JP2008096813A - Optical fiber ribbon for installation in structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber ribbon for installation in a structure, with reduced initial transmission loss. <P>SOLUTION: The optical fiber ribbon 1 for installation in a structure is equipped with an optical fiber 2, a plurality of fibers 3 arranged on the periphery of the optical fiber 2, and a resin body 4 which is formed in a long ribbon shape in the axial direction of the optical fiber, with these optical fiber 2 and the fibers 3 embedded therein, wherein there are provided along the optical fiber 2 linear members 5 that protect the optical fiber 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tape-like optical fiber for laying a structure that reduces initial transmission loss.

  The tape-like optical fiber for laying a structure is intended to measure the strain applied to the structure by laying it by fixing it to the surface of the structure or by embedding it in the structure.

  The principle of strain measurement will be described with reference to FIG. Scattered light is generated from the optical fiber through which the light source light propagates. As shown in FIG. 4, the scattered light has different wavelength bands depending on the type, and Brillouin scattered light exists on the long wavelength side and the short wavelength side of the wavelength λ0 of the Rayleigh scattered light. Stokes light in the scattered light exists, and anti-Stokes light in the Raman scattered light exists on the short wavelength side. The shift amount (wavelength difference) of the Brillouin scattered light with respect to the wavelength λ0 of the Rayleigh scattered light depends on the distortion of the optical fiber. Therefore, distortion can be measured by detecting this shift amount.

  In addition, since the intensity ratio between Stokes light and anti-Stokes light depends on temperature, the temperature can be measured by detecting this intensity ratio.

  A conventional tape-like optical fiber for laying a structure is one in which a polyimide-coated fiber is embedded in a thermoplastic resin reinforced with a unidirectional glass fiber body (see Non-Patent Document 1). A unidirectional glass fiber body is one in which a plurality of individual fibers are aligned and oriented in the same direction.

  As shown in FIG. 5, the tape-like optical fiber 51 for laying a structure uses a unidirectional glass fiber body (not shown), a plurality of glass fibers 53 around the optical fiber 52, and all the glass fibers. The resin body 54 is formed in a tape shape that is long in the axial direction of the optical fiber 52 by placing the optical fiber 52 and the glass fiber 53 with the resin 57. is there. In the tape-like optical fiber 51 for laying the structure, the mechanical strength of the resin body 54 is reinforced by the glass fiber 53, and the resin 57 of the resin body 54 is made of a thermoplastic resin. It has heat resistance that enables strain measurement even underneath.

  Since the thermoplastic resin needs to be softened by heating to a predetermined temperature when buried around the optical fiber 52 and the glass fiber 53 as the resin 57, the thermoplastic resin has a heat resistant temperature of 300 ° C. Polyimide resin, which is a heat-resistant coating material for sensors, is used.

  However, as shown in FIG. 5, the tape-like optical fiber 51 for laying a structure in which all the glass fibers 53 are arranged in the axial direction of the optical fiber 52 is free from shear stress acting in a direction perpendicular to the optical fiber 52. Although sufficient mechanical strength can be maintained, it is difficult to maintain sufficient mechanical strength against shear stress acting in the axial direction of the optical fiber 52, and cracks and cracks are likely to occur in the axial direction of the optical fiber 52. Easy to tear.

  Therefore, as shown in FIG. 6, the glass fibers 63 are arranged in two directions, ie, the axial direction of the optical fiber 62 and the tape width direction (= direction perpendicular to the optical fiber), thereby acting in the axial direction of the optical fiber 62. A tape-like optical fiber 61 for laying a structure has been devised in which the resin body 64 can maintain sufficient mechanical strength against shear stress.

  The tape-like optical fiber 61 for laying the structure has not only the above-described reinforcing effect, but also the glass fiber 63 oriented in the direction perpendicular to the optical fiber 62 is lighted when the resin body 64 is twisted around the axis of the optical fiber 62. Since a shear stress is applied to the glass fiber 63 oriented in the axial direction of the fiber 62, the resin body 64 can be split together with the glass fiber 63 in the tape width direction. Thereby, as shown in FIG. 7, the resin body 64 can be torn and the internal optical fiber 62 can be taken out, so that the processing for mounting the connector is easy.

  In order to reduce an increase in transmission loss due to bending or local distortion, for example, the amount of germanium added to the core is reduced in the optical fiber incorporated in the tape-like optical fibers 51 and 61 for laying the structure in FIGS. Increase the relative refractive index difference between the core and the clad to be higher than that of the single mode fiber, or provide multiple holes on the circumference around the clad core to equalize the average refractive index of the clad For example, a holey fiber that is smaller than the core is used.

B. Glistic, D.C. Inaudi, “Integration of long-gage fiber-optical sensor into a fiber-reinformed composite sensing tape, 16th International Conference on Optical 13

  A manufacturing method of the tape-like optical fiber for laying the structure of FIG. 6 will be described with reference to FIG.

