Single crystal optical fiber packaging device and single crystal optical fiber sensing probe

Abstract

The present application discloses a single crystal optical fiber packaging device and a single crystal optical fiber sensing probe. The single crystal optical fiber packaging device includes a protective sleeve for accommodating the single crystal optical fiber, a stop valve and an inflation device. The material of the protective sleeve will not react chemically with the material of the single crystal optical fiber. The inflation device is connected to the protective sleeve through the stop valve, and the protective sleeve is evacuated or a protective gas is filled into the protective sleeve. Therefore, inflation can be achieved using the single crystal optical fiber packaging device of the present application, which increases the reusability of the device to a certain extent. The type and pressure of the gas filled into the device can be flexibly selected according to experimental requirements, and it is also beneficial to maintain a constant air pressure in the protective sleeve; furthermore, after the single crystal optical fiber is packaged using the protective sleeve as the packaging body, the single crystal optical fiber is located in a closed environment, which prevents the single crystal optical fiber from being contaminated by the complex and harsh external environment, and can also avoid chemical reactions that may occur in the single crystal optical fiber, thereby improving the stability of the optical fiber.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a single crystal optical fiber packaging device and a single crystal optical fiber sensing probe. Background Art

[0002] Aircraft engines need to work in extremely harsh environments such as high temperature and high pressure. Among them, aircraft engine status perception and intelligent diagnosis are one of the key issues to ensure the long-term safe operation of aircraft engines. Among the many information perceptions of aircraft engines, high temperature monitoring is an important part. Thermocouples, crystal temperature measurement technology, radiation temperature measurement method, etc. are all used in high temperature monitoring of aircraft engines. Optical fiber temperature measurement has natural advantages such as anti-electromagnetic interference, light weight, and small size, and has gradually begun to be used in the structural safety monitoring of aerospace systems. However, traditional quartz optical fibers are generally only suitable for temperatures below 300°C, and have inherent limitations in ultra-high temperature environments such as aircraft engines. Generally, a coating is applied on the surface of the optical fiber to protect the optical fiber, but its long-term stability at high temperatures is currently difficult to guarantee.

[0003] In order to improve the high temperature adaptability of optical fiber sensor probes, sensor probes based on single crystal fiber have been continuously developed in recent years. Taking single crystal sapphire fiber as an example, the following is an explanation:

[0004] The melting point of single-crystal sapphire optical fiber is as high as 2054℃ and it has good optical transmission characteristics in the visible to near-infrared band. Compared with traditional quartz optical fiber, it has a higher melting point and laser damage threshold, higher corrosion resistance, mechanical properties and a wider spectral transmission range. It is one of the best material choices for the development of sensor probes in high-temperature environments. Therefore, the development of single-crystal optical fiber sensor probes (such as single-crystal sapphire optical fiber sensor probes) has great research significance and practical value for monitoring harsh environments such as aircraft engines.

[0005] Since single-crystal sapphire optical fiber will react chemically with components in the outside air at high temperatures, after long-term operation (>100 hours) in an ultra-high temperature environment of 1500°C, aluminum hydroxide will be generated on the surface of the single-crystal sapphire optical fiber, resulting in surface degradation phenomena such as loss spots and micro-etching lines, causing the surface of the single-crystal sapphire optical fiber to be uneven, thereby destroying the total internal reflection constraint conditions of light transmission and greatly affecting the transmission efficiency of the single-crystal sapphire optical fiber to the signal light. Therefore, in order to ensure the reliability of the long-term operation of the single-crystal optical fiber sensor probe in an ultra-high temperature environment, the single-crystal sapphire optical fiber can be packaged.

[0006] At present, an optical fiber packaging device includes a protective sleeve (also called a sapphire tube) and seals (seal devices) plugged at both ends of the protective sleeve. The optical fiber packaging device is a one-time package for the optical fiber (gas can only be filled once), which is not conducive to maintaining a constant gas pressure in the protective sleeve. Summary of the invention

[0007] The purpose of the present application is to disclose a single crystal optical fiber packaging device and a single crystal optical fiber sensing probe. The single crystal optical fiber packaging device or the single crystal optical fiber sensing probe can be inflated multiple times, which not only improves the reusability, but also allows the type and pressure of the inflated gas to be flexibly selected according to the experimental requirements, and is also conducive to maintaining a constant air pressure in the protective sleeve.

[0008] In a first aspect, the present application discloses a single crystal optical fiber packaging device. The single crystal optical fiber packaging device comprises a protective sleeve for accommodating the single crystal optical fiber, a stop valve, and an inflation device. The protective sleeve is dense and airtight, the material of the protective sleeve will not chemically react with the material of the single crystal optical fiber, and the melting point of the protective sleeve is not lower than the melting point of the single crystal optical fiber. The inflation device is connected to the protective sleeve through the stop valve, and when the stop valve is opened, the protective sleeve is evacuated or a protective gas is filled into the protective sleeve.

[0009] In some embodiments, the single crystal optical fiber packaging device includes a first three-way joint and a connector, wherein the first end of the first three-way joint is connected to the stop valve, and the second end of the first three-way joint is connected to the first end of the protective sleeve; one of the third end of the first three-way joint and the second end of the protective sleeve is sealed, and the other is sealedly connected to the connector, and the connector is used to connect to the single crystal optical fiber passing through the protective sleeve.

