Photonic crystal fiber and single-mode hollow fiber air cavity end face plugging method

Abstract

The invention provides a photonic crystal fiber and single-mode hollow fiber air cavity end face plugging method, which comprises the following steps: sucking photosensitive glue into air holes at two ends of a fiber by utilizing the cold and hot change of air in the air holes of the fiber and the reduction of pressure in the cooled sealed air holes of the fiber, and then curing the photosensitive glue to plug the air holes. The method is suitable for industrial production, and comprises the following steps: a, heating an optical fiber, b, immersing two ends of the optical fiber below a photosensitive glue liquid level in a photosensitive glue tank, cooling the optical fiber to cool and depressurize air in air holes in the optical fiber, and sucking the photosensitive glue into the air holes at two ends of the optical fiber, c, taking the optical fiber adsorbing the photosensitive glue out of the photosensitive glue tank, irradiating two ends of the optical fiber with ultraviolet light, and curing the photosensitive adhesive in air holes at two ends of the optical fiber.

Description

Technical Field

[0001] This invention relates to molecular crystal optical fibers and hollow optical fibers, specifically, to a method for sealing the air cavity end face of photonic crystal optical fibers and single-mode hollow optical fibers. Background Technology

[0002] CN103278883A discloses a technique for selectively filling photonic crystal fibers. This method involves micromanipulating polystyrene microspheres to a specific location above an air hole in the photonic crystal fiber. The polystyrene microspheres are then melted at high temperature to seal the air hole. Next, molten wax oil is introduced through capillary action into the remaining open and closed air holes of the photonic crystal fiber, with the wavefront higher than the location of the molten microspheres used for sealing. Finally, a section submerged in wax oil is retained, resulting in a photonic crystal fiber with an open and closed air hole at a specific location on one end, and a closed air hole on the remaining end. CN114815039A relates to a method for fabricating an optical fiber fluid channel, comprising the following steps: Step 1, fabricating a fluid channel port at one end of a microstructured optical fiber using a selective filling method based on polystyrene microspheres and paraffin oil; Step 2, with air supplied to one end of the microstructured optical fiber, sealing the other end of the optical fiber except for the port corresponding to the fluid channel using UV-curable adhesive, thus fabricating the other end of the fluid channel. Following the treatment of one end of the optical fiber with a combination of polystyrene microspheres and paraffin oil, the optical fiber is connected to a syringe needle using paraffin oil, and air is slowly injected into the optical fiber while the other end of the optical fiber is immersed in a low-viscosity UV-curable adhesive. Subsequently, irradiation with a UV lamp allows the opening and closing of pores at the same location as the other end, while the remaining pores are closed, thereby completing the fabrication of the fluid channel within the optical fiber. CN106019482A discloses a method for fusion splicing a photonic crystal fiber and a single-mode fiber. First, a photocuring agent is impregnated into the first end of the photonic crystal fiber. Then, ultraviolet light is coupled from the second end of the photonic crystal fiber into its core, causing the photocuring agent around the core in the first end to cure and fill the air holes in the photonic crystal fiber. Next, the uncured photocuring agent in the first end is removed, and the second end of the photonic crystal fiber is sealed. Air pressure is applied to the first end of the photonic crystal fiber, making the air pressure in the unfilled air holes higher than atmospheric pressure. Simultaneously, the first end of the photonic crystal fiber is discharged and heated to 1400℃-1900℃, causing the unfilled air holes in the first end to collapse and close. Finally, the first end of the photonic crystal fiber is fused with the single-mode fiber.

[0003] The above methods are complex to operate, suitable only for laboratory use, and difficult to promote and apply. Moreover, some of them can only be sealed with photosensitive adhesives with low viscosity.

[0004] The sealing of pores at both ends of hollow optical fibers faces the same problem as that of photonic crystal fibers, especially for single-mode hollow optical fibers. Summary of the Invention

[0005] The purpose of this invention is to provide a method for sealing the air cavity end faces of photonic crystal fibers and single-mode hollow fibers. It utilizes the temperature changes of the air inside the fiber pores. After cooling, the pressure inside the sealed fiber pores decreases, drawing photosensitive adhesive into the pores at both ends of the fiber. Then, the photosensitive adhesive is cured to seal the pores. This method is convenient to operate, highly efficient, and suitable for industrial production.

