A low-loss ultraviolet fiber-bundle device and a method for manufacturing the same

Abstract

The application belongs to the technical field of optical devices, and particularly relates to a low-attenuation ultraviolet fiber bundle device and a preparation method thereof. The ultraviolet fiber bundle device is composed of a plurality of ultraviolet fibers arranged in a hollow capillary in a close packing mode. The plurality of ultraviolet fibers are inserted into the hollow capillary, the capillary is subjected to heat fusion and tapering, so that the plurality of ultraviolet fibers are bound in the tapering capillary to form the ultraviolet fiber bundle arranged closely, and then the ultraviolet fiber bundle is subjected to high-pressure hydrogen loading treatment to form the low-attenuation ultraviolet fiber bundle device. The prepared ultraviolet fiber bundle device has the characteristics of high temperature resistance and low attenuation, can effectively improve the transmission power of the ultraviolet fiber bundle, and meets the application requirement of ultraviolet light transmission.

Description

Technical Field

[0001] This invention belongs to the field of ultraviolet fiber technology, specifically relating to an ultraviolet beam device and its fabrication method. Background Technology

[0002] Ultraviolet (UV) fiber bundles have applications in various fields, such as pixel transmission, illumination, UV curing, and UV beam exposure in semiconductor applications, as well as photolithography. However, the fiber bundling method for UV beams is limited by the materials used in the bundle. Due to the materials themselves, the bundles cannot withstand long-term use at high temperatures. When exposed to high-power continuous light energy or high-pulse reflected light, the fiber bundles often decompose or break after a period of use. Therefore, a fiber bundle connector capable of withstanding high-power or high-pulse UV light is needed. Furthermore, post-processing to enrich the fiber core and cladding with hydrogen ions can reduce UV light transmission attenuation and extend the fiber's lifespan.

[0003] Currently available ultraviolet fiber bundles on the market mainly use inorganic or organic adhesives to connect optical fibers into fiber bundles of the required shape and type. Since the ultraviolet light source at the light source end is a laser source with good coherence, its pulse center energy value is very high, generally in the range of kilojoules to tens of thousands of joules. Its output spectrum is very narrow, so high-purity fluorine-doped silicon core optical fibers are required as transmission conductors. Because its total output power is relatively low, multiple ultraviolet fiber bundles need to be bundled and transmitted in parallel. At the other end of the fiber bundle, a circular or square output end is used to output the desired square or circular light spot. This output end is similar to an aperture stop, which can shape and limit the output optical path, so that the fiber bundle outputs a desired circular or square light spot.

[0004] Meanwhile, after the fiber bundle is bonded, due to its long-term use, the high-power light energy will cause a large number of photons to wear on the end face due to long-term scattering and reflection at the end face. Some of the high-power laser is reflected back to the bonded point of the fiber bundle, which will cause cracks and damage to the fiber bundle. Summary of the Invention

[0005] The purpose of this invention is to provide an ultraviolet beam device with high transmission power, high temperature resistance, and low attenuation characteristics, and its preparation method.

[0006] The high-temperature resistant, low-attenuation ultraviolet fiber bundle device provided by this invention consists of multiple ultraviolet fibers arranged in a sequential, tightly packed manner and bound within an outer hollow capillary tube. The multiple ultraviolet fibers are inserted into the hollow capillary tube, and the capillary tube is thermally fused and tapered, so that the multiple ultraviolet fibers are bound within the tapered capillary tube to form a tightly packed ultraviolet fiber bundle. Then, the ultraviolet fiber bundle is subjected to high-pressure hydrogen loading treatment to form a low-attenuation ultraviolet fiber bundle device.