[0010] In some embodiments, the single crystal optical fiber packaging device includes a first three-way joint, a first connector, and a second connector, wherein the first end of the first three-way joint is connected to the stop valve; the second end of the first three-way joint is connected to the protective sleeve, the third end of the first three-way joint is sealedly connected to the first connector, and the second end of the protective sleeve is sealedly connected to the second connector, so that both ends of the single crystal optical fiber pass through the protective sleeve and are correspondingly connected to the first connector and the second connector.

[0011] In some embodiments, the inflation device includes a second three-way joint, a vacuum pump, an air supply device and a valve, wherein: one of the vacuum pump and the air supply device is connected to the first end of the second three-way joint through a valve, and the other of the vacuum pump and the air supply device is connected to the second end of the second three-way joint; the third end of the second three-way joint is connected to the stop valve.

[0012] In some embodiments, the protective sleeve includes a heated section; the single crystal optical fiber packaging device includes two capillaries, the two capillaries are respectively inserted into the protective sleeve from opposite ends of the protective sleeve and are separated from the heated section.

[0013] In some embodiments, the length of each capillary extending into the protective sleeve from the end of the protective sleeve is D, 0 cm < D ≤ 20 cm.

[0014] In some embodiments, the single crystal optical fiber packaging device includes a pressure monitor connected to a passage between the shut-off valve and the protective sleeve.

[0015] In some embodiments, the single crystal optical fiber packaging device includes a low temperature section, and the single crystal optical fiber packaging device includes an air chamber, and the air chamber is connected to the heated section of the protective sleeve through the low temperature section.

[0016] In some embodiments, when the single crystal optical fiber is a sapphire optical fiber, a single crystal sapphire fiber grating, a single crystal sapphire fiber Fabry-Perot cavity, or a single crystal optical fiber containing femtosecond laser micromachining, the protective sleeve is a sapphire tube, or a high-purity alumina ceramic tube; when the single crystal optical fiber is a YAG (yttrium aluminum garnet crystal) optical fiber, a YAG-doped optical fiber, a single crystal YAG fiber grating, a single crystal YAG fiber Fabry-Perot cavity, or a single crystal optical fiber containing femtosecond laser micromachining, the protective sleeve is a YAG single crystal tube.

[0017] In a second aspect, the present application discloses a single crystal optical fiber sensing probe. The single crystal optical fiber sensing probe comprises a single crystal optical fiber, a protective sleeve and a stop valve, wherein the single crystal optical fiber is passed through the protective sleeve, the protective sleeve is dense and airtight, the material of the protective sleeve will not chemically react with the material of the single crystal optical fiber, and the melting point of the protective sleeve is not lower than the melting point of the single crystal optical fiber; the stop valve is connected to the protective sleeve to open and close the protective sleeve.

[0018] In some embodiments, the single crystal optical fiber sensing probe includes a first three-way joint and a connector, wherein the first end of the first three-way joint is connected to the stop valve, and the second end of the first three-way joint is connected to the first end of the protective sleeve; one of the third end of the first three-way joint and the second end of the protective sleeve is sealed, and the other is sealedly connected to the connector, and the connector is used to connect to the single crystal optical fiber passing through the protective sleeve.

[0019] In some embodiments, the single crystal optical fiber sensing probe includes a first three-way joint, a first connector, and a second connector, wherein the first end of the first three-way joint is connected to the stop valve; the second end of the first three-way joint is connected to the protective sleeve, the third end of the first three-way joint is sealedly connected to the first connector, and the second end of the protective sleeve is sealedly connected to the second connector, so that both ends of the single crystal optical fiber pass through the protective sleeve and are correspondingly connected to the first connector and the second connector.

[0020] In some embodiments, the protective sleeve includes a heated section; the single crystal optical fiber sensing probe includes two capillaries, the two capillaries are respectively inserted into the protective sleeve from opposite ends of the protective sleeve and are separated from the heated section.

[0021] In some embodiments, the length of each capillary extending into the protective sleeve from the end of the protective sleeve is D, 0 cm < D ≤ 20 cm.

[0022] In some embodiments, the single crystal optical fiber sensing probe includes a pressure monitor connected to a passage between the shut-off valve and the protective sleeve.

[0023] In some embodiments, the single crystal optical fiber sensing probe includes a low temperature section, the single crystal optical fiber sensing probe includes an air chamber, and the air chamber is connected to the heated section of the protective sleeve through the low temperature section.

[0024] In some embodiments, when the single crystal optical fiber is a sapphire optical fiber, a single crystal sapphire fiber grating, a single crystal sapphire fiber Fabry-Perot cavity, or a single crystal optical fiber containing femtosecond laser microprocessing, the protective sleeve is a sapphire tube, or a high-purity alumina ceramic tube; or, when the single crystal optical fiber is a YAG optical fiber, a YAG-doped optical fiber, a single crystal YAG fiber grating, a single crystal YAG fiber Fabry-Perot cavity, or a single crystal optical fiber containing femtosecond laser microprocessing, the protective sleeve is a YAG single crystal tube.

