Heavy water vapor replacement device, spectral measurement system and method for reducing water peak absorption loss of hollow-core optical fiber

Abstract

The invention relates to the technical field of optical fiber manufacturing, and discloses a heavy water vapor replacement device, a spectral measurement system and a method for reducing water peak absorption loss of a hollow-core optical fiber. The method for reducing the water peak absorption loss of the hollow-core optical fiber is realized by using a heavy water vapor replacement device, the effectiveness is verified through a spectral measurement system, the heavy water vapor replacement device comprises a vapor generation assembly, a first gas cavity assembly and a gas extraction assembly, the gas extraction assembly firstly vacuumizes the interior of a fiber core, and the vapor generation assembly generates heavy water vapor; heavy water vapor is filled in a fiber core of the hollow-core optical fiber through the first gas cavity assembly, the heavy water vapor is prevented from being mixed with gas reserved in the fiber core, it is guaranteed that the fiber core of the hollow-core optical fiber is completely filled with the heavy water vapor, an absorption peak is weakened, especially interference to S-band communication is greatly reduced, hydroxyl formed by heavy water molecules has stable chemical properties, and the service life of the hollow-core optical fiber is prolonged. Secondary adsorption of common water vapor is effectively delayed, and the transmission performance of the optical fiber is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber manufacturing, and in particular to a heavy water vapor replacement device, a spectrum measurement system and a method for reducing water peak absorption loss of hollow core optical fiber. Background Art

[0002] In long-distance communication applications, the water peak absorption loss of hollow-core optical fibers cannot be ignored and will affect the transmission performance of optical fiber communication systems.

[0003] The absorption loss of hollow core optical fiber includes the absorption loss of the glass material forming the core and the absorption loss of the gas molecules in the core. The absorption loss of the glass material mainly comes from the absorption loss of hydroxyl ions, and the absorption loss of gas molecules mainly comes from the loss of water vapor absorption. Hydroxyl ions and water vapor absorb electromagnetic radiation by forming multiple absorption peaks through rotational transitions and vibrations between molecules and their combination, especially the absorption effect of electromagnetic waves in the E band with a wavelength of 1360nm-1460nm and the S band with a wavelength of 1460nm-1530nm, forming a "water peak effect" and causing distortion of communication signals.

[0004] In the prior art, there are two solutions to reduce the water peak absorption loss of hollow core optical fibers: the first is to perform a dehydroxylation process during the preparation of the glass material; the second is to purge the fiber core with dry inert gas or nitrogen. Both of the above methods are difficult to completely remove the water vapor in the fiber core. At the same time, during the use of the optical fiber, water vapor in the environment may still invade the fiber core again, resulting in repeated water peak absorption loss problems caused by the "water peak effect", which is difficult to completely remove.

[0005] Therefore, there is an urgent need to provide a heavy water vapor replacement device, a spectrum measurement system and a method for reducing the water peak absorption loss of hollow core optical fiber to solve the above problems. Summary of the invention

[0006] Based on the above, a first object of the present invention is to provide a heavy water vapor replacement device to at least solve one of the above problems.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A heavy water vapor replacement device, comprising:

[0009] A gas extraction component capable of extracting gas retained in the core of the hollow-core optical fiber;

[0010] A steam generating assembly, comprising a liquid storage container and a bubbler, wherein liquid water is stored in a closed cavity of the liquid storage container, wherein the liquid water is liquid ordinary water or liquid heavy water, and the bubbler is capable of passing a purge gas into the liquid water;

[0011] The first gas cavity assembly comprises an optical fiber docking assembly, an air joint and a T-shaped tube, wherein the opposite ends of the optical fiber docking assembly can respectively connect a hollow-core optical fiber and a solid-core optical fiber, the optical fiber docking assembly is sealed and installed in the air-filled cavity of the T-shaped tube, and the air joint is respectively connected to the air-filled cavity and the closed cavity.

[0012] Furthermore, the optical fiber docking assembly includes a first connector, a second connector and a sleeve, the first connector and the second connector are connected via the sleeve, the first connector can be connected to the hollow core optical fiber, and the second connector can be connected to the solid core optical fiber.

