JP2006276461A - Optical fuse - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fuse which opens an optical circuit when excessive light is inputted to the optical circuit and is easy to replace even after fracture. <P>SOLUTION: An overcoat part 5 has transparent portions 5a and 5b which come into contact with at least cores of optical fibers 6a and 6b (2.A). An optical fuse 100 where no core is formed is mounted and lights having a wavelength at which photosetting resin 1 can be cured are introduced in the optical fibers 6a and 6b from both sides (2.B). A core 1c is formed of cured resin in uncured photosetting resin 1 to form a waveguide by a refractive index difference from the uncured photosetting resin 1 (2.C). When a light with excessive intensity is inputted during use of the optical fuse 150, carbon powder 3 generates heat with a light leaking from the core 1c. Consequently, the core 1c is fused in the uncured photosetting resin 1 and the waveguide disappears, so the optical circuit is opened. Then the cause of the excessive light input is removed, the optical fuse 150 in a muddy state is replaced with a new optical fuse 100 wherein no core is formed, and the procedures 2.B and 2.C are repeated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical fuse that opens a circuit when excess light is input to the optical circuit.

By placing a low-melting glass or metal thin film such as TeO _{2 in} the middle of the optical circuit, when the light input exceeds the specified light intensity, the low-melting glass or metal thin film melts and opens the optical circuit. Therefore, an optical fuse is proposed (Patent Document 1, Non-Patent Document 1). It has also been proposed to combine an MEMS shutter and a photovoltaic cell to form an optical fuse.
JP-A-11-281842 Jpn. J. Appl. Phys. 43 (2004) L256

Patent Document 1 has a configuration in which an optical fuse composed of a light exothermic material film and a film that changes light transmittance according to heat is sandwiched between two end faces of optical fibers. The technique of Non-Patent Document 1 is to connect the terminals of _two optical fibers directly with a low-melting glass such as TeO ₂ . Since these are difficult to align with each other, it is not easy to restore them after they are broken once. When an optical fuse is formed by combining a MEMS shutter and a photovoltaic cell, the system becomes complicated and expensive.

  Accordingly, the present inventors have conceived a replaceable optical fuse configured in a transparent container or the like and completed the present invention.

  The invention according to claim 1 is such that the housing having a transparent portion with respect to light having a desired wavelength is provided at at least two opposing locations, and the two transparent portions are connected to the inside thereof. A transparent core formed by forming photocuring, an uncured photocurable resin surrounding the core, a holding material that holds the uncured photocurable resin so as not to leak to the outside, and a photothermal conversion material It is an optical fuse characterized by having.

  Further, the invention according to claim 2 is configured to connect a housing having a transparent portion with respect to light having a desired wavelength at least at two opposite locations, and the two transparent portions inside the housing. And having a transparent core part formed by self-forming photocuring and an uncured photocurable resin surrounding the core part, and covering parts other than the two transparent parts with a photothermal conversion material This is an optical fuse. According to a third aspect of the present invention, in the optical fuse according to the first or second aspect, the core portion has a melting point or a glass transition point of 150 ° C. or lower.

  The invention according to claim 4 is held so as to connect the housing having a transparent portion with respect to light of a desired wavelength at at least two opposite locations, and the two transparent portions at the inside thereof. And an uncured photocurable resin that can be cured by self-forming photocuring, a holding material that holds the uncured photocurable resin so as not to leak to the outside, and a photothermal conversion material. It is an optical fuse.

  Further, the invention according to claim 5 is configured to connect a housing having a transparent portion with respect to light having a desired wavelength at at least two opposing locations, and the two transparent portions at the inside thereof. An optical fuse comprising an uncured photocurable resin that is held by self-forming photocuring and having a portion other than two transparent portions covered with a photothermal conversion material. The invention according to claim 6 is the optical fuse according to claim 4 or 5, wherein the photocurable resin has a melting point or glass transition point of a cured product of 150 ° C. or lower. .