[0025] For the single crystal optical fiber packaging device or the single crystal optical fiber sensing probe, when it is necessary to inflate the protective sleeve, the stop valve is opened, and the protective gas is inflated into the protective sleeve through the inflation device. When it is not necessary to inflate, the stop valve is closed, and the inflation device stops inflating. In this way, the reusability of the single crystal optical fiber packaging device or the single crystal optical fiber sensing probe is increased to a certain extent; the type and pressure of the gas inflated into the protective sleeve can be flexibly selected according to experimental requirements, which is conducive to maintaining the constant air pressure in the protective sleeve; furthermore, after the single crystal optical fiber is encapsulated using the protective sleeve as the packaging body, because the protective sleeve is dense and airtight, the single crystal optical fiber is located in a closed environment, thereby preventing the single crystal optical fiber from being contaminated by the complex and harsh external environment; finally, the protective sleeve is filled with protective gas, the material of the protective sleeve and the material of the single crystal optical fiber will not react chemically, and the melting point of the protective sleeve is not lower than the melting point of the single crystal optical fiber. Therefore, the protection of the protective sleeve combined with the protection of the protective gas can prevent the chemical reaction that may occur in the single crystal optical fiber under high temperature environment, thereby improving the stability of the single crystal optical fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic diagram of a first single crystal optical fiber packaging device according to an embodiment of the present application;

[0027] Figure 2 yes Figure 1 A magnified view of part A;

[0028] Figure 3 is a schematic diagram of a second single crystal optical fiber packaging device according to an embodiment of the present application;

[0029] Figure 4 is a schematic diagram of a third single crystal optical fiber packaging device according to an embodiment of the present application;

[0030] Figure 5 is a schematic diagram of a fourth single crystal optical fiber packaging device according to an embodiment of the present application;

[0031] Figure 6 is a schematic diagram of a fifth single crystal optical fiber packaging device according to an embodiment of the present application;

[0032] Figure 7 is a schematic diagram of a sixth single crystal optical fiber packaging device according to an embodiment of the present application. DETAILED DESCRIPTION

[0033] Here, the technical solutions in the embodiments (or "implementation methods") of the present application will be described clearly and completely in conjunction with the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0034] If there are terms involving directional indications or positional relationships in the embodiments of the present application (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings); if the specific posture changes, the directional indication or positional relationship will also change accordingly. In addition, the terms "first" and "second" in the embodiments of the present application are only used for the purpose of convenience of description and cannot be understood as indicating or implying relative importance.

[0035] Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 A total of six single crystal optical fiber packaging devices are disclosed. These six single crystal optical fiber packaging devices all include a protective sleeve 2, a stop valve 3 and an air filling device 4 for accommodating a single crystal optical fiber 1. Of course, the connection between the protective sleeve 2, the stop valve 3 and the air filling device 4 is not limited to the connection method described in this application. The protective sleeve 2 is dense and airtight, and the material of the protective sleeve 2 will not chemically react with the material of the single crystal optical fiber 1, and the melting point of the protective sleeve 2 is not lower than the melting point of the single crystal optical fiber 1. The air filling device 4 is connected to the protective sleeve 2 through the stop valve 3. When the stop valve 3 is opened, the protective sleeve 2 is evacuated or a protective gas is filled into the protective sleeve 2. That is, when it is necessary to evacuate the interior of the protective sleeve 2, the stop valve 3 is opened and the protective sleeve 2 is evacuated. When it is necessary to fill the protective sleeve 2 with a protective gas, the stop valve 3 is in an open state, and the protective sleeve 2 is filled with a protective gas. The protective gas is usually an inert gas, which is extremely inactive in chemical properties and generally not easy to combine with other elements. For example, helium, neon, argon, krypton, xenon, radon, etc., can achieve the following effects. The protective gas can be filled into the inflation device 4 during the packaging process, or during the operation of the single crystal optical fiber sensor probe (also known as online inflation), depending on the specific situation. During inflation, the protective gas filled can be a single protective gas or a mixed gas composed of several protective gases.

[0036] In addition, the technicians can understand that the various connections of the single crystal optical fiber packaging device in the above-mentioned various embodiments are sealed (that is, the connection of this application includes the meaning of sealing when the corresponding connection requires a sealed connection). According to the specific conditions such as the connection method of the connection, the corresponding sealing method is adopted. For example, in the subsequent embodiments, the connection between the stop valve 3 and the first three-way joint 51 is sealed by a metal tube 591 (thin-walled tube) or a thin tube; for another example, the corresponding connections of the metal fitting 592, the metal tube 591, the protective sleeve 2 and the capillary 8 are fixed and sealed using high-temperature sealant.

[0037] As set up above, when it is necessary to inflate the protective sleeve 2, the stop valve 3 is opened, and the protective gas is inflated into the protective sleeve 2 through the inflation device 4. When it is not necessary to inflate the protective sleeve 2, the stop valve 3 is closed, and the inflation device 4 stops inflating. In this way, the reusability of the single crystal optical fiber packaging device is increased to a certain extent, and the type and pressure of the gas filled into the protective sleeve 2 can be flexibly selected according to the experimental requirements, which is conducive to maintaining the constant air pressure in the protective sleeve 2; furthermore, the protective sleeve 2 is used as the packaging body for the single crystal optical fiber. After the fiber is encapsulated, because the protective sleeve 2 is dense and airtight, the single crystal optical fiber 1 is located in a closed environment, thereby preventing the single crystal optical fiber 1 from being contaminated by the complex and harsh external environment; finally, the protective sleeve 2 is filled with a protective gas, the material of the protective sleeve 2 and the material of the single crystal optical fiber 1 will not chemically react, and the melting point of the protective sleeve 2 is not lower than the melting point of the single crystal optical fiber 1. Therefore, the protection of the protective sleeve 2 combined with the protection of the protective gas can prevent the chemical reactions that may occur in the single crystal optical fiber 1 in a high temperature environment, thereby improving the stability of the single crystal optical fiber.

