Carbon coating optical fiber containing compact carbon layer

Abstract

The utility model provides a carbon coating optical fiber containing a compact carbon layer, which relates to the technical field of optical fibers, and is characterized in that an optical fiber core rod is arranged in an outer structure cladding, and an air layer is formed between the inner wall of the outer structure cladding and the outer wall of the optical fiber core rod; and at least one carbon coating is formed between the air layer and the outer wall of the optical fiber core rod and / or between the inner wall of the outer structure cladding and the air layer. The device has the beneficial effects that the effect of preventing mechanical damage is enhanced; and the carbon element of the carbon coating does not pollute the external coating layer.

Description

Technical Field

[0001] This utility model relates to the field of optical fiber technology, and in particular to a carbon-coated optical fiber containing a dense carbon layer. Background Technology

[0002] In harsh environments, such as submarine optical cables, marine exploration systems, and oil exploration, the original coatings of optical fibers, composed of silicone rubber, polyurethane, or acrylate, while protecting the fiber, cannot prevent the effects of moisture and hydrogen on its mechanical strength and optical performance. This significantly shortens the service life of ordinary optical fibers under humid or small bending radius conditions. Optical fibers with a carbon film coated on their surface are called carbon-coated fibers (CCF). The mechanism involves using a dense carbon film to isolate the fiber surface from the external environment, thereby improving mechanical fatigue loss and reducing hydrogen molecule loss. CCF is a type of hermetically sealed coated fiber (HCF).

[0003] Carbon-sealed coated optical fiber, or simply carbon-coated fiber, is produced by forming a nanometer-thick carbon film on the surface of a quartz clad fiber during the drawing process. Despite its thinness, the carbon film has a dense structure, effectively blocking moisture and hydrogen, exhibiting minimal shrinkage on the fiber surface, stable chemical properties, and effectively preventing the propagation of microcracks on the fiber surface, thus slowing down the fatigue process of mechanical strength and reducing the density of the carbon film.

[0004] Traditional carbon coating processes involve coating carbon onto the outer surface of optical fibers to protect them. However, the carbon coating itself is thin and brittle, offering limited protection against mechanical damage. Therefore, an additional polymer layer is applied to form an external coating. However, this leads to direct contact between the external coating and the carbon coating, contaminating the coating system. Utility Model Content

[0005] To address the problems existing in the prior art, this utility model provides a carbon-coated optical fiber containing a dense carbon layer, comprising:

[0006] An outer cladding structure, wherein an optical fiber core is provided in the outer cladding structure, and an air layer is formed between the inner wall of the outer cladding structure and the outer wall of the optical fiber core.

[0007] At least one carbon coating is formed between the air layer and the outer wall of the optical fiber core, and / or between the inner wall of the outer cladding and the air layer.

[0008] Preferably, a support tube, support rod, or support arm is provided between the inner wall of the outer cladding and the outer wall of the optical fiber core, so that an air-filled gap is formed between the inner wall of the outer cladding and the outer wall of the optical fiber core, thereby forming the air layer.

[0009] Preferably, the number of the support tube, support rod, or support arm is at least one.

[0010] Preferably, the diameter of the optical fiber core rod is in the range of 5 to 800 micrometers.

[0011] Preferably, the diameter of the outer cladding layer ranges from 15 to 1500 micrometers.

[0012] Preferably, the thickness of the air layer ranges from 1 to 100 micrometers.

[0013] Preferably, the thickness of the carbon coating ranges from 10 to 2000 nanometers.

[0014] Preferably, the fiber core is a fiber waveguide structure.

[0015] Preferably, the optical fiber core rod is made of germanium-doped quartz, fluorine-doped quartz, rare earth-doped quartz, soft glass, or chalcogenide glass.

[0016] The above technical solution has the following advantages or beneficial effects:

[0017] 1. An outer cladding layer is first set outside the optical fiber core, which enhances the protection of the optical fiber from mechanical damage compared to the traditional structure of carbon coating layer plus external coating layer.

[0018] 2. A carbon coating is formed on the inner wall of the outer structural cladding, so that the outer coating layer of the outer structural cladding does not come into direct contact with the carbon coating, and the carbon elements in the carbon coating will not contaminate the coating system of the outer coating layer. Attached Figure Description

[0019] Figure 1 A schematic diagram of a carbon-coated optical fiber containing a dense carbon layer is shown in a preferred embodiment of this utility model.

[0020] Figure 2 This is a schematic diagram of an apparatus for preparing carbon-coated optical fibers in a preferred embodiment of the present invention. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The present invention is not limited to this embodiment; other embodiments that conform to the spirit of the present invention may also fall within its scope.