  As shown in FIG. 8, the optical fiber 62 is sandwiched between the bidirectional glass fiber bodies 66 from the tape thickness direction. The bi-directional glass fiber body 66 is a structure in which a plurality of glass fibers 63 are orthogonally arranged in a cross structure. One glass fiber 63 is arranged in the axial direction of the optical fiber, and the other glass fiber 63 is arranged in the tape width direction.

  A thermoplastic resin 67 such as vinyl ester is stacked on both outer sides of the bi-directional glass fiber body 66 in the tape thickness direction, and a peeling tape 68 is further stacked on both outer sides thereof. A heat application plate 69 is applied to one peeling tape 68 and a weight application plate (not shown) is applied to the other peeling tape 68. By pressing the weighted application plate while heating the heat application plate 69 to a temperature of about 45 ° C., for example, pressure is applied from the tape thickness direction, and the optical fiber 62 and the bidirectional glass fiber body 66 are made of the softened thermoplastic resin 67. Embed.

  However, in the state of FIG. 8 before applying heat and pressure, there is a gap between the two bidirectional glass fiber bodies 66 sandwiching the optical fiber 62. When the pressure is applied by the weight application plate, the bi-directional glass fiber body 66 narrows the gap, so that the glass fiber 63 perpendicular to the optical fiber in the bi-directional glass fiber body 66 is shown in FIG. Is bent so as to surround the optical fiber 62, and the stress is applied to the optical fiber 62. The optical fiber 62 is squeezed in the radial direction by this stress, causing bending and local distortion. As a result, the transmission loss of the structure-laying tape-like optical fiber 61 is increased.

  When the thermoplastic resin 67 is molded (embedded) and then cooled and cured, the thermoplastic resin 67 is cured while shrinking. Therefore, when the bi-directional glass fiber body 66 is deformed in association with the curing thermoplastic resin 67, the glass fibers 63 perpendicular to the optical fiber in the bi-directional glass fiber body 66 press the optical fiber 62. As a result, transmission loss increases. At the same time, since the thermoplastic resin 67 contracts in the axial direction of the optical fiber 62, an axial stress is applied to the optical fiber 62.

  When an axial stress is applied to the optical fiber 62, the optical fiber 62 undulates and a small bend occurs, leading to an increase in transmission loss.

  As described above, in the tape-like optical fiber 61 for laying the structure of FIG. 6, the increase in transmission loss due to local distortion applied at the time of manufacture remains fixed on the product due to the hardening of the thermoplastic resin 67, and the initial transmission loss. It becomes. For this reason, it is not sufficient to reduce transmission loss due to bending or local distortion applied during or after manufacture using a high delta optical fiber or holey fiber.

  Therefore, an object of the present invention is to provide a tape-like optical fiber for laying a structure that solves the above-described problems and reduces initial transmission loss.

  In order to achieve the above object, the present invention provides an optical fiber, a plurality of fibers arranged around the optical fiber, and the optical fiber and the fiber embedded in a resin so as to be formed in a tape shape long in the axial direction of the optical fiber. A tape-like optical fiber for laying a structure provided with the resin body is provided with a linear member that protects the optical fiber along the optical fiber.

  The linear members may be arranged on both sides of the optical fiber in the tape width direction.

  The outer diameter of the linear member may be the same as or larger than the outer diameter of the optical fiber.

  The radial rigidity of the linear member may be stronger than the radial rigidity of the optical fiber.

  The axial rigidity of the linear member may be made stronger than the axial rigidity of the optical fiber.

  The bending rigidity of the linear member may be weaker than the bending rigidity of the optical fiber.

  The said linear member is good also as either an optical fiber, a metal wire, glass fiber, and a resin wire.

  The fiber arrangement direction may be two directions, that is, the axial direction of the optical fiber and the tape width direction.

  The fiber may be any of glass fiber, aramid fiber, carbon fiber, and POB (poly-p-phenylenebenzobisoxazole) fiber.

  The resin of the resin body may be any of unsaturated polyethylene resin, vinyl ester resin, epoxy resin, polyimide resin, polyphenylene sulfide resin, polyether ether ketone resin, and polybutene.

  The optical fiber may be either a high delta optical fiber or a holey fiber.

  The present invention exhibits the following excellent effects.

  (1) The initial transmission loss can be reduced.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, a tape-like optical fiber 1 for laying a structure according to the present invention includes an optical fiber 2, a plurality of fibers 3 arranged around the optical fiber 2, the optical fibers 2 and the fibers. In a structure-laying tape-like optical fiber 1 having a resin body 4 formed by embedding 3 in a resin 7 and having a long tape shape in the axial direction of the optical fiber 2, the optical fiber 2 is arranged along the optical fiber 2. A linear member 5 to be protected is provided.