[0038] See also Figure 6 and will Figure 6 and Figure 1 , Figure 3 , Figure 4 and Figure 5In comparison, the single crystal optical fiber packaging device includes a first three-way joint 51 and a connector (for the convenience of distinguishing from the subsequent embodiments, this connector is referred to as the first connector 52). The first connector 52 is not limited, for example, an optical fiber FC connector. The first end of the first three-way joint 51 is connected to the stop valve 3, and the connection method is not limited, for example, it is connected through a metal tube 591. The metal tube 591 is not limited, as long as it can meet the sealing requirements, such as a brass tube. The second end of the first three-way joint 51 is connected to the first end of the protective sleeve 2, and the connection method is not limited, for example, the second end is connected to the first end of the protective sleeve 2 through a metal fitting 592. The third end of the first three-way joint 51 is sealed and connected to the first connector 52. The first connector 52 is used to connect the single crystal optical fiber passing through the first end of the protective sleeve 2, the third end of the first three-way joint 51, and the first optical fiber protection structure 6. The structure of the first optical fiber protection structure 6 is not limited. How to seal the connection is not limited, for example, it is sealed and connected through the first optical fiber protection structure 6. For example, the first optical fiber protection structure 6 includes a metal tube 591 and a metal fitting 592. The third end of the first three-way joint 51 is connected to the first connector 52 through a metal tube 591 and a metal fitting 592. The first connector 52 can be connected to a temperature measurement system. The second end of the protective sleeve 2 is sealed.

[0039] As described above, one end of the single crystal optical fiber 1 passes through the first end of the protective sleeve 2 and is connected to the first connector 52 (that is, one end of the single crystal optical fiber 1 is exposed from the protective sleeve 2), and the second end of the protective sleeve 2 is sealed. In this way, useful data can be obtained through the first connector 52. For example, when the first connector 52 is connected to the temperature measurement system, accurate temperature monitoring of the single crystal optical fiber and its contact area during the packaging process can be achieved, which is convenient for timely adjustment of heating operations during the packaging process to ensure packaging quality. In addition, through the protection of the first optical fiber protection structure 6, the optical fiber is not easily damaged or contaminated by the external environment, etc.

[0040] See also Figure 7 , Figure 6 is the second end of the sealing protection sleeve 2, Figure 7 and Figure 6 compared to, Figure 7 It is the third end of the sealed first three-way joint 51. As follows, in conjunction with the accompanying drawings, a more detailed description is given:

[0041] See also Figure 7 , and Figure 7 and Figure 1 , Figure 3 , Figure 4 and Figure 5In comparison, the single crystal optical fiber packaging device includes a first three-way connector 51 and a connector (referred to as a second connector 53 to distinguish it from the aforementioned connector). The structure of the second connector 53 is not limited. For example, in the present application, the second connector 53 includes a component consisting of a bare fiber adapter 593 and a flange coupler 7. In other embodiments, the second connector 53 may also be just a bare fiber adapter 593, or a flange coupler 7. The first end of the first three-way connector 51 is connected to the stop valve. The second end of the first three-way connector 51 is connected to the first end of the protective sleeve 2. The third end of the first three-way connector 51 is sealed. There is no limit to how to seal, for example, by sealing with a sealant, or, at this time, the first three-way connector 51 is actually a two-way connector. The second connector 53 is sealed and connected to the second end of the protective sleeve 2. There is no limit to how to seal and connect, for example, by sealing and connecting through a second optical fiber protection structure. The structure of the second optical fiber protection structure is not limited. For example, the second optical fiber protection structure includes a metal tube 591 and a metal fitting 592. The metal tube 591 is connected to the second end of the protective sleeve 2, and the two ends of the metal fitting 592 are respectively connected to the metal tube 591 and the bare fiber adapter 593. The bare fiber adapter 593 is connected to the flange coupler 7. By providing the second connector 53, the single crystal optical fiber 1 can be connected to external equipment such as a spectrometer.

[0042] As described above, by sealing the third end of the first three-way connector 51 and setting the second connector 53, after connecting the second connector 53 to an external device such as a spectrometer, the optical signal of the single crystal optical fiber 1 can be measured (which can also be considered as a kind of useful data) to evaluate the performance of the single crystal optical fiber 1 after packaging, for example, by analyzing the spectral characteristics of the wavelength distribution and intensity distribution of the optical signal in the optical fiber; for example, during the packaging process, the optical performance of the single crystal optical fiber may be affected by heat treatment, strain or other factors. By connecting to the spectrometer for testing in real time or regularly, these changes can be monitored to ensure that the optical fiber performance meets the expected standards, such as maintaining low loss, high bandwidth or specific spectral transmittance characteristics.