[0007] Specifically, the low-attenuation ultraviolet fiber bundle device provided by the present invention is obtained by the following preparation method:

[0008] (1) Prepare multiple ultraviolet optical fibers, strip the coating layer of the ultraviolet optical fibers to obtain clean bare ultraviolet optical fibers for later use;

[0009] (2) Insert multiple bare ultraviolet optical fibers into a hollow capillary tube in sequence and arrange them in an orderly manner;

[0010] (3) The capillary containing multiple ultraviolet optical fibers is placed in an optical fiber fusion tapering machine. The capillary and the ultraviolet optical fibers piled inside the tube are heated for a short time (e.g., 20-30 seconds) using an oxyhydrogen flame, which is used to perform high-temperature thermal fusion, causing the heated part to become vitrified. The head part of the ultraviolet optical fiber bundle is melted and synthesized into a bundle of ultraviolet optical fibers. The temperature of the oxyhydrogen flame here is generally 2500-3000 degrees, which can directly thermally fuse the capillary and optical fibers.

[0011] Similarly, if an oxyhydrogen flame is used for prolonged heating (e.g., 50-60 seconds), i.e., thermal fusion tapering is performed, the heated part is completely vitrified, the diameter of the fiber bundle becomes smaller, and it becomes tapered; after thermal fusion tapering, a smaller ultraviolet fiber bundle is obtained tightly bound in a capillary.

[0012] (4) The obtained ultraviolet fiber bundle is subjected to high-pressure hydrogen loading treatment to replenish the hydrogen ion content in the ultraviolet fiber and reduce attenuation.

[0013] In this invention, the high-pressure hydrogen loading treatment of the ultraviolet fiber bundle includes the following steps:

[0014] (1) In order to better enable ultraviolet optical fibers to be repaired and optimized by carrying hydrogen ions, the ultraviolet optical fiber bundle after high-temperature thermal fusion or thermal fusion tapering can be subjected to low-dose pre-radiation treatment in a closed space through an ionizing radiation source, such as gamma rays; the dose is generally 10. 4 Gray to 2×10 4 Between Gray;

[0015] (2) The pre-radiated ultraviolet fiber bundle is sent into a high-pressure hydrogen chamber at 100-120 Bar;

[0016] (3) The ultraviolet fiber bundle is stored in a high-pressure hydrogen chamber for 20-30 days to repair the silicon-oxygen bonds of the fiber damaged by radiation with hydrogen ions.

[0017] After the ultraviolet fiber bundle was removed, an attenuation test was conducted under an ultraviolet light source. The fiber bundle treated with hydrogen was then usable.

[0018] In this invention, the hollow capillary is a circular capillary, and the light spot emitted after multiple ultraviolet optical fibers are bundled together is a circular light spot.

[0019] In this invention, the hollow capillary is a square capillary, and the light spot emitted after multiple ultraviolet optical fibers are bundled together is a square light spot.

[0020] In this invention, the outer diameter of each ultraviolet fiber in the ultraviolet fiber bundle does not change after thermal fusion tapering, and the ultraviolet fiber bundle emits light uniformly.

[0021] In this invention, each ultraviolet optical fiber has a diameter of 120-140 μm; the hollow capillary has an inner diameter of 900 μm, an outer diameter of 1000 μm, and a length of 100-200 mm.

[0022] In this invention, after the ultraviolet fiber bundle is thermally tapered and bundled, the diameter of each ultraviolet fiber is reduced from 120-140um to 30-50um, and the fiber bundle emits light uniformly.

[0023] In this invention, the ultraviolet fiber bundle after thermal fusion is subjected to high-pressure hydrogen loading treatment, which involves radiation pretreatment of the ultraviolet fiber bundle and high-pressure hydrogen loading repair to reduce the attenuation of the ultraviolet fiber bundle.

[0024] This invention addresses the aforementioned problems that arise when ultraviolet light beams are bonded together. It employs a thermal fusion bonding method for silica ultraviolet optical fibers, resulting in a tighter bond between the fibers within the fiber bundle. This allows the fiber bundle to withstand high-temperature pulse energy and prolonged application in LDI exposure, significantly extending its lifespan. Furthermore, the fiber ends can be tapered to reduce the diameter of both the fiber bundle and the individual fibers, achieving a diameter range of 30µm for silica optical fibers. This enables more precise operations in the future ultraviolet light beam field.