[0006] A method for sealing the air cavity end faces of photonic crystal fibers and single-mode hollow fibers includes the following steps: a) heating the optical fiber; b) immersing both ends of the optical fiber below the surface of the photosensitive adhesive in a photosensitive adhesive tank, cooling the optical fiber, thereby reducing the temperature and pressure of the air in the pores of the optical fiber, and drawing the photosensitive adhesive into the pores at both ends of the optical fiber; c) removing the optical fiber with the adsorbed photosensitive adhesive from the photosensitive adhesive tank, and irradiating both ends of the optical fiber with ultraviolet light to solidify the photosensitive adhesive in the pores at both ends of the optical fiber.

[0007] As an improvement, step b is as follows: the lower ends of the optical fiber bent into an n-shape are immersed below the surface of the photosensitive adhesive in the photosensitive adhesive tank, and the upper part of the n-shaped optical fiber extends into the cooling chamber of the cooler. The cooler cools the optical fiber, and the air in the pores of the optical fiber is cooled and depressurized. The photosensitive adhesive is drawn into the pores at both ends of the optical fiber.

[0008] As an improvement, the lower part of the n-shaped optical fiber is positioned on a flexible sealing plate, and the cooling chamber of the cooler has an opening on the bottom surface that matches the sealing plate. The sealing plate and the opening are plugged in.

[0009] Step b is as follows: Insert the sealing plate into the cooling chamber opening of the cooler, and extend the upper part of the n-shaped optical fiber into the cooling chamber; move the cooler and the sealing plate together so that the two ends of the optical fiber outside the cooling chamber are immersed below the surface of the photosensitive adhesive in the photosensitive adhesive tank, the cooler cools the optical fiber, the air in the pores of the optical fiber is cooled and depressurized, and the photosensitive adhesive is drawn into the pores at both ends of the optical fiber; move the cooler and the sealing plate together to the outside of the photosensitive adhesive tank.

[0010] As an improvement, a heater is used to heat the optical fiber. The heating chamber of the heater has an opening on the bottom surface that matches the sealing plate. The sealing plate and the opening are plugged in.

[0011] Step a specifically involves: positioning the lower part of the n-shaped optical fiber on the sealing plate, inserting the sealing plate into the heating chamber opening of the heater, and extending the upper part of the n-shaped optical fiber into the heating chamber; heating the optical fiber with the heater; and pulling the sealing plate out of the heater opening.

[0012] As an improvement, two perforations are made on the sealing plate for optical fibers to pass through, and there is a cut between the inner wall of the perforations and the outer wall of the sealing plate to cut the sealing plate.

[0013] As an improvement, the following steps are added after step c: d, remove the protective layer at both ends of the optical fiber to expose the fiber core; e, glue the ceramic head to the outer periphery of the fiber core and part of the protective layer; f, polish the ends of the ceramic head and the fiber core.

[0014] The fiber optic pore sealing device used in the method of sealing the air cavity end face of photonic crystal fiber and single-mode hollow fiber includes a photosensitive adhesive tank containing photosensitive adhesive, a cooler for cooling the fiber, and an ultraviolet light source; the cooler has a cooling cavity, and the cooling cavity of the cooler has an opening on the bottom surface that matches the sealing plate, and the sealing plate and the opening are plugged in; the lower part of the n-shaped fiber is positioned on the sealing plate.

[0015] As an improvement, at least one inner wall of the cooling cavity is a cold end substrate of a semiconductor cooler.

[0016] As an improvement, both opposing inner walls of the cooling cavity are cold end substrates of a semiconductor cooler.

[0017] As an improvement, a heater for heating the optical fiber is also included, wherein the heating chamber of the heater has an opening on the bottom surface that matches the sealing plate, and the sealing plate and the opening are plug-in connected.