[0043] Figure 5 and Figure 6 In the embodiment shown, one end of the single crystal fiber packaging device is sealed, and the single crystal fiber extends from the other end to be connected to the connector. Based on this, both ends of the single crystal fiber can also pass through the protective sleeve 2, as follows, a more detailed description:

[0044] See also Figure 1 , Figure 3 , Figure 4 and Figure 5The single crystal optical fiber packaging device includes a first three-way joint 51, a first connector 52 and a second connector 53. The first end of the first three-way joint 51 is connected to the stop valve 3; the second end of the first three-way joint 51 is connected to the protective sleeve 2, the third end of the first three-way joint 51 is sealedly connected to the first connector 52, and the second end of the protective sleeve 2 is sealedly connected to the second connector 53, so that both ends of the single crystal optical fiber 1 pass through the protective sleeve 2 and are correspondingly connected to the first connector 52 and the second connector 53.

[0045] As configured above, both ends of the single crystal optical fiber 1 of the single crystal optical fiber packaging device pass through the protective sleeve and are connected to external devices through the first connector 52 and the second connector 53 respectively, which is more conducive to obtaining useful data.

[0046] In the embodiment of the present application, the inflatable device 4 may be an integrated device, and one device can realize the functions of pumping and inflating. However, in other embodiments, the inflatable device 4 may also be composed of two devices, and this embodiment is described as follows:

[0047] See also Figure 3 , Figure 4 and Figure 5 The inflation device includes a second three-way connector 41, a vacuum pump 42, an air supply device 43 and a valve 44. The structure of the air supply device 43 is not limited. Figure 3 , Figure 4 and Figure 5 In the embodiment, the gas supply device 43 includes a one-way valve, a flow meter and a pressure reducing valve. The valve 44 is a stop valve in this embodiment. Figures 3 to 5 In the embodiment, the vacuum pump 42 is connected to the first end of the second three-way joint 41 through the valve 44. The air supply device 43 is connected to the second end of the second three-way joint 41. In other embodiments, the air supply device 43 may be connected to the second three-way joint 41 through the valve 44, and the vacuum pump 42 is directly connected to the second three-way joint 41. In short, no matter how the valve 44 is connected, as long as one way is supplied with air, the other way can be closed. The third end of the second three-way joint 41 is connected to the stop valve 3.

[0048] As configured above, the inflation device 4 includes a second three-way connector 41, a vacuum pump 42, a gas supply device 43 and a valve 44, and based on the connection relationship, it is not only convenient to inflate, but also can ensure the packaging quality. For example, a) after vacuuming by the vacuum pump 42, inflation can be carried out, which can effectively remove these harmful substances and protect the single crystal optical fiber 1 from oxidation and moisture damage, thereby extending the service life of the single crystal optical fiber 1; b) after vacuuming, filling with protective gas (such as argon) can prevent the risk of particulate contamination; c) after vacuuming, filling with protective gas and packaging can ensure the cleanliness of the protective sleeve 2, reduce light scattering, and maintain high-fidelity transmission of the signal.

[0049] See also Figure 2 Combined with Figure 1 , Figure 3 , Figure 4 and Figure 5 , the protective sleeve 2 includes a heated section 21. In an embodiment of the present application, the heated section 21 is heated by a high temperature furnace 20. The single crystal optical fiber packaging device includes two capillaries 8, which are inserted into the protective sleeve 2 from opposite ends of the protective sleeve 2 and are separated from the heated section. The separation distance is Figure 2 The material of the capillary is not limited, for example, it can be metal, and the metal material is not limited to stainless steel.

[0050] As described above, by providing the capillary 8, the capillary 8 can protect the single crystal optical fiber 1. At the same time, the capillary 8 is separated from the heated section 21. During the packaging process, it can be ensured that the performance of the capillary 8 will not be affected by heat.

[0051] See also Figure 2, the length of each capillary 8 extending into the protective sleeve 2 from the end of the protective sleeve 2 is D, 0cm<D≤20cm. For example, 0.5cm, 0.8cm, 1cm, 1.3cm, 1.5cm, 1.8cm, 2cm, 2.3cm, 2.5cm, 2.8cm, 3cm, 3.2cm, 3.4cm, 3.6cm, 3.8cm, 4cm, 4.3cm, 4.5cm, 4.8cm, 5cm, 5.5cm, 5.8cm, 6cm, 6.5cm, 7cm, 7.3cm, 7.5cm, 7.7cm, 8cm, 8.3cm, 8.5cm, 8.7cm, 9cm, 9.2cm, 9.5cm, 9.8 18cm, 18.2cm, 18.5cm, 18.8cm, 19cm, 19.3cm, 19.5cm, 19.8cm or 20cm.

[0052] As set above, since 0cm<D≤20cm, on the one hand, the capillary 8 can protect the single crystal optical fiber 1, and on the other hand, the capillary 8 is far away from the heating section 11, which can prevent the heat from affecting the performance of the capillary 8.

[0053] See also Figure 4 and Figure 5 The single crystal optical fiber packaging device includes a pressure monitor 91, and the pressure monitor 91 is connected to the passage between the stop valve 3 and the protection sleeve 2. In this embodiment, the pressure monitor 91 is connected to the passage between the stop valve 3 and the first three-way connector 51.

[0054] As described above, by setting the pressure monitor 91, the internal gas pressure (also considered as a kind of useful data) can be monitored in real time by the pressure monitor 91, and a gas leakage alarm can be given.

[0055] See also Figure 5 , the single crystal optical fiber packaging device includes a low temperature section. The low temperature section is relative to the heated section 21. The single crystal optical fiber packaging device includes an air chamber 92. The structure of the air chamber 92 is not limited. For example, the air chamber 92 is a section of connecting pipe. In some embodiments, a pressure gauge can also be connected to the connecting pipe. The air chamber 92 is connected to the heated section 21 of the protective sleeve 2 through the low temperature section. Although Figure 5The illustrated embodiment includes a pressure monitor 91 , and a skilled person may understand that in other embodiments, the pressure monitor 91 may not be included, and only the air chamber 92 may be provided.