  Various self-forming optical waveguides have been proposed by the applicants of the present application. For example, JP-A-2002-365459, JP-A-2002-169038, and JP-A-2004-149579. When the photocurable resins described in these are used, the alignment is very easy. Thus, if a core that is weak against heat is used as the core in which the axis alignment is performed in a self-forming manner, it functions as an optical fuse.

  This is because if the core surrounded by uncured photo-curing resin receives more than a certain amount of light, the leaked light leaking outside the core will be converted into heat by the outer photothermal conversion material, and the fuse will be at about 150 ° C. This is because the temperature is increased. As a result, if the core melts, the core disappears, and the optical loss increases, so that excessive light output can be prevented. At this time, if the holding material also melts and becomes turbid with the uncured photocurable resin, the light loss increases.

  A distinguishing feature of the present invention is that an optical fuse that is broken can be replaced with the entire housing. After replacing the optical fuse according to any one of claims 4 to 6, a core can be formed by introducing light having a core forming wavelength from optical fibers or the like on both sides of the fuse.

  As the photocurable resin, for example, an arbitrary photocurable resin described in JP-A No. 2002-36559, JP-A No. 2002-169038, or JP-A No. 2004-149579 may have a low melting point or glass transition point. good. In this respect, it is desirable to use a (meth) acrylic or epoxy resin. Further, using two kinds of resins described in JP-A-2002-169038 and JP-A-2004-149579, which are different in refractive index from the curing mechanism, the resin is cured at a wavelength that cures only a photo-curing resin having a high refractive index. May be. In this case, the remaining uncured resin mixture may be thermally cured, for example.

  Any material can be used for the holding material. When a synthetic resin having a low melting point or glass transition point is used, the holding material is melted together with the core and becomes turbid with the photocurable resin, so that the light loss can be increased.

  Any material can be used as the photothermal conversion material. In particular, carbon powder (graphite) is inexpensive and suitable. The photothermal conversion material may be disposed on the outer periphery of the holding material or may be dispersed inside the holding material. If a holding material made of a synthetic resin having a low melting point or glass transition point is used, the holding material also melts together with the core melting, and the photothermal conversion material can also become turbid with the photocurable resin, so that the light loss can be further increased. it can.

  FIG. 1 is a cross-sectional view showing the configuration of a specific example of an optical fuse 100 according to the present invention. FIG. A is a cross-sectional view parallel to the optical path, FIG. B is a cross-sectional view perpendicular to the optical path.

  FIG. As shown in A and B, inside the optical fuse casing 4 made of transparent rectangular heat-resistant glass, a holding material in which the uncured photocurable resin 1 in a cylindrical shape parallel to the optical path is made of a cylindrical resin cured product 2 and is filled with a photothermal conversion material 3 made of carbon powder (graphite). The holding material 2 composed of the uncured photocurable resin 1 and the cylindrical resin cured product is configured to connect two opposing surfaces of the optical fuse casing 4, and the uncured photocurable resin 1. In the portion, light can be transmitted from one side of the optical fuse casing 4 to the opposite side.

  FIG. 2 is a cross-sectional view showing how to use a specific example of the optical fuse 100 according to the present invention. FIG. 1A is a cross-sectional view showing an optical fuse mantle portion 5 for mounting the optical fuse 100 of FIG. 1 and optical fibers 6a and 6b connected thereto. The optical fuse jacket 5 is formed in a rectangular box shape without an upper surface, and at least the portions 5a and 5b in contact with the cores of the optical fibers 6a and 6b are transparent.