[0013] Furthermore, the sleeve has a gap, and the gap can be communicated with the inflation cavity and the first joint respectively.

[0014] Furthermore, the bubbler has an air inlet end and an air outlet end which are connected, the air inlet end can be introduced with a purge gas, and the air outlet end is immersed in the liquid water.

[0015] Furthermore, the enclosed cavity has a steam production port, and the steam production port is communicated with the gas joint.

[0016] Furthermore, the vacuum assembly includes a vacuum pump and a second gas chamber assembly, the structure of the second gas chamber assembly is the same as that of the first gas chamber assembly, and the gas joint of the second gas chamber assembly is connected to the vacuum pump.

[0017] Based on the above, a second object of the present invention is to provide a method for reducing water peak absorption loss of hollow core optical fiber, so as to solve at least one of the above problems.

[0018] To achieve the above object, the present invention adopts the following technical solutions:

[0019] A method for reducing the water peak absorption loss of hollow core optical fiber by using the heavy water vapor replacement device described in any one of the above schemes comprises the following steps:

[0020] The gas retained in the core of the hollow-core optical fiber is extracted by using an exhaust assembly;

[0021] Passing the purge gas into the liquid heavy water through a bubbler to form heavy water vapor in the closed chamber;

[0022] The heavy water vapor enters the air filling cavity of the T-tube through the air joint, and enters the optical fiber docking assembly and the hollow-core optical fiber from the air filling cavity, so as to fill the core of the hollow-core optical fiber with the heavy water vapor.

[0023] Furthermore, the pressure of the heavy water vapor filled into the hollow core optical fiber is greater than 5 bar.

[0024] Furthermore, the purge gas is an inert gas or nitrogen.

[0025] Based on the above, a third object of the present invention is to provide a spectrum measurement system to solve at least one of the above problems.

[0026] To achieve the above object, the present invention adopts the following technical solutions:

[0027] A spectral measurement system for verifying the effectiveness of the method for reducing water peak absorption loss of hollow core optical fiber described in any of the above schemes, comprising:

[0028] Fiber optic couplers;

[0029] Two sets of heavy water vapor replacement devices, whose first gas chamber components correspond to liquid heavy water and liquid ordinary water respectively;

[0030] A broadband light source is connected to two sets of heavy water vapor replacement devices respectively through optical fiber couplers;

[0031] The spectrometer is respectively connected to the exhaust components in the two groups of heavy water vapor replacement devices.

[0032] The beneficial effects of the present invention are:

[0033] The present invention provides a heavy water vapor replacement device, comprising a vapor production component, a first gas cavity component and an exhaust component, wherein the exhaust component can extract the gas retained in the core of a hollow-core optical fiber, the vapor production component comprises a liquid storage container and a bubbler, liquid water is stored in a closed cavity of the liquid storage container, and the liquid water can be liquid ordinary water or liquid heavy water, the bubbler can pass a purge gas into the liquid water, the first gas cavity component comprises an optical fiber docking component, an air joint and a T-tube, the opposite ends of the optical fiber docking component can respectively connect the hollow-core optical fiber and the solid-core optical fiber, the optical fiber docking component is sealed and installed in the inflation cavity of the T-tube, and the air joint is respectively connected to the inflation cavity and the sealed cavity. The heavy water vapor replacement device can replace the gas retained in the core of the hollow-core optical fiber with heavy water vapor produced by the steam-generating component, thereby changing the atomic composition of the gas molecules in the core and the hydroxyl groups of the glass wall, and the absorption peak of the heavy water molecules is red-shifted to a longer wavelength, and the absorption intensity is significantly reduced; the heavy water hydroxyl groups are adsorbed on the glass wall surface of the hollow-core optical fiber, which plays a passivation role, reduces the secondary adsorption of ordinary water hydroxyl groups and ordinary water vapor during the use of the hollow-core optical fiber, reduces the water peak absorption loss of the hollow-core optical fiber, and improves the transmission performance of the hollow-core optical fiber; there is no need to perform dehydroxylation treatment during the preparation stage of the glass raw material of the hollow-core optical fiber, and there is no need to change the glass raw material, which is economical and practical.