[0056] As described above, by providing the air chamber 92, the air chamber 92 is connected to the heated section 21, so that the air chamber 92 can provide a buffer space for the expanding gas at high temperature, reduce the internal pressure, and reduce the possibility of gas leakage.

[0057] In some embodiments, when the single crystal optical fiber 1 is a sapphire optical fiber (which can be considered as a bare fiber), a single crystal sapphire fiber grating, a single crystal sapphire fiber Fabry-Perot cavity, or a single crystal optical fiber containing femtosecond laser micromachining, the protective sleeve 2 is a sapphire tube, or a high-purity alumina ceramic tube; when the single crystal optical fiber 1 is a YAG optical fiber, a YAG-doped optical fiber, a single crystal YAG fiber grating, a single crystal YAG fiber Fabry-Perot cavity, or a single crystal optical fiber containing femtosecond laser micromachining, the protective sleeve 2 is a YAG single crystal tube.

[0058] As set up as above, based on the relationship between the material of the protective sleeve 2 and the material of the single crystal optical fiber 1, it is possible to further effectively avoid chemical reactions and contamination caused by contact between other materials and the single crystal optical fiber 1, and maintain strength at high temperatures, thereby achieving a good packaging effect.

[0059] In the second aspect, the embodiments of the present application disclose a single crystal optical fiber sensing probe. The description of some structures and / or beneficial effects of the single crystal optical fiber sensing probe can refer to the description of the structure and / or beneficial effects of the single crystal optical fiber packaging device. The single crystal optical fiber sensing probe includes a single crystal optical fiber 1, a protective sleeve 2 and a stop valve 3, wherein the single crystal optical fiber 1 is passed through the protective sleeve 2, the protective sleeve 2 is dense and airtight, the material of the protective sleeve 2 will not chemically react with the material of the single crystal optical fiber 1, and the melting point of the protective sleeve is not lower than the melting point of the single crystal optical fiber; the stop valve 3 is connected to the protective sleeve 2 to switch the protective sleeve. When the stop valve 3 is in the open state, the protective sleeve 2 can be evacuated or filled with protective gas.

[0060] As set up as above, for the single-crystal optical fiber sensing probe, when it is necessary to inflate the protective sleeve, after connecting the inflation device to the stop valve, the stop valve is opened, and the protective gas is inflated into the protective sleeve through the inflation device. When inflation is not needed, the stop valve is closed and the inflation device stops inflating. In this way, the reusability of the single-crystal optical fiber sensing probe is increased to a certain extent; the type and pressure of the gas filled into the protective sleeve can be flexibly selected according to experimental requirements, which is conducive to maintaining the constant air pressure in the protective sleeve; furthermore, because the protective sleeve is dense and airtight, the single-crystal optical fiber is located in a closed environment, which prevents the single-crystal optical fiber from being contaminated by the complex and harsh external environment; finally, the protective sleeve is filled with protective gas, the material of the protective sleeve and the material of the single-crystal optical fiber will not react chemically, and the melting point of the protective sleeve is not lower than the melting point of the single-crystal optical fiber. Therefore, the protection of the protective sleeve combined with the protection of the protective gas can prevent the chemical reaction that may occur in the single-crystal optical fiber in a high-temperature environment, thereby improving the stability of the single-crystal optical fiber.

[0061] In some embodiments, see Figure 7 and Figure 6 The single crystal optical fiber sensing probe includes a first three-way joint and a connector, wherein the first end of the first three-way joint is connected to the stop valve, and the second end of the first three-way joint is connected to the first end of the protective sleeve; one of the third end of the first three-way joint and the second end of the protective sleeve is sealed, and the other is sealedly connected to the connector, and the connector is used to connect to the single crystal optical fiber passing through the protective sleeve.

[0062] As described above, one end of the single crystal optical fiber 1 passes through the first end of the protective sleeve 2 and is connected to the first connector 52 (that is, one end of the single crystal optical fiber 1 is exposed from the protective sleeve 2), and the second end of the protective sleeve 2 is sealed. In this way, useful data can be obtained through the first connector 52. For example, when the first connector 52 is connected to the temperature measurement system, accurate temperature monitoring of the single crystal optical fiber and its contact area during the packaging process can be achieved, which is convenient for timely adjustment of heating operations during the packaging process to ensure packaging quality. In addition, through the protection of the first optical fiber protection structure 6, the optical fiber is not easily damaged or contaminated by the external environment, etc.

[0063] By sealing the third end of the first three-way connector 51 and setting the second connector 53, and connecting the second connector 53 to an external device such as a spectrometer, the optical signal of the single crystal optical fiber 1 can be measured (which can also be considered as a kind of useful data) to evaluate the performance of the single crystal optical fiber 1 after packaging, for example, by analyzing the spectral characteristics of the wavelength distribution and intensity distribution of the optical signal in the optical fiber; for example, during the packaging process, the optical performance of the single crystal optical fiber may be affected by heat treatment, strain or other factors. By connecting to the spectrometer for testing in real time or regularly, these changes can be monitored to ensure that the optical fiber performance meets the expected standards, such as maintaining low loss, high bandwidth or specific spectral transmittance characteristics.