  FIG. As in B, the optical fuse 100 without a core is placed on the optical fuse jacket 5 to which the optical fibers 6a and 6b are connected, and the photocurable resin 1 is cured from both sides of the optical fibers 6a and 6b. Introducing light of a wavelength that can be obtained. For example, a near ultraviolet to purple or blue laser may be used in accordance with the absorption edge of the photopolymerization initiator incorporated in the photocurable resin 1. Then, a core 1c made of a photocurable resin cured product is formed in the uncured photocurable resin 1 of the optical fuse 100 in accordance with the optical path, and due to a difference in refractive index from the uncured photocurable resin 1. A waveguide is formed (FIG. 2.C). An optical fuse 150 is formed with an optical waveguide. As described in the above-mentioned patent publication of the present applicant, the optical fuse 150 is formed with a waveguide with little optical loss and can be used as a part of an optical circuit together with the optical fibers 6a and 6b.

  If excessive intensity light is input to the optical fuse 150 from at least one of the optical fibers 6a and 6b, a large amount of light leaks from the core 1c. The leaked light may cure the uncured photocurable resin 1 on the outer periphery of the core 1c, but in any case, the light leaked from the core 1c reaches the carbon powder 3 on the outer periphery and generates heat. Then, for example, if the core 1c is a (meth) acrylate resin and the melting point or glass transition point is 150 ° C. or lower, the core 1c melts into the uncured photocurable resin 1 at 150 ° C. Disappears. At this time, if the retaining agent 2 is also melted, the external carbon powder becomes cloudy. The optical circuit is opened due to the disappearance of the waveguide inside the optical fuse 150 and the turbidity of the carbon powder.

  Thereafter, the cause of the excessive light input is eliminated, and the opacified optical fuse 150 in which turbidity is generated is replaced with a new optical fuse 100 having no core formed thereon. B and 2. By repeating the procedure C, the optical circuit can be closed. Thus, according to the present embodiment, it is possible to provide an optical fuse that does not require axial alignment and can be easily replaced after being broken.

  The optical fuse 150 in the above embodiment corresponds to the specific examples of claims 1 and 3, and the optical fuse 100 corresponds to the specific examples of claims 4 and 6.

  As can be easily considered, the same effect as in the above embodiment can be obtained by using the holding member in the above embodiment as a housing and covering the outer periphery of the housing with a photothermal conversion material. This corresponds to the specific examples of claims 2 and 5.

1 is a cross-sectional view showing the configuration of a specific example of an optical fuse according to the present invention. Sectional drawing which shows the usage method of one specific Example of the optical fuse which concerns on this invention.

Explanation of symbols

1: Uncured photo-curing resin 1c: Core made of photo-curing resin cured product 2: Holding material 3: Photothermal conversion material 4: Optical fuse casing 5: Optical fuse casing 6a, 6b: Optical fiber

Claims (6)

A housing having a portion transparent to a desired wavelength light at least at two opposite positions;
Inside it,
A transparent core formed by self-forming photocuring so as to connect the two transparent parts;
Uncured photo-curing resin surrounding the core,
A holding material that holds the uncured photocurable resin so that it does not leak outside;
An optical fuse comprising a photothermal conversion material. A housing having a portion transparent to a desired wavelength light at least at two opposite positions;
Inside it,
A transparent core formed by self-forming photocuring so as to connect the two transparent parts;
It has an uncured photocurable resin surrounding the core part,
An optical fuse, wherein a portion other than the two transparent portions is covered with a photothermal conversion material. The optical fuse according to claim 1, wherein the core portion has a melting point or glass transition point of 150 ° C. or less. A housing having a portion transparent to a desired wavelength light at least at two opposite positions;
Inside it,
An uncured photocurable resin that is held to connect the two transparent portions and is curable by self-forming photocuring;
A holding material that holds the uncured photocurable resin so that it does not leak outside;
An optical fuse comprising a photothermal conversion material. A housing having a portion transparent to a desired wavelength light at least at two opposite positions;
Inside, having an uncured photocurable resin curable by self-forming photocuring, held to connect the two transparent parts,
An optical fuse, wherein a portion other than the two transparent portions is covered with a photothermal conversion material. The optical fuse according to claim 4 or 5, wherein the photocurable resin has a cured product having a melting point or glass transition point of 150 ° C or lower.

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