  In this embodiment, the linear members 5 are arranged on both sides of the optical fiber 2 in the tape width direction so as to be in contact with the optical fiber 2 in parallel with the optical fiber 2. The outer diameter of the linear member 5 is the same as the outer diameter of the optical fiber 2. Examples of the linear member 5 include an optical fiber, a metal wire, a glass fiber, and a resin wire used for a tension member (strength member) for an optical cable that are generally used for communication.

  The optical fiber 2 is a single mode fiber (clad diameter 125 ± 1 μm, outer diameter about 145 μm) having a core 13 and a clad 14 and coated with a polyimide resin 15 on the outer periphery thereof.

  In this embodiment, the optical fiber 2 is sandwiched by bi-directional glass fiber bodies from both sides of the tape thickness direction so that the arrangement direction of the fibers 3 is two directions of the axial direction of the optical fiber 2 and the tape width direction (FIG. 8). reference). Examples of the fiber 3 include glass fiber, aramid fiber, carbon fiber, and POB (poly-p-phenylenebenzobisoxazole) fiber.

  The resin of the resin body 4 is a thermosetting resin, such as an unsaturated polyethylene resin, a vinyl ester resin, an epoxy resin, a polyimide resin, a polyphenylene sulfide resin, a polyether ether ketone resin, or a polybutene.

  The manufacturing method of the structure-laying tape-like optical fiber 1 is substantially the same as the method described with reference to FIG. 8, except that the linear member 5 extends along the optical fiber 2.

  Next, the effect of the structure-laying tape-like optical fiber 1 will be described.

  Since the tape-like optical fiber 1 for laying a structure of the present invention has a linear member 5 along the optical fiber 2, when the resin contracts in the axial direction at the time of manufacture, the linear member 5 serves as a tension member. As a result, the compressive strain in the axial direction applied to the optical fiber 2 can be reduced.

  By reducing the compressive strain in the axial direction, it is possible to prevent a small bend from occurring in the axial direction of the optical fiber 2, thereby reducing the transmission loss of the optical fiber 2.

  Similarly to FIG. 8, when the pressure is applied by the weighted application plate and the bi-directional glass fiber body 6 narrows the gap, the fibers 3 perpendicular to the optical fiber 2 are formed as shown in FIG. 2 and bend so as to surround the linear member 5. At this time, the stress due to the bending is mainly applied to the linear member 5. Therefore, the stress applied to the optical fiber 2 is relaxed compared to the case of FIG. That is, the linear member 5 serves as a cushioning material (buffer material), and compressive strain applied in the radial direction of the optical fiber 2 is reduced, so that bending and local strain of the optical fiber 2 are reduced. In this way, it is possible to reduce the increase in transmission loss of the structure-laying tape-like optical fiber 1 at the time of manufacture, and to reduce the initial transmission loss.

  Next, another embodiment of the present invention will be described.

  Since the linear member 5 plays the role of a tension member, it is desirable that the rigidity in the axial direction is as large as possible. For example, the linear member 5 is preferably stronger than the rigidity in the axial direction of the optical fiber 2. The axial rigidity can be expressed, for example, by Young's modulus.

   Further, it is desirable that the linear member 5 has sufficiently large (strong) radial rigidity compared to the optical fiber 2 in order to concentrate the stress applied to the linear member 5 according to the principle of FIG. The radial rigidity can be expressed, for example, by Young's modulus.

  Furthermore, since it is conceivable that the tape-like optical fiber 1 for laying a structure is bent and laid, it is desirable that the bending rigidity of the linear member 5 is sufficiently smaller (weak) than the bending rigidity of the optical fiber. If the bending rigidity is too strong, problems such as difficulty in installation occur when the tape-like optical fiber 1 for laying a structure is installed in a curved portion.

  The bending rigidity of the linear member 5 is defined as E · I by the Young's modulus E and the sectional second moment I determined by the sectional structure of the linear member 5. However, it is desirable that the specific numerical value indicating the degree of bending rigidity or less be appropriately set in consideration of the installation location.

  In the embodiment of FIG. 1, since the outer diameter of the linear member 5 is the same as the outer diameter of the optical fiber 2, it is easy to align the positions of the central axes of the linear member 5 and the optical fiber 2 in the tape thickness direction. Become. On the other hand, by making the outer diameter of the linear member 5 larger than the outer diameter of the optical fiber 2, the fibers 3 perpendicular to the optical fiber 2 in the bidirectional glass fiber body 6 do not touch or press the optical fiber 2. It becomes difficult. Therefore, it is possible to reduce an increase in transmission loss of the structure-laying tape-like optical fiber 1 at the time of manufacture and to reduce an initial transmission loss.