[0064] See also Figure 1 , Figure 3 , Figure 4 and Figure 5 The single crystal optical fiber sensing probe includes a first three-way joint, a first connector and a second connector. The first end of the first three-way joint is connected to the stop valve; the second end of the first three-way joint is connected to the protective sleeve, the third end of the first three-way joint is sealedly connected to the first connector, and the second end of the protective sleeve is sealedly connected to the second connector, so that both ends of the single crystal optical fiber pass through the protective sleeve and are correspondingly connected to the first connector and the second connector.

[0065] As configured above, both ends of the single crystal optical fiber 1 of the single crystal optical fiber sensing probe pass through the protective sleeve and are connected to external devices through the first connector 52 and the second connector 53 respectively, which is more conducive to obtaining useful data.

[0066] In some embodiments, for the optical fiber sensing probe, the protective sleeve includes a heated section; the single crystal optical fiber sensing probe includes two capillaries, which are respectively inserted into the protective sleeve from opposite ends of the protective sleeve and are separated from the heated section.

[0067] As described above, by providing the capillary 8, the capillary 8 can protect the single crystal optical fiber 1. At the same time, the capillary 8 is separated from the heated section 21. During the packaging process, it can be ensured that the performance of the capillary 8 will not be affected by heat.

[0068] In some embodiments, for the optical fiber sensing probe, the length of each capillary extending into the protective sleeve from the end of the protective sleeve is D, 0cm<D≤20cm. For example, 0.5cm, 0.8cm, 1cm, 1.3cm, 1.5cm, 1.8cm, 2cm, 2.3cm, 2.5cm, 2.8cm, 3cm, 3.2cm, 3.4cm, 3.6cm, 3.8cm, 4cm, 4.3cm, 4.5cm, 4.8cm, 5cm, 5.5cm, 5.8cm, 6cm, 6.5cm, 7cm, 7.3cm, 7.5cm, 7.7cm, 8cm, 8.3cm, 8.5cm, 8.7cm, 9cm, 9.2cm, 9.5cm, 9.8 18cm, 18.2cm, 18.5cm, 18.8cm, 19cm, 19.3cm, 19.5cm, 19.8cm or 20cm.

[0069] As set above, since 0cm<D≤20cm, on the one hand, the capillary 8 can protect the single crystal optical fiber 1, and on the other hand, the capillary 8 is far away from the heating section 11, which can prevent the heat from affecting the performance of the capillary 8.

[0070] For the single crystal optical fiber sensing probe, the single crystal optical fiber sensing probe includes a pressure monitor, and the pressure monitor is connected to the passage between the stop valve and the protective sleeve.

[0071] As described above, by setting the pressure monitor 91, the internal gas pressure (also considered as a kind of useful data) can be monitored in real time by the pressure monitor 91, and a gas leakage alarm can be given.

[0072] For the single crystal optical fiber sensing probe, the single crystal optical fiber sensing probe includes a low temperature section, the single crystal optical fiber sensing probe includes an air chamber, and the air chamber is connected to the heated section of the protective sleeve through the low temperature section.

[0073] As described above, by providing the air chamber 92, the air chamber 92 is connected to the heated section 21, so that the air chamber 92 can provide a buffer space for the expanding gas at high temperature, reduce the internal pressure, and reduce the possibility of gas leakage.

[0074] For the single crystal fiber sensing probe, when the single crystal fiber is a sapphire fiber, a single crystal sapphire fiber grating, a single crystal sapphire fiber Fabry-Perot cavity, or a single crystal fiber containing femtosecond laser microprocessing, the protective sleeve is a sapphire tube, or a high-purity alumina ceramic tube; or, when the single crystal fiber is a YAG fiber, a YAG-doped fiber, a single crystal YAG fiber grating, a single crystal YAG fiber Fabry-Perot cavity, or a single crystal fiber containing femtosecond laser microprocessing, the protective sleeve is a YAG single crystal tube.

[0075] Whether it is the single crystal optical fiber sensor probe or the single crystal optical fiber packaging device, the metal fittings 592, the metal tube 591 and other connectors are used to achieve a sealed connection between related components, which makes sealing simpler and the connection more convenient.

[0076] It should be noted that the technical solutions or technical features described in the above embodiments can be combined or supplemented with each other without causing conflicts. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the drawings; all modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. A single crystal optical fiber packaging device, characterized in that: The single crystal optical fiber packaging device comprises a protective sleeve for accommodating the single crystal optical fiber, a stop valve and an air filling device, wherein the protective sleeve is dense and airtight, the material of the protective sleeve will not chemically react with the single crystal optical fiber, and the melting point of the protective sleeve is not lower than the melting point of the single crystal optical fiber; the air filling device is connected with the protective sleeve through the stop valve, and when the stop valve is opened, the protective sleeve is evacuated or a protective gas is filled into the protective sleeve; The protective sleeve includes a heated section; the single crystal optical fiber packaging device includes two capillaries, which are respectively inserted into the protective sleeve from opposite ends thereof and are separated from the heated section; the single crystal optical fiber passes from the capillary at one end through the interior of the protective sleeve into the capillary at the other end.