[0034] The present invention provides a method for reducing water peak absorption loss of hollow core optical fiber, which is implemented by using the heavy water vapor replacement device, and comprises the following steps:

[0035] The gas retained in the core of the hollow-core optical fiber is extracted by using an exhaust assembly;

[0036] Passing the purge gas into the liquid heavy water through a bubbler to form heavy water vapor in the closed chamber;

[0037] The heavy water vapor enters the air filling cavity of the T-tube through the air joint, and enters the optical fiber docking assembly and the hollow-core optical fiber from the air filling cavity, so as to fill the core of the hollow-core optical fiber with the heavy water vapor.

[0038] The vacuum assembly first evacuates the fiber core to prevent the heavy water vapor from mixing with the gas remaining in the fiber core to ensure a more thorough replacement, that is, to ensure that the heavy water vapor completely fills the core of the hollow-core optical fiber, weakening the absorption peak, especially greatly reducing interference with S-band communications. The hydroxyl group formed by heavy water molecules has stable chemical properties, which effectively delays the secondary adsorption of ordinary water vapor and improves the transmission performance of the optical fiber.

[0039] The present invention provides a spectrum measurement system, including an optical fiber coupler, two groups of heavy water vapor replacement devices, a broadband light source and a spectrometer, wherein the first gas cavity components of the two groups of heavy water vapor replacement devices correspond to liquid heavy water and liquid ordinary water respectively, the broadband light source is connected to the two groups of heavy water vapor replacement devices through the optical fiber coupler, and the spectrometer is connected to the exhaust components in the two groups of heavy water vapor replacement devices respectively. By measuring the transmission spectra of two hollow-core optical fibers, the effects of heavy water vapor and ordinary water vapor on water peak absorption are directly compared to verify the effectiveness of the method for reducing the water peak absorption loss of the hollow-core optical fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0041] Figure 1 It is a schematic diagram of the loss classification of hollow-core optical fibers and the replacement principle of the method for reducing the water peak absorption loss of hollow-core optical fibers provided by a specific embodiment of the present invention;

[0042] Figure 2 It is a structural schematic diagram of a heavy water vapor replacement device provided in a specific embodiment of the present invention;

[0043] Figure 3 is a structural schematic diagram of a first gas chamber assembly provided in a specific embodiment of the present invention;

[0044] Figure 4 is an exploded view of a first gas chamber assembly provided in a specific embodiment of the present invention;

[0045] Figure 5is a structural schematic diagram of a spectrum measurement system provided by a specific embodiment of the present invention;

[0046] Figure 6 It is the absorption spectrum of liquid heavy water and liquid ordinary water at 1200nm-2600nm.

[0047] In the figure:

[0048] 100. Heavy water vapor replacement device; 200. Hollow core optical fiber; 300. Broadband light source; 400. Optical fiber coupler; 401. Single pin; 402. Double pin; 500. Spectrometer; 600. Solid core optical fiber;

[0049] 1. Steam generating assembly; 2. First gas chamber assembly; 3. Air extraction assembly;

[0050] 11. Liquid storage container; 12. Liquid water; 13. Bubbler; 14. Steam generating pipe; 21. Optical fiber docking assembly; 22. Gas joint; 23. T-shaped pipe; 31. Vacuum pump; 32. Second gas chamber assembly; 33. Vacuum pipe;

[0051] 111, closed chamber; 112, steam generating port; 121, liquid heavy water; 122, liquid ordinary water; 131, air inlet end; 132, air outlet end; 211, first joint; 212, second joint; 213, sleeve; 231, air-filled chamber;

[0052] 2111. Insert core; 2112. Insert handle; 2131. Gap. DETAILED DESCRIPTION

[0053] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention are shown in the accompanying drawings, rather than all structures.

