterized in that: A wind shield (21) is installed around the air jet outlet and the flame outlet of the oxyhydrogen flame high-temperature hot melting device (7).

4. The fully automatic manufacturing device for optical fiber FP cavity sensor according to claim 1, characterized in that: The spectrum monitoring system (6) controls the five-dimensional displacement stage (22) to move the reflective optical fiber through a PID algorithm.

5. The fully automatic manufacturing device for optical fiber FP cavity sensor according to claim 1, characterized in that: The oxyhydrogen flame high-temperature hot melting device (7) comprises three nozzles which are evenly distributed and installed around the capillary glass tube (4).

6. The fully automatic manufacturing device for optical fiber FP cavity sensor according to claim 1, characterized in that: The bottom of the device support is fixed with a tube shaft base (2), a vertical tube shaft is dynamically sealed on the tube shaft base (2), a reducer on the top of the tube shaft is connected to a capillary glass tube fixing fixture (1), the middle of the tube shaft passes through a three-jaw chuck, a fixed shaft and a fixed seat connected up and down, the upper part of the tube shaft is clamped by the three-jaw chuck and rotates with the three-jaw chuck, and a tower-shaped joint is installed on the air hole of the tube shaft base (2) connected to the tube shaft, and the tower-shaped joint is connected to a vacuum pump (3) through an air pipe.

7. A method for manufacturing an optical fiber FP cavity sensor using the fully automatic manufacturing device for the optical fiber FP cavity sensor according to claim 1, characterized in that it comprises the following steps: (1) With the aid of a capillary glass tube fixing fixture (1), the signal optical fiber and the capillary glass tube (4) are integrated under the action of a hydrogen-oxygen flame high-temperature hot-melting device (7). During the welding process of the hydrogen-oxygen flame high-temperature hot-melting device (7), a straightening system (5) is set on the periphery of the capillary glass tube (4), wherein a CCD microscope (11) monitors and controls the jet volume of each jet port on the annular jet valve (8) in real time through the control system (12) controlling the adjustable power supply (13); (2) Cut off the sealed portion of the top of the capillary glass tube (4) with a fiber optic cutter, fix the reflective optical fiber by a five-dimensional displacement stage (22), and insert it from the top of the capillary glass tube (4). Use the spectrum monitoring system (6) to monitor the spectrum of the optical fiber in real time. After the ASE light source (14) passes through the 1×N coupler (15), one optical fiber is used as a wavelength calibration channel (16), and the other optical fibers are connected to the signal optical fiber interface (18) of the capillary glass tube (4) through a parallel 3DB directional coupler (17) and a transmission optical fiber. The reflective spectrum modulated by the external measured parameter is returned along the original path as a sensing channel. After the wavelength calibration channel (16) and the sensing channel undergo photoelectric conversion, amplification of weak photocurrent, and high-precision filtering and noise reduction processing, the wavelength calibration channel (16) and the sensing channel are compared with high precision to perform analog-to-digital signal conversion. Finally, the spectrum image is displayed on the display (20) of the control system (12), and the quality of the FP cavity is reflected by the spectrum contrast. (3) Before the FP cavity is welded by the oxyhydrogen flame high temperature hot melting device (7), the capillary glass tube fixing fixture (1) is used to fix the position of the capillary glass tube (4), and the PID algorithm is used to control the five-dimensional translation stage (22) to move the reflecting optical fiber to change the cavity length of the FP cavity to achieve the set target spectral contrast; (4) During welding, a timing device is used to set a small interval of the oxyhydrogen flame welding time, a moving device is used to set a distance interval from the oxyhydrogen flame to the quartz tube, and a fuel ratio device is used to adjust the fuel ratio of the oxyhydrogen flame to obtain the optimal time, distance, and fuel ratio parameters, thereby realizing automated welding.

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