[0022] In a preferred embodiment of this invention, based on the aforementioned problems existing in the prior art, a carbon-coated optical fiber containing a dense carbon layer is provided, such as... Figure 1 As shown, it includes:

[0023] The outer cladding 1 has an optical fiber core rod 2 inside it, and an air layer 3 is formed between the inner wall of the outer cladding 1 and the outer wall of the optical fiber core rod 2.

[0024] At least one carbon coating 4 is formed between the air layer 3 and the outer wall of the optical fiber core 2, and / or between the inner wall of the outer structural cladding 1 and the air layer 3.

[0025] Specifically, in this embodiment, at least one carbon coating 4 is formed through the fiber structure design, providing stronger protection for the fiber. Furthermore, the carbon coating layer in traditional carbon-coated fibers is thin and brittle, and cannot protect the fiber from mechanical damage. Therefore, a polymer coating is applied on the outside. Standard acrylate coatings can also be used, and polyimide coatings are sometimes used for high-temperature applications. For general manufacturing processes, carbon coatings require high speeds, while polymer coatings require low speeds.

[0026] In this embodiment, an outer cladding layer 1 is first formed outside the optical fiber core 2, and then a carbon coating 4 is formed on the inner wall of the outer cladding layer 1. This ensures that the outer coating layer on the outer wall of the outer cladding layer 1 does not directly contact the carbon coating 4, and the carbon elements in the carbon coating 4 will not contaminate the coating system of the outer coating layer. More types of outer coating layers can be selected, such as polyimide, acrylic resin, silicone, and metals (gold, aluminum, copper, tin, etc.); more coating process methods can be selected, such as thermosetting, photocuring, molten metal coating, magnetron sputtering, etc.

[0027] In a preferred embodiment of the present invention, a support member 5 is provided between the inner wall of the outer cladding 1 and the outer wall of the optical fiber core 2. The support member 5 can be a support tube, a support rod, or a support arm, so that an air-filled gap is formed between the inner wall of the outer cladding 1 and the outer wall of the optical fiber core 2, thereby forming an air layer 3.

[0028] Specifically, in this embodiment, the support tube 5 "suspends" the region of the optical fiber core rod 2 in the center of the outer cladding layer 1 region of the optical fiber, forming an air layer 3.

[0029] In a preferred embodiment of this invention, the number of support tubes, support rods, or support arms is at least one.

[0030] Specifically, in this embodiment, the number of support tubes or support rods can be 1, 2, 3 or more. Since a large number of support tubes will affect the adhesion area of ​​the carbon coating and the hydrogen barrier performance of the carbon coating, a smaller number of support tubes or support rods is preferred.

[0031] The support tube can be replaced with a support wall, and the number of support walls can also be 1, 2, 3 or more.

[0032] In a preferred embodiment of this invention, the diameter of the optical fiber core rod 2 ranges from 5 to 800 micrometers.

[0033] In a preferred embodiment of the present invention, the diameter of the outer structural cladding 1 ranges from 15 to 1500 micrometers.

[0034] In a preferred embodiment of the present invention, the thickness of the air layer 3 ranges from 1 to 100 micrometers.

[0035] In a preferred embodiment of this invention, the thickness of the carbon coating 4 ranges from 10 to 2000 nanometers.

[0036] Specifically, in this embodiment, the dimensions and thicknesses of the fiber core 2, outer cladding 1, air layer 3, and carbon coating 4 are all at the micrometer or nanometer level, ensuring that the diameter of the prepared fiber meets the requirements of most application scenarios.

[0037] In a preferred embodiment of this invention, the optical fiber core rod 2 is an optical fiber waveguide structure.

[0038] Specifically, in this embodiment, the fiber core rod 2 can be not only a solid fiber core rod, but also a communication fiber, active fiber, single-mode fiber, multimode fiber, graded refractive index multimode fiber, large mode area fiber, multi-core fiber, imaging fiber, anti-resonance fiber, and various microstructure fiber structures, including hollow fiber, refractive index light-guiding photonic crystal fiber, large mode area microstructure fiber, etc. The carbon coating fiber internal coating method of this utility model is suitable for all fibers with microstructures and various types of fibers.

[0039] In a preferred embodiment of this invention, the optical fiber core rod 2 is made of germanium-doped quartz, fluorine-doped quartz, rare earth-doped quartz, soft glass, or chalcogenide glass.