[0025] Finally, the device undergoes hydrogenation treatment, which involves placing the fiber bundle into a pressurized hydrogen chamber to effectively add hydrogen ions. These hydrogen ions are generated under long-term ultraviolet radiation or high-energy pulsed ultraviolet radiation.

[0026] (1) SiH fission transforms into E' color centers;

[0027] (2) The stretched SiO bond cracks produce NBOH (265 nm) and E' (215 nm) absorption bands;

[0028] (3) As optical fibers degrade over a long period of use, the amount of light transmission attenuation increases.

[0029] This invention repairs ultraviolet fiber loss caused during thermal fusion in this way, ensuring that such fibers can be used for a longer period of time and extending the life of fiber bundles and equipment. After the fiber bundle is bundled, it is subjected to hydrogen loading treatment. After high-pressure hydrogen loading of the ultraviolet fiber through a sealed hydrogen loading chamber, the hydrogen ions lost in each fiber of the fiber bundle during melting, bundling, and becoming a device are well recovered. This repairs E' color center defects and non-bridging oxygen hole center defects, and greatly reduces the energy attenuation of the light source in the short-wavelength band. Attached Figure Description

[0030] Figure 1 This is a cross-sectional view of the first type of optical fiber bundle (circular) of the present invention.

[0031] Figure 2 This is a cross-sectional view of the second type of optical fiber bundle (rectangular) of the present invention.

[0032] Figure 3 for Figure 1 A cross-sectional view of the fiber bundle after thermal fusion tapering, reduced to a fiber with a diameter of 50 μm.

[0033] Figure 4 for Figure 1 After the circular optical fibers are bundled together, they are heat-fused but not tapered. Side views before (a) and after (b) heat-fused.

[0034] Figure 5 for Figure 2 After the square optical fibers are bundled together, they are heat-fused but not tapered. Side views before (a) and after (b) heat-fused.

[0035] Figure 6 For the present invention Figure 3 Side views of the fiber bundle before (a) and after (b) thermal tapering and bonding.

[0036] Figure 7 To enter the high-pressure hydrogen chamber and resume the hydrogen ion preparation process. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0038] The low-attenuation ultraviolet fiber bundle device provided by this invention is shown in the appendix. Figure 1 , 2 .

[0039] First, the obtained bare optical fibers are arranged in a neat hexagonal or rectangular pattern. In this embodiment, a fluorine-doped multimode ultraviolet silica optical fiber with a core diameter of 105 μm and a cladding diameter of 125 μm is used.

[0040] In Example 1, the above-mentioned fluorine-doped multimode ultraviolet silica optical fibers (1.1) are arranged in a circular pattern. The core layer consists of one fiber, the second fiber ring consists of six fibers of the same specification, and the outer layer consists of twelve fibers of the same specification. These fibers are manually arranged neatly and then inserted into a capillary tube. The capillary tube is generally a special silica capillary tube, including a circular capillary tube (1.2). The circular capillary tube (1.2) has an inner diameter of 900 μm, an outer diameter of 1000 μm, and a length of 100-200 mm. After the fiber bundle is subjected to high-temperature fusion splicing with an oxyhydrogen flame for 20-30 seconds on a fusion splicer, the fiber bundle is tightly fixed and arranged together without significantly changing the fiber diameter. Figure 4 As shown, (a) shows the state of the optical fiber bundle before thermal fusion. Figure 4 In the thermally fused bundle section (4.1), after the bundle is combined, the right fiber bundle (b) collapses slightly. The fibers inside the capillary are more tightly bound together due to the melting of the fluorine-doped outer wall. The capillary diameter shrinks, and the diameter of the fiber bundle (b) shrinks by about 100um. After the bundle is combined, a bundle device with a length of about 100-200mm is formed. Its output light spot is a uniform circular light spot. Measured with an oscilloscope, it can be basically confirmed that it is a circular flat-top light with the same light intensity.