[0054] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, it can be a mechanical connection or an electrical connection, it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] In the description of the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include the first feature being in direct contact with the second feature, or may include the first feature being in contact with the second feature through another feature between them instead of being in direct contact. Moreover, a first feature being "above", "above" and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0056] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0057] like Figure 1-Figure 4 As shown, this embodiment provides a heavy water vapor replacement device 100 for replacing the retained gas in the core of the hollow core optical fiber 200 with heavy water vapor to improve the transmission performance of the hollow core optical fiber 200.

[0058] like Figure 1 As shown, the loss of the hollow-core optical fiber includes leakage loss, absorption loss and scattering loss. The absorption loss includes material absorption loss and gas absorption loss. The material absorption loss includes transition metal ion absorption loss and hydroxyl ion absorption loss of glass material. The gas absorption loss includes water vapor absorption loss and other gas absorption losses. The heavy water vapor replacement device 100 provided in this embodiment replaces the retained gas in the core of the hollow-core optical fiber 200 with heavy water vapor. By utilizing the characteristic that the isotope of hydrogen atom (H) - deuterium (D) has the same chemical properties, heavy water (DO) vapor is introduced into the hollow-core optical fiber to replace the ordinary water vapor in the core of the hollow-core optical fiber. The absorption peak of the heavy water molecule is red-shifted to a longer wavelength, which significantly reduces the water peak absorption, thereby reducing the water vapor absorption loss; at the same time, the hydroxyl ions on the surface of the glass wall forming the core are replaced with heavy water hydroxyl ions. The treated hollow-core optical fiber exhibits a certain degree of passivation effect on the water vapor in the application environment, delaying the influence of water vapor re-adsorption on the optical fiber performance, thereby reducing the hydroxyl ion absorption loss of the glass material.

[0059] The heavy water vapor replacement device 100 includes a steam production component 1, a first gas chamber component 2 and an exhaust component 3. The exhaust component 3 can extract the gas retained in the core of the hollow-core optical fiber 200. The steam production component 1 includes a liquid storage container 11 and a bubbler 13. Liquid water 12 is stored in the closed chamber 111 of the liquid storage container 11. The liquid water 12 can be liquid ordinary water 122 or liquid heavy water 121. The bubbler 13 can pass the purge gas into the liquid water 12. The first gas chamber component 2 includes an optical fiber docking component 21, an air joint 22 and a T-tube 23. The opposite ends of the optical fiber docking component 21 can respectively connect the hollow-core optical fiber 200 and the solid-core optical fiber 600. The optical fiber docking component 21 is sealed and installed in the inflation chamber 231 of the T-tube 23. The air joint 22 is respectively connected to the inflation chamber 231 and the sealed chamber 111. The heavy water vapor replacement device 100 can replace the gas retained in the core of the hollow-core optical fiber 200 with the heavy water vapor produced by the steam-generating component 1, change the atomic composition of the gas molecules and the glass wall hydroxyl groups in the core, and red-shift the absorption peak of the heavy water molecules to a longer wavelength, and significantly reduce the absorption intensity; the heavy water hydroxyl groups are adsorbed on the glass wall surface of the hollow-core optical fiber 200, play a passivation role, reduce the secondary adsorption of ordinary water hydroxyl groups and ordinary water vapor during the use of the hollow-core optical fiber 200, reduce the water peak absorption loss of the hollow-core optical fiber 200, and improve the transmission performance of the hollow-core optical fiber 200; there is no need to perform dehydroxylation treatment during the glass raw material preparation stage of the hollow-core optical fiber 200, and there is no need to change the glass raw materials, which is economical and practical.

[0060] like Figure 2 As shown, the bubbler 13 has an air inlet end 131 and an air outlet end 132 which are connected to each other. The air inlet end 131 can be introduced with a purge gas, and the air outlet end 132 is immersed in the liquid water 12 .

[0061] Furthermore, the steam generating component 1 also includes a gas cylinder, in which a purge gas is stored. The gas cylinder can be connected to the gas inlet end 131 so that the purge gas can be passed into the bubbler 13 to generate replacement water vapor.

[0062] Specifically, the purge gas may be nitrogen or an inert gas, which will not affect the gas replacement in the fiber core, thereby ensuring the transmission performance of the hollow-core optical fiber 200 .