  In the embodiment of FIG. 1, the optical fiber 2 is a single mode fiber, but an optical fiber having a small increase in transmission loss with respect to strain, such as a high delta optical fiber or a holey fiber (for example, a cladding diameter of 80 ± 1 μm and an outer diameter of about 100 μm). Should be used.

  In the embodiment of FIG. 1, the optical fiber 2 is a single body and the linear members 5 are arranged on both sides thereof. However, as shown in FIG. 3, a plurality of optical fibers (types are single mode fibers, high deltas). Also in the tape-like optical fiber 31 for laying a structure in which the linear member 35 is embedded in the resin body 34 along the both sides in the width direction of the tape-like optical fiber in which the optical fibers 32 and the holey fiber 32 are arranged in parallel. The same effect as described can be obtained.

  Since the present invention protects the optical fiber 2 by providing the linear member 5 along the optical fiber 2, the optical fiber 2 is protected regardless of the direction of the plurality of fibers 3. can do. In particular, in the above embodiment, since the fiber 3 is arranged in two directions, ie, the axial direction of the optical fiber 2 and the tape width direction, the strength against the shear stress in the tape width direction is enhanced, and FIG. The advantage that such processing becomes easy can be utilized as it is.

  If the resin body 4 is twisted around the axis of the optical fiber 2, the resin body 4 can be split along with the glass fibers 3 in the tape width direction. Thereafter, the optical fiber 2 and the linear member 5 are individually cut into necessary lengths and subjected to processing such as connector mounting.

  Since the present invention can reduce the initial transmission loss, the overall increase in transmission loss can be significantly reduced as a result.

It is the perspective view with a cross section and the cross-sectional enlarged view of the tape-shaped optical fiber for constructing a structure showing an embodiment of the present invention. It is the resin body perspective view which showed a mode that it was hard to add stress from a fiber to the optical fiber in the tape-form optical fiber for structure laying of this invention. It is a perspective view with a section of a tape optic fiber for constructing a structure which shows one embodiment of the present invention. It is a wavelength distribution map of the scattered light in an optical fiber. It is the perspective view with a cross section and the cross-sectional enlarged view of the conventional tape-shaped optical fiber for structure laying. It is the perspective view with a cross section and the cross-sectional enlarged view of the conventional tape-shaped optical fiber for structure laying. It is a perspective view with a cross section which shows the terminal processing state of the tape-form optical fiber for structure laying. It is sectional drawing which shows the manufacturing method of the tape-form optical fiber for structure laying. It is the resin body perspective view which showed a mode that stress was added to the optical fiber from the fiber in the conventional tape-form optical fiber for structure laying.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tape-like optical fiber for structure laying 2 Optical fiber 3 Fiber 4 Resin body 5 Linear member 7 Resin

Claims (11)

  Laying a structure comprising an optical fiber, a plurality of fibers arranged around the optical fiber, and a resin body formed by embedding the optical fiber and the fiber with a resin and formed in a tape shape long in the axial direction of the optical fiber A tape-like optical fiber for laying a structure, characterized in that a linear member for protecting the optical fiber is provided along the optical fiber.   2. The tape-like optical fiber for laying a structure according to claim 1, wherein the linear members are respectively arranged on both sides of the optical fiber in the tape width direction.   The tape-shaped optical fiber for laying a structure according to claim 1 or 2, wherein an outer diameter of the linear member is equal to or larger than an outer diameter of the optical fiber.   The tape-shaped optical fiber for laying a structure according to any one of claims 1 to 3, wherein the radial rigidity of the linear member is made stronger than the radial rigidity of the optical fiber.   The tape-like optical fiber for laying a structure according to any one of claims 1 to 4, wherein the axial rigidity of the linear member is made stronger than the axial rigidity of the optical fiber.   6. The tape-like optical fiber for laying a structure according to claim 1, wherein the bending rigidity of the linear member is weaker than that of the optical fiber.   The tape-like optical fiber for laying a structure according to any one of claims 1 to 6, wherein the linear member is any one of an optical fiber, a metal wire, a glass fiber, and a resin wire.   The tape-like optical fiber for laying a structure according to any one of claims 1 to 3, wherein the fiber is arranged in two directions, ie, an axial direction of the optical fiber and a tape width direction.   The tape-like light for laying a structure according to any one of claims 1 to 8, wherein the fiber is any one of glass fiber, aramid fiber, carbon fiber, and POB (poly-p-phenylenebenzobisoxazole) fiber. fiber.   The resin of the resin body is any one of unsaturated polyethylene resin, vinyl ester resin, epoxy resin, polyimide resin, polyphenylene sulfide resin, polyether ether ketone resin, and polybutene. Tape-like optical fiber for laying structures.   The tape-like optical fiber for laying a structure according to any one of claims 1 to 10, wherein the optical fiber is a high delta optical fiber or a holey fiber.

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