[0018] As an improvement, at least one inner wall of the heating cavity is a hot-end substrate of a semiconductor cooler.

[0019] As an improvement, two perforations are made on the sealing plate for optical fibers to pass through.

[0020] As an improvement, there is a cut between the inner wall of the perforation and the outer wall of the sealing plate to cut the sealing plate.

[0021] The beneficial effects of this invention are:

[0022] After the optical fiber (photonic crystal fiber or single-mode hollow fiber) is heated, the air inside the pores expands due to heat, reducing its density and pressure. The heated ends of the fiber are then inserted below the surface of a photosensitive adhesive liquid. Cooling the fiber causes the air inside the pores to cool and depressurize, drawing the photosensitive adhesive into the pores at both ends of the fiber. Ultraviolet light is then applied to both ends of the fiber, causing the photosensitive adhesive in the pores to solidify and seal the pores. The height of the photosensitive adhesive in the pores at both ends of the fiber can be controlled and adjusted according to the temperature difference between the heated and cooled fiber. This method is convenient to operate, highly efficient, and has high production efficiency. This invention has no special requirements on the viscosity of the photosensitive adhesive and has wide applicability.

[0023] To facilitate operation, the heated optical fiber is bent into an n-shape and positioned on a sealing plate made of a flexible material (such as a foam board). The sealing plate is inserted into the cooling chamber opening of the cooler, and the upper part of the n-shaped optical fiber extends into the cooling chamber. The cooler then operates to cool the optical fiber, resulting in higher cooling efficiency. Furthermore, the sealing plate's seal on the cooling chamber opening enhances the cooling effect.

[0024] The cuts on the sealing plate make it easier to insert or remove optical fibers from the perforations without damaging them.

[0025] Alternatively, an open heater can be used to heat the optical fiber, with the sealing plate sealing the opening for faster heating. After heating, the sealing plate with the heated optical fiber can be removed from the heater and inserted into the opening of the cooler for cooling, further improving operational efficiency.

[0026] For future applications of optical fibers, after sealing the air holes, the protective layer at both ends of the optical fiber can be removed, and then ceramic heads can be glued on. The ends of the ceramic heads and the fiber core can then be polished. This is an existing technology.

[0027] The structure of coolers and heaters based on semiconductor coolers is simpler. Semiconductor coolers are existing technology; they are chips made using the Peltier effect of semiconductor materials that can generate cooling or heating. They have opposing cold-end and hot-end substrates. When the semiconductor cooler is powered on, one end of the substrate emits cooling energy; this end is the cold-end substrate. The other end of the substrate emits heat; this end is the hot-end substrate. The semiconductor cooler can be the one disclosed in CN103697618B or the semiconductor cooler chip disclosed in CN222216359U. Of course, at least one inner wall of the cooling chamber of the cooler is the cold-end substrate of the semiconductor cooler, and at least one inner wall of the heating chamber of the heater is the hot-end substrate of the semiconductor cooler. Attached Figure Description

[0028] Figure 1 This is a front view of the heater, sealing plate, optical fiber, etc.

[0029] Figure 2 yes Figure 1 Top view.

[0030] Figure 3 This is a front view of the cooler, sealing plate, optical fiber, etc.

[0031] Figure 4 yes Figure 2 Top view.

[0032] Figure 5 This is a schematic diagram of the UV curing process.

[0033] Figure 6 This is a schematic diagram of an optical fiber with the protective layer at the end removed.

[0034] Figure 7 This is a schematic diagram of the fiber optic end after a ceramic connector has been glued to it.

[0035] In the diagram, heater 1, heating chamber 11,

[0036] Cooler 2, refrigeration chamber 21, inner wall of refrigeration chamber 22,

[0037] Sealing plate 3, perforation 31, cut 32

[0038] 4. Photosensitive adhesive tank; 5. Ultraviolet light source.