[0063] Furthermore, after the bubbler 13 is installed on the liquid storage container 11 , the upper end of the liquid storage container 11 can be sealed by a cover or the like to form a closed cavity 111 , so that the generated replacement water vapor can be smoothly filled into the first gas chamber assembly 2 .

[0064] Specifically, the air inlet end 131 of the bubbler 13 is located outside the sealed cavity 111 of the liquid storage container 11 so that the air inlet end 131 is connected to the gas cylinder.

[0065] Furthermore, the sealed chamber 111 has a steam generating port 112 , which is located above the liquid level of the liquid water 12 stored in the sealed chamber 111 . The steam generating port 112 is connected to the gas joint 22 so that the generated replacement water vapor can be filled into the gas joint 22 .

[0066] When the liquid water 12 is liquid heavy water 121 , the replacement water vapor generated by the steam production component 1 is heavy water vapor; when the liquid water 12 is liquid ordinary water 122 , the replacement water vapor generated by the steam production component 1 is ordinary water vapor.

[0067] Furthermore, the steam generating assembly 1 further comprises a steam generating pipe 14, and the steam generating port 112 is connected to the gas connector 22 via the steam generating pipe 14. The steam generating pipe 14 needs to be dehumidified in advance to prevent the water vapor in the steam generating pipe 14 from interfering with the replacement result.

[0068] Furthermore, the gas extraction component 3 includes a vacuum pump 31 and a second gas chamber component 32. The structure of the second gas chamber component 32 is the same as that of the first gas chamber component 2. The gas joint of the second gas chamber component 32 is connected to the vacuum pump 31. The gas extraction component 3 is set to evacuate the fiber core to prevent the heavy water vapor from mixing with the gas retained in the fiber core, so as to ensure a more thorough replacement, that is, to ensure that the heavy water vapor completely fills the fiber core of the hollow-core optical fiber 200.

[0069] Furthermore, the exhaust assembly 3 further includes an exhaust pipe 33, and the gas joint 22 of the second gas chamber assembly 32 is connected to the vacuum pump 31 through the exhaust pipe 33. The exhaust pipe 33 needs to be dehumidified in advance to prevent the water vapor in the exhaust pipe 33 from interfering with the replacement result.

[0070] like Figure 3 and Figure 4 As shown, the optical fiber docking assembly 21 includes a first connector 211, a second connector 212 and a sleeve 213. The first connector 211 and the second connector 212 are connected through the sleeve 213. The first connector 211 can be connected to the hollow core optical fiber 200, and the second connector 212 can be connected to the solid core optical fiber 600.

[0071] Specifically, the first connector 211 and the second connector 212 are installed in the air filling cavity 231 of the T-tube 23 by means of UV glue sealing to prevent the heavy water vapor from flowing out of the air filling cavity 231 so as to fill the heavy water vapor into the core of the hollow core optical fiber 200.

[0072] Furthermore, the sleeve 213 has a slit 2131, and the slit 2131 can be respectively connected to the gas-filled cavity 231 and the first joint 211. Such a configuration can ensure that the heavy water vapor enters the slit 2131 from the gas-filled cavity 231, then enters the first joint 211, and then enters the core of the hollow-core optical fiber 200, so that the heavy water vapor fills the core of the hollow-core optical fiber 200.

[0073] Furthermore, the first connector 211 and the second connector 212 may also have gaps, the purpose of which is to facilitate the entry of heavy water vapor into the core of the hollow-core optical fiber 200 to facilitate the completion of the replacement process.

[0074] Specifically, the width of the gap 2131 of the sleeve 213 is less than 1 mm, the width of the gap of the first joint 211 is within 100 microns, and the width of the gap of the second joint 212 is within 100 microns.

[0075] Furthermore, the second connector 212 is in the TEC mode field, which facilitates coupling with the hollow core optical fiber 200 .

[0076] Furthermore, the distance between the TEC mode field where the second connector 212 is located and the hollow core optical fiber 200 is within 100 microns, which ensures the coupling efficiency between the TEC mode field and the hollow core optical fiber 200 and facilitates inflation.