2. The single crystal optical fiber packaging device according to claim 1, characterized in that: The single crystal optical fiber packaging device comprises a first three-way joint and a connector, wherein the first end of the first three-way joint is connected to the stop valve, and the second end of the first three-way joint is connected to the first end of the protective sleeve; one of the third end of the first three-way joint and the second end of the protective sleeve is sealed, and the other is sealed and connected to the connector, and the connector is used to connect to the single crystal optical fiber passing through the protective sleeve; Alternatively, the single crystal optical fiber packaging device includes a first three-way joint, a first connector and a second connector, the first end of the first three-way joint is connected to the stop valve; the second end of the first three-way joint is connected to the protective sleeve, the third end of the first three-way joint is sealedly connected to the first connector, and the second end of the protective sleeve is sealedly connected to the second connector, so that both ends of the single crystal optical fiber pass through the protective sleeve and are correspondingly connected to the first connector and the second connector.

3. The single crystal optical fiber packaging device according to claim 1, characterized in that: The inflation device comprises a second three-way joint, a vacuum pump, an air supply device and a valve, wherein: One of the vacuum pump and the air supply device is connected to the first end of the second three-way joint through a valve, and the other of the vacuum pump and the air supply device is connected to the second end of the second three-way joint; the third end of the second three-way joint is connected to the stop valve.

4. The single crystal optical fiber packaging device according to claim 1, characterized in that: From the end of the protective sleeve, the length of each capillary extending into the protective sleeve is D, 0cm<D≤20cm.

5. The single crystal optical fiber packaging device according to claim 1, characterized in that: The single crystal optical fiber packaging device includes a pressure monitor connected to the passage between the stop valve and the protective sleeve; And / or, the single crystal optical fiber packaging device includes a low temperature section, the single crystal optical fiber packaging device includes an air chamber, and the air chamber is connected to the heated section of the protective sleeve through the low temperature section.

6. The single crystal optical fiber packaging device according to claim 1, characterized in that: When the single crystal optical fiber is a sapphire optical fiber, a single crystal sapphire optical fiber grating, a single crystal sapphire optical fiber Fabry-Perot cavity, or a single crystal optical fiber containing femtosecond laser micromachining, the protective sleeve is a sapphire tube, or a high-purity alumina ceramic tube; When the single crystal optical fiber is a YAG optical fiber, a YAG doped optical fiber, a single crystal YAG fiber grating, a single crystal YAG optical fiber Fabry-Perot cavity or a single crystal optical fiber containing femtosecond laser micromachining, the protective sleeve is a YAG single crystal tube.

7. A single crystal optical fiber sensor probe, characterized in that: The single crystal optical fiber sensing probe comprises a single crystal optical fiber, a protective sleeve and a stop valve, wherein the single crystal optical fiber is passed through the protective sleeve, the protective sleeve is dense and airtight, the material of the protective sleeve will not chemically react with the material of the single crystal optical fiber, and the melting point of the protective sleeve is not lower than the melting point of the single crystal optical fiber; the stop valve is connected to the protective sleeve to open and close the protective sleeve; The protective sleeve includes a heated section; the single crystal optical fiber sensing probe includes two capillaries, which are respectively inserted into the protective sleeve from opposite ends thereof and are separated from the heated section; the single crystal optical fiber passes from the capillary at one end through the interior of the protective sleeve and into the capillary at the other end.

8. The single crystal optical fiber sensing probe according to claim 7, characterized in that: The single crystal optical fiber sensing probe comprises a first three-way joint and a connector, wherein the first end of the first three-way joint is connected to the stop valve, and the second end of the first three-way joint is connected to the first end of the protective sleeve; one of the third end of the first three-way joint and the second end of the protective sleeve is sealed, and the other is sealed and connected to the connector, and the connector is used to connect to the single crystal optical fiber passing through the protective sleeve; Alternatively, the single crystal optical fiber sensing probe includes a first three-way joint, a first connector and a second connector, the first end of the first three-way joint is connected to the stop valve; the second end of the first three-way joint is connected to the protective sleeve, the third end of the first three-way joint is sealedly connected to the first connector, and the second end of the protective sleeve is sealedly connected to the second connector, so that both ends of the single crystal optical fiber pass through the protective sleeve and are correspondingly connected to the first connector and the second connector.

9. The single crystal optical fiber sensing probe according to claim 7, characterized in that: From the end of the protective sleeve, the length of each capillary extending into the protective sleeve is D, 0cm<D≤20cm.

10. The single crystal optical fiber sensing probe according to claim 7, characterized in that: The single crystal optical fiber sensing probe includes a pressure monitor connected to the passage between the stop valve and the protective sleeve; And / or, the single crystal optical fiber sensing probe comprises a low temperature section, the single crystal optical fiber sensing probe comprises an air chamber, and the air chamber is connected to the heated section of the protective sleeve through the low temperature section.

11. The single crystal optical fiber sensing probe according to claim 7, characterized in that: When the single crystal optical fiber is a sapphire optical fiber, a single crystal sapphire optical fiber grating, a single crystal sapphire optical fiber Fabry-Perot cavity or a single crystal optical fiber containing femtosecond laser micromachining, the protective sleeve is a sapphire tube, or a high-purity alumina ceramic tube; Alternatively, when the single crystal optical fiber is a YAG optical fiber, a YAG-doped optical fiber, a single crystal YAG fiber grating, a single crystal YAG optical fiber Fabry-Perot cavity, or a single crystal optical fiber containing femtosecond laser micromachining, the protective sleeve is a YAG single crystal tube.

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