[0039] Semiconductor cooler 6, cold end substrate 61, hot end substrate 62, semiconductor particles 63

[0040] Fiber 7, pores 71, protective layer 72

[0041] 8. Photosensitive adhesive; 9. Ceramic head. Detailed Implementation

[0042] Example 1: Method for Sealing the Air Cavity End Face of Photonic Crystal Fiber

[0043] The method for sealing the air cavity end face of a photonic crystal fiber is as follows: a) Heat the optical fiber; b) Immerse both ends of the optical fiber below the surface of the photosensitive adhesive in a photosensitive adhesive tank, cool the optical fiber, and reduce the temperature and pressure of the air in the pores of the optical fiber, so that the photosensitive adhesive is drawn into the pores at both ends of the optical fiber; c) Remove the optical fiber with the adsorbed photosensitive adhesive from the photosensitive adhesive tank, and irradiate both ends of the optical fiber with ultraviolet light to solidify the photosensitive adhesive in the pores at both ends of the optical fiber.

[0044] The device for sealing pores in optical fibers includes a heater 1 for heating the optical fiber, a cooler 2 for cooling the optical fiber, a sealing plate 3 made of flexible material, a photosensitive adhesive tank 4 containing photosensitive adhesive, and an ultraviolet light source 5.

[0045] See Figure 3 , 4 The cooler 2 has a cubic refrigeration chamber 21, the bottom surface of which is an opening that matches the sealing plate 3. The sealing plate and the opening are connected by a plug-in seal.

[0046] The two relatively large inner walls 22 of the cooling chamber 21 are both cold-end substrates 61 of the semiconductor cooler 6. The hot-end substrate 62 of the semiconductor cooler 6 is opposite to the cold-end substrate 61 and is disposed at the other end away from the cold-end substrate 61. Semiconductor particles 63 are located between the hot-end substrate 62 and the cold-end substrate 61.

[0047] See Figure 1 , 2 The heater 1 and the cooler 2 have similar structures. The bottom surface of the heating chamber 11 of the heater 1 has an opening that matches the sealing plate. The sealing plate and the opening are plugged in. The two relatively large inner walls of the heating chamber 11 are the hot end substrate 62 of the semiconductor cooler 6.

[0048] The sealing plate 3 has two through holes 31 for the optical fiber 7 to pass through; there is a cut 32 between the inner wall of the through holes and the outer wall of the sealing plate to cut the sealing plate so that the optical fiber 7 can enter and exit the through holes 31.

[0049] The method for sealing the air cavity end face of a photonic crystal fiber includes the following steps.

[0050] Step a: See Figure 1 , 2 The optical fiber 7, bent into an n-shape, is inserted into the perforation 31 of the sealing plate through the cut of the sealing plate 3. The optical fiber is positioned on the sealing plate. The sealing plate 3 is inserted into the opening of the heating chamber of the heater 1, and the upper part of the n-shaped optical fiber extends into the heating chamber 11. After the heater heats the optical fiber, the sealing plate 3 with the optical fiber is pulled out from the opening of the heater.

[0051] Step b: See Figure 3 , 4 Insert the sealing plate 3 into the cooling chamber opening of the cooler 2, and extend the upper part of the n-shaped optical fiber into the cooling chamber; move the cooler and the sealing plate together so that the two ends of the optical fiber outside the cooling chamber are immersed below the liquid surface of the photosensitive adhesive 8 in the photosensitive adhesive tank 4. The cooler 2 cools the optical fiber 7, and the air in the pores 71 of the optical fiber 7 is cooled and depressurized. The photosensitive adhesive 8 is drawn into the pores at both ends of the optical fiber; then, move the cooler and the sealing plate with the optical fiber together to the outside of the photosensitive adhesive tank.

[0052] Step c: See Figure 5 The optical fiber is irradiated with ultraviolet light source 5 to cure the photosensitive adhesive 8 in the pores at both ends of the optical fiber; the optical fiber is then removed from the sealing plate 3.

[0053] Step d: See Figure 6 Remove the protective layer 72 at both ends of the optical fiber 7 to expose the fiber core.