[0077] Furthermore, the first connector 211 includes a ferrule 2111 and a handle 2112 , the ferrule 2111 is fixedly mounted on the handle 2112 , the ferrule 2111 is connected to the sleeve 213 , and the hollow-core optical fiber 200 is inserted into the handle 2112 and into the ferrule 2111 .

[0078] Specifically, after the hollow-core optical fiber 200 is inserted into the ferrule 2111 , the hollow-core optical fiber 200 is fixed in the insertion handle 2112 by ultraviolet glue.

[0079] In this embodiment, the structure of the second connector 212 is similar to that of the first connector 211 , with the only difference being that the solid core optical fiber 600 passes through the insert handle 2112 of the second connector 212 and is inserted into the insert core 2111 of the second connector 212 .

[0080] In this embodiment, two opposite ends of the sleeve 213 are fixedly connected to the ferrule 2111 of the first connector 211 and the ferrule 2111 of the second connector 212 , respectively.

[0081] Specifically, the sleeve 213 and the ferrule 2111 of the first connector 211 as well as the sleeve 213 and the ferrule 2111 of the second connector 212 are fixedly connected by ultraviolet glue to prevent the docking coupling jitter caused by excessive air pressure during the vacuuming process, prevent additional insertion loss, and ensure the accuracy of the replacement result.

[0082] In this embodiment, the structure of the second gas chamber component 32 is the same as that of the first gas chamber component 2. The first connector of the second gas chamber component 32 is connected to the hollow core optical fiber 200, the second connector of the second gas chamber component 32 is connected to the solid core optical fiber 600, and the gas connector of the second gas chamber component 32 is connected to the vacuum pump 31. The specific structure will not be repeated here.

[0083] Furthermore, the gas connector 22 and the T-shaped tube 23 can be connected by threads, which is plug-and-play and more convenient and quick.

[0084] Furthermore, the first gas chamber component 2 and the second gas chamber component 32 are dehumidified as a whole to prevent the gas in the first gas chamber component 2 and the second gas chamber component 32 from affecting the replacement result, thereby ensuring a more thorough replacement.

[0085] The heavy water vapor replacement device 100 is applicable to all hollow core optical fibers 200, including anti-resonance hollow core optical fibers, photonic crystal bandgap hollow core optical fibers, etc., which are not limited in this embodiment.

[0086] In practical applications, the core of the hollow-core optical fiber 200 is filled with heavy water vapor using the heavy water vapor replacement device 100 to form a passivation-like film attached to the glass wall of the core. Then, the end face of the hollow-core optical fiber 200 is sealed to prevent the core of the hollow-core optical fiber 200 from contacting the environment and avoid secondary adsorption of environmental water vapor.

[0087] This embodiment also provides a method for reducing the water peak absorption loss of hollow core optical fiber, which is implemented by using the heavy water vapor replacement device 100, and includes the following steps:

[0088] The gas retained in the core of the hollow core optical fiber 200 is extracted by using the exhaust assembly 3;

[0089] The purge gas is passed into the liquid heavy water 121 through the bubbler 13, and heavy water vapor is formed in the closed chamber 111;

[0090] The heavy water vapor enters the gas filling cavity 231 of the T-tube 23 through the gas joint 22 , and enters the optical fiber docking assembly 21 and the hollow-core optical fiber 200 from the gas filling cavity 231 , so as to fill the core of the hollow-core optical fiber 200 with the heavy water vapor.

[0091] The vacuum assembly 3 first evacuates the fiber core to prevent the heavy water vapor from mixing with the gas remaining in the fiber core to ensure a more thorough replacement, that is, to ensure that the heavy water vapor completely fills the fiber core of the hollow-core optical fiber 200, weakens the absorption peak, and especially greatly reduces the interference of S-band communication. The hydroxyl group formed by the heavy water molecules has stable chemical properties, which effectively delays the secondary adsorption of ordinary water vapor and improves the transmission performance of the optical fiber.