[0041] Example 2: If a rectangular light spot is required at the output end, a corresponding rectangular quartz capillary tube is used, such as... Figure 2 .

[0042] A rectangular ultraviolet fiber bundle typically consists of 5 rows of staggered fiber optic cables, with 10-20 cables in each row. Figure 2 As shown, this embodiment uses a square ultraviolet fiber combiner with 15 fluorine-doped multimode ultraviolet quartz fibers per row (2.1), totaling 75 fibers. These fibers are similarly threaded into a capillary tube (2.2), which is also a specially made square quartz tube with an inner diameter of 2600 μm and an outer diameter of 2800-2900 μm. After the fiber bundle is heat-fused together by a hydrogen-oxygen flame for 20-30 seconds, the fiber bundle is tightly fixed and arranged together without significantly altering its diameter. Figure 5 As shown, the state of the fiber bundle before thermal fusion is shown on the left (a). After thermal fusion (5.1), the fiber bundle on the right (b) shows a slight collapse. The fibers inside the capillary are more tightly bound together due to the melting of the fluorine-doped outer wall, and the capillary diameter shrinks, while the outer diameter of the fiber bundle remains rectangular. After thermal fusion, a bundle device with a length of approximately 100-200 mm is formed, and its output light spot is a uniform square spot. Its light intensity output mainly consists of five long linear spots with uniform light intensity. Measured with an oscilloscope, it can be basically determined that these are rectangular spots with similar light intensity.

[0043] Example 3: If it is necessary to perform thermoforming tapering to reduce the size of the fiber bundle, such as... Figure 3 As shown, a fluorine-doped multimode ultraviolet silica fiber (3.1) with a cladding diameter of 125 μm is required. The inner diameter of the fiber bundle mold of the circular capillary (3.2) is 1000 μm. In order to make the output light spot of the output side smaller after bundle bonding, the fiber bundle can be subjected to hydrogen-oxygen flame thermal fusion tapering for a longer period of about 50-60 seconds. After the fiber bundle is rotated, the end diameter will shrink. The fiber bundle has a thermally fused part (6.1). After tapering, the diameter of the fiber bundle can be reduced from 1000 μm to about 240 μm. Figure 6 As shown in (b). After tapering, the optical fibers are basically evenly arranged. However, due to their hexagonal arrangement, and during the high-temperature oxyhydrogen flame drawing process, the fluorine-doped silicon oxide on the surface of each optical fiber, with its relatively low melting point, will gradually accumulate into an imperfect near-hexagonal shape, such as... Figure 3 As shown.

[0044] The method for fabricating a low-attenuation ultraviolet fiber bundle device provided by the present invention includes the following steps:

[0045] (1) Prepare multiple ultraviolet optical fibers, strip the coating layer of the ultraviolet optical fibers to obtain clean bare ultraviolet optical fibers for later use.

[0046] (2) Insert multiple bare ultraviolet optical fibers into a hollow capillary tube in sequence and stack them up;

[0047] (3) The capillary containing multiple ultraviolet optical fibers is thermally fused and tapered to obtain an ultraviolet optical fiber bundle tightly bound in the capillary.

[0048] (4) The obtained ultraviolet fiber bundle is subjected to high-pressure hydrogen loading treatment to replenish the hydrogen ion content in the ultraviolet fiber and reduce attenuation.

[0049] Meanwhile, according to CN112379477 A (A self-pressurized optical fiber hydrogen-carrying system and its method), it is known that placing ordinary optical fiber into a self-pressurized hydrogen-carrying system is a common operation in the special optical fiber industry for processing ultraviolet optical fiber devices. Placing ultraviolet optical fiber into a hydrogen chamber for hydrogen loading can reduce the loss of optical fiber during transmission.

[0050] The hydrogenation treatment of ultraviolet light beams consists of four steps, such as... Figure 7 As shown.