[0054] Step e: See Figure 7 The ceramic head 9 is bonded to the outer periphery of the fiber core and part of the protective layer.

[0055] Step f: Polish the ends of the ceramic head and the fiber core.

[0056] Example 2: Method for Sealing the Air Cavity End Face of Single-Mode Hollow Fiber

[0057] Example 2 is basically the same as Example 1, except that the photonic crystal fiber in Example 1 is replaced with a single-mode hollow fiber.

[0058] The scope of protection of this patent includes, but is not limited to, the above-described embodiments. The scope of protection of this patent is determined by the claims. Any substitutions, modifications, or improvements to this technology that are easily conceived by those skilled in the art shall fall within the scope of protection of this patent.

Claims

1. A method for sealing the air cavity end face of photonic crystal fiber and single-mode hollow fiber, characterized in that: The steps include: a) heating the optical fiber; b) immersing both ends of the optical fiber below the surface of the photosensitive adhesive in the photosensitive adhesive tank, cooling the optical fiber, causing the air in the pores of the optical fiber to cool and depressurize, and the photosensitive adhesive to be drawn into the pores at both ends of the optical fiber; c) removing the optical fiber with the adsorbed photosensitive adhesive from the photosensitive adhesive tank, and irradiating both ends of the optical fiber with ultraviolet light, so that the photosensitive adhesive in the pores at both ends of the optical fiber is cured.

2. The method for sealing the air cavity end face of photonic crystal fiber and single-mode hollow fiber as described in claim 1, characterized in that: Step b specifically involves immersing the lower ends of the n-shaped optical fiber below the surface of the photosensitive adhesive in the photosensitive adhesive tank, while the upper part of the n-shaped optical fiber extends into the cooling chamber of the cooler. The cooler cools the optical fiber, causing the air in the pores of the optical fiber to cool down and depressurize. The photosensitive adhesive is then drawn into the pores at both ends of the optical fiber.

3. The method for sealing the air cavity end face of photonic crystal fiber and single-mode hollow fiber as described in claim 2, characterized in that: The lower part of the n-shaped optical fiber is positioned on a flexible sealing plate. The cooling chamber of the cooler has an opening on the bottom surface that matches the sealing plate. The sealing plate and the opening are plugged in. Step b is as follows: Insert the sealing plate into the cooling chamber opening of the cooler, and extend the upper part of the n-shaped optical fiber into the cooling chamber; move the cooler and the sealing plate together so that the two ends of the optical fiber outside the cooling chamber are immersed below the surface of the photosensitive adhesive in the photosensitive adhesive tank, the cooler cools the optical fiber, the air in the pores of the optical fiber is cooled and depressurized, and the photosensitive adhesive is drawn into the pores at both ends of the optical fiber; move the cooler and the sealing plate together to the outside of the photosensitive adhesive tank.

4. The method for sealing the air cavity end face of photonic crystal fiber and single-mode hollow fiber as described in claim 3, characterized in that: The optical fiber is heated by a heater. The heating chamber of the heater has an opening on the bottom surface that matches the sealing plate. The sealing plate and the opening are plugged in. Step a specifically involves: positioning the lower part of the n-shaped optical fiber on the sealing plate, inserting the sealing plate into the heating chamber opening of the heater, and extending the upper part of the n-shaped optical fiber into the heating chamber; heating the optical fiber with the heater; and pulling the sealing plate out of the heater opening.

5. The method for sealing the air cavity end face of photonic crystal fiber and single-mode hollow fiber as described in claim 3, characterized in that: The sealing plate has two perforations for optical fibers to pass through, and there is a cut between the inner wall of the perforations and the outer wall of the sealing plate to cut the sealing plate.

6. The method for sealing the air cavity end face of photonic crystal fiber and single-mode hollow fiber as described in any one of claims 1-5, characterized in that: After step c, the following steps are added: d, remove the protective layer at both ends of the optical fiber to expose the fiber core; e, glue the ceramic head to the outer periphery of the fiber core and part of the protective layer; f, polish the ends of the ceramic head and the fiber core.

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