[0092] The step of passing the purge gas into the liquid heavy water 121 through the bubbler 13 and forming heavy water vapor in the closed chamber 111 includes the following specific steps:

[0093] The purge gas in the gas cylinder enters the bubbler 13 through the gas inlet end 131 , and then is discharged from the gas outlet end 132 of the bubbler 13 , and then mixes and dissolves with the liquid heavy water 121 , and forms heavy water vapor above the liquid surface of the liquid heavy water 121 .

[0094] Furthermore, the pressure of the heavy water vapor filled into the hollow core optical fiber 200 is greater than 5 bar, which can increase the rate at which the heavy water vapor replaces the ordinary water vapor.

[0095] like Figure 5 As shown, this embodiment also provides a spectrum measurement system, including a fiber coupler 400, two sets of heavy water vapor replacement devices 100, a broadband light source 300 and a spectrometer 500, the first gas chamber components 2 of the two sets of heavy water vapor replacement devices 100 correspond to liquid heavy water 121 and liquid ordinary water 122 respectively, the broadband light source 300 is connected to the two sets of heavy water vapor replacement devices 100 respectively through the fiber coupler 400, and the spectrometer 500 is connected to the exhaust components 3 in the two sets of heavy water vapor replacement devices 100 respectively. By measuring the transmission spectra of the two hollow-core optical fibers 200, the effects of the liquid heavy water 121 vapor and the liquid ordinary water 122 vapor on the water peak absorption are directly compared to verify the effectiveness of the method for reducing the water peak absorption loss of the hollow-core optical fiber.

[0096] Furthermore, the fiber coupler 400 has a single pin 401 and a double pin 402 , the single pin 401 is fused with the broadband light source 300 , and the two pins of the double pin 402 are respectively connected to the second connectors 212 in the two groups of heavy water vapor replacement devices 100 through solid core optical fibers 600 .

[0097] Specifically, the two pins of the double pin 402 are fused with the two solid core optical fibers 600 respectively.

[0098] Furthermore, the spectrometer 500 is connected to the exhaust components 3 in the two heavy water vapor replacement devices 100 through the solid core optical fiber 600.

[0099] In this embodiment, the splicing loss is less than 0.01 dB and can be ignored.

[0100] In this embodiment, the solid core optical fiber 600 may be a single-mode solid core optical fiber SMF-28.

[0101] The broadband light source 300 is connected to the second connector 212 through a single-mode jumper and then coupled into the hollow-core optical fiber 200. Because the mode field of the second connector 212 is similar to the mode field of the hollow-core optical fiber 200, the coupling efficiency is high and the loss is reduced.

[0102] The solid core optical fiber 600 is selected to realize the connection between the heavy water vapor replacement device 100 and the optical fiber coupler 400 and the heavy water vapor replacement device 100 and the spectrometer 500 in order to ensure that the coupling condition of the spectrometer 500 does not change and to ensure the accuracy of the verification result.

[0103] At the same time, ordinary water vapor and heavy water vapor of the same flow rate are respectively injected into two hollow-core optical fibers 200 of equal length to ensure the consistency of experimental conditions.

[0104] The final output spectrum obtained by the spectrum measurement system is as follows Figure 6 As shown, it can be seen that the replacement process of the same-order phonon absorption will cause the absorption peak to red-shift. At the same time, the short-wave third-order phonon absorption will red-shift to the vicinity of this position, but the absorption intensity is one order of magnitude smaller, that is, the absorption intensity is significantly lower than that of ordinary water; the absorption spectrum of liquid heavy water 121 is broadened, which has a passivating effect on the glass wall in the core of the hollow-core optical fiber 200, delaying the secondary adsorption of environmental water vapor, and improving the transmission performance of the hollow-core optical fiber 200.

[0105] In this embodiment, the absorption peak of ordinary water vapor at 1470nm is red-shifted to around 2000nm to form a heavy water absorption peak, thereby reducing the interference of water vapor absorption on S-band communication. The wavelength of the heavy water absorption peak formed after the absorption peak of ordinary water vapor at 1470nm is red-shifted is related to the molecular vibration intensity of heavy water vapor. Since the heavy water atom has a larger mass and a smaller vibration intensity, the frequency becomes smaller and the absorption wavelength becomes longer.