[0051] (7.1) The fiber bundle device prepared above is placed in a closed space for pre-irradiation, and the dose is adjusted from 10 to 10 using a γ-ray ionizing radiation source. 4 Gray to 2×10 4 After being exposed to radiation between the gray areas for approximately 24-72 hours, the contents were immediately removed and placed in the high-pressure hydrogen chamber described below.

[0052] (7.2) Place the fiber bundle in a stable high-pressure hydrogen chamber at a pressure of 100-120 atmospheres.

[0053] (7.3) Place the fiber bundle in a high-pressure hydrogen chamber for about 20-30 days at room temperature.

[0054] (7.4) After the fiber bundle is removed and left for 7 days, an attenuation test is performed on the fiber bundle.

[0055] Untreated fiber bundles and fiber bundles that have undergone pre-radiation and hydrogen loading treatment were tested for radiation doses of 30 Gy, 100 Gy, 1000 Gy, and 10000 Gy, respectively. Then, they were connected to a 350 nm light source. It was found that the attenuation of the treated fiber bundle increased to about 5% of that of the untreated fiber bundle.

[0056] The fiber optic test results show that the hydrogen-treated ultraviolet (UV) beam significantly improves the UV radiation attenuation and can be used for extended periods in low-to-medium power continuous UV environments. Nine months after treatment, tests were conducted on UV beams that had undergone pre-radiation and hydrogen loading, as well as those that had not. The results showed that the untreated UV beam had an intensity of only 30% of its original value under radiation, while the pre-radiated and hydrogen-loaded fiber beam had an intensity of approximately 80% of its initial value.

Claims

1. A method of making a low-loss ultraviolet fiber-bundle device, comprising: The specific steps are: (1) Prepare multiple UV fibers, remove the coating layer of the UV fibers to obtain clean UV fiber bare fibers; (2) Insert the multiple UV fiber bare fibers into the hollow capillary in turn for ordered stacking arrangement; the diameter of each UV fiber is 120-140 um; (3) Put the capillary containing multiple UV fibers into a fiber fusion tapering machine, use a hydrogen-oxygen flame for short-time heating of 20-30 seconds, i.e. high-temperature heating of 2500-3000°C, to make the heated part vitrify, the head part of the UV fiber bundle melt, and synthesize a UV fiber bundle; after the heat fusion tapering, the outer diameter of each UV fiber in the UV fiber bundle does not change, and the UV fiber bundle emits light uniformly; or put the capillary containing multiple UV fibers into a fiber fusion tapering machine, use a hydrogen-oxygen flame for long-time heating of 50-60 seconds, i.e. heat fusion tapering, which makes the heated part completely vitrify, the diameter of the fiber bundle becomes smaller and becomes conical; after heat fusion tapering, a reduced UV fiber bundle is obtained which is tightly bound in the capillary; after heat fusion tapering and bundling, the diameter of each UV fiber in the UV fiber bundle is reduced from 120-140 um to 30-50 um, and the fiber bundle emits light uniformly; (4) Perform high-pressure hydrogen loading treatment on the obtained UV fiber bundle to supplement the content of hydrogen ions in the UV fiber and reduce attenuation; the specific steps are: (1) The UV fiber bundle after high temperature hot melting or hot melting and tapering in a closed space is irradiated by an ionizing radiation source for 10 4 Gy to 2 x 10 4 Gy of low dose pre-irradiation treatment; (2) Send the pre-irradiated UV fiber bundle into a high-pressure hydrogen chamber of 100-120 Bar; (3) Store the UV fiber bundle in the high-pressure hydrogen chamber for 20-30 days; repair the silicon-oxygen bond of the damaged fiber in the radiation with hydrogen ions.

2. The production method according to claim 1, characterized by, The hollow capillary is a round capillary, and the light spot of the bundled multiple UV fibers is a round spot.

3. The preparation method according to claim 1, characterized in that, The hollow capillary is a square capillary, and the light spot of the bundled multiple UV fibers is a square spot.

4. A low-attenuation UV fiber bundle device prepared by the preparation method of any one of claims 1-3.

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