[0040] Specifically, such as Figure 2 The apparatus shown in this embodiment is for fabricating carbon-coated optical fibers. The fabrication methods for each layer of the optical fiber can be stacking, extrusion, drilling, etc., which are common industry methods for fabricating microstructured optical fibers. Figure 2 (Not shown in the image) This utility model Figure 2 The main focus is on the process and method of introducing a special gas into the air layer or air gap of a microstructured optical fiber to form a carbon coating.

[0041] First of all, Figure 2 (1) is a carbon-containing gas source (i.e., a gas source to be cracked, including but not limited to carbon-containing gases such as acetylene and methane); (2) is an inert gas source: including but not limited to inert protective gases such as nitrogen and argon that are not easily reacted;

[0042] Subsequently, gas premixing is performed at (3), where the pyrolyzed gas and inert gas are premixed in a certain proportion; the premixing ratio of the pyrolyzed gas and the inert gas source varies depending on the carbon content of the pyrolyzed gas; the premixing ratio also varies depending on the optical fiber preparation parameters; and the premixing ratio also varies depending on the optical fiber structure. Taking acetylene and argon as an example, the preparation... Figure 1 For optical fibers fabricated at a fiber fabrication speed of 100 m / min, the optimal premixing ratio of acetylene and argon is 2:1.

[0043] Depending on the different process parameters, the premixing ratio of the pyrolyzed gas and other gases ranges from (1:99) to (99:1).

[0044] then, Figure 2 (4) is a gas injection device at the tail end of the optical fiber preform, which introduces the mixed gas into the air layer (air hole or air gap) in the optical fiber preform (5) which has a certain microstructure.

[0045] Figure 2 (6) is a high-temperature heating furnace, whose main function is to melt the optical fiber preform and form it into a filament. In this utility model, it also plays the role of high-temperature cracking of carbon-containing gas, forming a carbon coating inside the optical fiber structure. Finally, (7) is obtained as a finished optical fiber with an internal carbon coating. Various coating methods can be applied to the external surface of the optical fiber to form an external coating layer.

[0046] The fiber fabrication method of this invention involves depositing a carbon coating inside the microstructured fiber. The carbon coating is formed directly during the melting and fiber-forming process of the fiber preform by heating a mixture of pyrolysis gas and inert gas in a high-temperature furnace. The gas or liquid vapor pyrolysis process occurs directly within the fiber preform structure, with heat provided directly by the fiber drawing furnace, eliminating the need for an additional gas pyrolysis reactor. This method saves energy, prevents carbon powder accumulation in the pyrolysis reactor, and thus does not limit the fiber fabrication length.

[0047] The above are merely preferred embodiments of the present utility model and are not intended to limit the implementation methods and protection scope of the present utility model. Those skilled in the art should realize that any equivalent substitutions and obvious changes made using the content of this specification and illustrations should be included within the protection scope of the present utility model.

Claims

1. A carbon-coated optical fiber containing a dense carbon layer, characterized in that, include: An outer cladding structure, wherein an optical fiber core is provided in the outer cladding structure, and an air layer is formed between the inner wall of the outer cladding structure and the outer wall of the optical fiber core. At least one carbon coating is formed between the air layer and the outer wall of the optical fiber core, and / or between the inner wall of the outer cladding and the air layer.

2. The carbon-coated optical fiber according to claim 1, characterized in that, A support tube, support rod, or support arm is provided between the inner wall of the outer cladding and the outer wall of the optical fiber core, so that an air-filled gap is formed between the inner wall of the outer cladding and the outer wall of the optical fiber core, thereby forming the air layer.

3. The carbon-coated optical fiber according to claim 2, characterized in that, The number of the support tube, support rod, or support arm is at least one.

4. The carbon-coated optical fiber according to claim 1, characterized in that, The diameter of the optical fiber core rod ranges from 5 to 800 micrometers.

5. The carbon-coated optical fiber according to claim 1, characterized in that, The diameter of the outer cladding layer ranges from 15 to 1500 micrometers.

6. The carbon-coated optical fiber according to claim 1, characterized in that, The thickness of the air layer ranges from 1 to 100 micrometers.

7. The carbon-coated optical fiber according to claim 1, characterized in that, The thickness of the carbon coating ranges from 10 to 2000 nanometers.

8. The carbon-coated optical fiber according to claim 1, characterized in that, The optical fiber core is an optical fiber waveguide structure.

9. The carbon-coated optical fiber according to claim 1, characterized in that, The optical fiber core rod is made of germanium-doped quartz, fluorine-doped quartz, rare earth-doped quartz, soft glass, or chalcogenide glass.

Images