[0106] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A heavy water vapor replacement device, characterized in that: include: A gas extraction component (3) capable of extracting gas retained in the core of the hollow-core optical fiber (200); A steam generating assembly (1) comprises a liquid storage container (11) and a bubbler (13), wherein liquid water (12) is stored in a sealed chamber (111) of the liquid storage container (11), wherein the liquid water (12) is liquid ordinary water (122) or liquid heavy water (121), and the bubbler (13) is capable of passing a purge gas into the liquid water (12); A first gas chamber component (2), comprising an optical fiber docking component (21), an air joint (22) and a T-shaped tube (23); the two opposite ends of the optical fiber docking component (21) are respectively capable of connecting a hollow core optical fiber (200) and a solid core optical fiber (600); the optical fiber docking component (21) is sealed and installed in an air-filled chamber (231) of the T-shaped tube (23); and the air joint (22) is respectively connected to the air-filled chamber (231) and the sealed chamber (111).

2. The heavy water vapor replacement device according to claim 1, characterized in that: The optical fiber docking assembly (21) comprises a first connector (211), a second connector (212) and a sleeve (213); the first connector (211) and the second connector (212) are connected via the sleeve (213); the first connector (211) can be connected to the hollow core optical fiber (200), and the second connector (212) can be connected to the solid core optical fiber (600).

3. The heavy water vapor replacement device according to claim 2, characterized in that: The sleeve (213) has a gap (2131), and the gap (2131) can be communicated with the inflation cavity (231) and the first joint (211) respectively.

4. The heavy water vapor replacement device according to claim 1, characterized in that: The bubbler (13) has an air inlet end (131) and an air outlet end (132) which are connected to each other. The air inlet end (131) can be fed with a purge gas, and the air outlet end (132) is immersed in the liquid water (12).

5. The heavy water vapor replacement device according to claim 1, characterized in that: The sealed cavity (111) has a steam production port (112), the steam production port (112) is located above the liquid surface of the liquid water (12), and the steam production port (112) is connected to the gas joint (22).

6. The heavy water vapor replacement device according to claim 1, characterized in that: The vacuum assembly (3) comprises a vacuum pump (31) and a second gas chamber assembly (32); the structure of the second gas chamber assembly (32) is the same as that of the first gas chamber assembly (2); and the gas joint of the second gas chamber assembly (32) is connected to the vacuum pump (31).

7. A method for reducing water peak absorption loss of hollow core optical fiber by using the heavy water vapor replacement device according to any one of claims 1 to 6, characterized in that: The steps include: Using a gas extraction component (3) to extract the gas retained in the core of the hollow-core optical fiber (200); Passing the purge gas into the liquid heavy water (121) through the bubbler (13) to form heavy water vapor in the closed chamber (111); The heavy water vapor enters the gas filling cavity (231) of the T-shaped tube (23) through the gas joint (22), and enters the optical fiber docking assembly (21) and the hollow-core optical fiber (200) from the gas filling cavity (231), so as to fill the core of the hollow-core optical fiber (200) with the heavy water vapor.

8. The method for reducing water peak absorption loss of hollow core optical fiber according to claim 7, characterized in that: The pressure of heavy water vapor filled into the hollow core optical fiber (200) is greater than 5 bar.

9. The method for reducing water peak absorption loss of hollow core optical fiber according to claim 7, characterized in that: The purge gas is an inert gas or nitrogen.

10. A spectrum measurement system for verifying the effectiveness of the method for reducing water peak absorption loss of hollow core optical fiber according to any one of claims 7 to 9, characterized in that: include: Fiber optic coupler (400); Two sets of heavy water vapor replacement devices (100), wherein the first gas chamber components (2) correspond to liquid heavy water (121) and liquid ordinary water (122) respectively; A broadband light source (300) is connected to two sets of heavy water vapor replacement devices (100) respectively through optical fiber couplers (400); The spectrometer (500) is respectively connected to the exhaust components (3) in the two groups of heavy water vapor replacement devices (100).

Images