Optical Fiber Bundle

Abstract

To provide an optical fiber having no generation of outgassing in usage under vacuum environment.SOLUTION: An optical fiber 10 is used under vacuum environment. The optical fiber 10 comprises a quartz-made bare fiber 11 and a metallic jacket 12 covering the bare fiber.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention ,light Regarding fiber bundles. [Background technology]

[0002] When an optical fiber is used in a vacuum vessel, outgassing from the resin jacket of the optical fiber becomes a problem. Patent Document 1 discloses that, in order to prevent the outgassing, optical windows are provided in the metal fittings at both ends of a flexible tube, and an optical fiber bundle is housed therein. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4060211 Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to provide an optical fiber that does not generate outgassing when used in a vacuum environment. An optical fiber bundle is made up of multiple The purpose of this project is to provide [Means for solving the problem]

[0005] The present invention relates to The optical fiber includes a bare fiber made of quartz and a metal jacket covering the bare fiber. Optical fiber used in a vacuum environment In the optical fiber bundle, a plurality of optical fibers are collected, and at the tip portion, the plurality of optical fibers are bundled and integrated with an adhesive, and the adhesive is an alumina adhesive or a ceramic adhesive. . Effect of the Invention

[0007] According to the present invention, since the bare quartz fiber is covered with the metal jacket, no outgassing occurs when used in a vacuum environment. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of an optical fiber according to an embodiment. [Diagram 2] 2 is a cross-sectional view of the tip of an optical fiber bundle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The embodiments will be described in detail below.

[0010] 1 shows an optical fiber 10 according to an embodiment. The optical fiber 10 is used for spectroscopic measurement or the like in a vacuum environment, for example, in a vacuum container. Here, "vacuum" in this application refers to a state in a space filled with gas at a pressure lower than atmospheric pressure, specifically, a state in a space filled with gas at a pressure lower than 1013 hPa.

[0011] The optical fiber 10 according to the embodiment includes a bare fiber 11 made of quartz and a metal jacket 12 that covers the bare fiber 11. The outer diameter of the optical fiber 10 is, for example, not less than 130 μm and not more than 1620 μm.

[0012] The bare fiber 11 has a core 111 with a relatively high refractive index at the center of the fiber, and a cladding 112 with a relatively low refractive index that covers the core 111. The outer diameter of the bare fiber 11 is, for example, not less than 125 μm and not more than 1500 μm. The diameter of the core 111 is, for example, not less than 50 μm and not more than 1200 μm. The thickness of the cladding 112 is, for example, not less than 5 μm and not more than 60 μm.

[0013] In the quartz bare fiber 11, for example, the core 111 may be formed of pure quartz not doped with a dopant, and the clad 112 may be formed of quartz doped with a dopant that lowers the refractive index, such as fluorine (F). Alternatively, the core 111 may be formed of quartz doped with a dopant that increases the refractive index, such as germanium (Ge), and the clad 112 may be formed of pure quartz not doped with a dopant, or quartz doped with a dopant that lowers the refractive index, such as fluorine (F).

[0014] Examples of metals that form the metal jacket 12 include aluminum (Al), gold (Au), and alloys thereof. Of these, the metal jacket 12 is preferably formed of aluminum or an aluminum alloy. The thickness of the metal jacket 12 is, for example, 2.5 μm or more and 60 μm or less.

[0015] The optical fiber 10 according to the embodiment can be manufactured by heating a quartz preform to draw a bare fiber 11, and then passing the drawn bare fiber 11 through a bath of molten metal to coat it with a metal jacket 12.

[0016] According to the optical fiber 10 according to the embodiment having the above configuration, the bare quartz fiber 11 is covered with the metal jacket 12, so there is no source of outgassing, and therefore no outgassing is generated when used in a vacuum environment.

[0017] 2, a plurality of optical fibers 10 according to the embodiment can be collected and bundled to form an optical fiber bundle 20. The number of optical fibers 10 constituting the optical fiber bundle 20 is, for example, 2 or more and 3000 or less.

[0018] In the optical fiber bundle 20, a plurality of optical fibers 10 are bundled and integrated at the tip portion thereof via an adhesive 21, and may be inserted into and bonded to a cylindrical metal sleeve S. From the viewpoint of preventing outgassing, the adhesive 21 is preferably a silicone adhesive, an alumina adhesive, or a ceramic adhesive.

[0019] The optical fiber 10 according to the embodiment or the optical fiber bundle 20 using the same can be inserted into a flexible tube and provided with optical connectors on both ends to form an optical cable.

[0020] In the outgassing prevention structure disclosed in Patent Document 1, light enters the optical fiber through the optical window, and the light emitted from the optical fiber is transmitted through the optical window. Therefore, in order to obtain proper transmission of light, it is necessary to accurately position the end face of the optical fiber relative to the optical window. Therefore, the length of the optical fiber must correspond to the length of the flexible tube. In addition, there is a problem that the amount of transmitted light decreases because the light is reflected by the optical window.

[0021] In contrast, in the optical fiber 10 according to the embodiment and the optical fiber bundle 20 using the same, light is directly incident and outgoing light is transmitted without passing through an optical window, so the length of the optical fiber 10 and the optical fiber bundle 20 is not restricted by the length of the flexible tube. In addition, there is no reduction in the amount of transmitted light. [Industrial Applicability]

[0022] The present invention ,light It is useful in the field of fiber bundles. [Explanation of symbols]

[0023] 10 Optical Fiber 11 Bare Fiber 111 cores 112 Clad 12 Metal Jacket 20 Optical Fiber Bundles 21 Adhesive S Metal Sleeve

Claims

1. An optical fiber bundle including a plurality of optical fibers used in a vacuum environment, the optical fiber bundle including a bare quartz fiber and a metal jacket covering the bare fiber, The optical fiber bundle has a tip portion where the optical fibers are bundled and integrated with an adhesive, the adhesive being an alumina adhesive or a ceramic adhesive.

2. 2. The optical fiber bundle according to claim 1, The optical fiber bundle, wherein the metal jacket is made of aluminum or an aluminum alloy.

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