JP2009244545A - Optical connection structure and optical connection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical connection structure and an optical connection method for achieving quick and accurate connection without requiring a series of work for forming the adhesive connection members in an end part of an optical transmission medium at every connection. <P>SOLUTION: In this optical connection structure in which the optical transmission mediums are inserted through both ends of a mechanical splice to connect the optical transmission mediums optically, the mechanical splice includes a massive adhesive connection members, and each optical transmission medium is abutted and connected on/with the adhesive connection members, respectively. In this optical connection method, the optical transmission mediums are inserted through both ends of the mechanical splice to connect the optical transmission mediums optically. The massive adhesive connection member is held in the inside of the mechanical splice, and the optical transmission mediums are inserted through both ends of the mechanical splice and are abutted on the adhesive connection members. Preferably, the adhesive connection member contains a basic material. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical connection structure and an optical connection method for connecting optical transmission media.

  Conventionally, as a method of connecting optical transmission media such as optical fibers, a method of physically connecting the optical transmission media by matching the optical transmission media or by matching the ferrules inserted with the optical transmission media is generally used. Has been adopted.

  When the optical transmission medium is permanently connected and is not changed, a mechanical splice that sandwiches and fixes the opposite optical transmission media is used in addition to the fusion connection (see, for example, Patent Document 1 or 2). When the connection is frequently attached and detached, the optical connector connection is performed after protecting the end of the optical transmission medium with a ferrule. In these cases, the opposite optical transmission media are connected by physically contacting the ends.

However, when the connection by contacting the optical transmission medium between direct, fine scratches or the like has a problem that a large influence on the connection characteristics. Even if the end surface is smooth, there is a gap between the opposing ends microscopically, and the connection loss at this portion cannot be ignored. Furthermore, since the strength of the optical transmission medium is low, there is a possibility that the optical transmission medium may be damaged when the pressing force to the end portion is increased.

  Among the methods described above, as a technique using a mechanical splice, a method is disclosed in which an adhesive connection member is provided at an end of an optical transmission medium to be connected, and then the optical transmission media are opposed to each other (for example, (See Patent Document 3). In this method, the end of one optical transmission medium is brought into contact with the adhesive connecting member sheet, and is pressed to form an adhesive connecting member layer on the end of the optical transmission medium, followed by the other optical transmission medium. Connection is made with the medium facing each other. It is disclosed that this connection can also be made in a mechanical splice.

JP 2000-241660 A JP 2002-22997 A JP 2005-274839 A

  However, in the optical connection structure described above, when the optical transmission medium is required to be connected, the adhesive connection member is moved and disconnected while the optical transmission medium is pressed against the adhesive connection member to be adhered. A series of processes such as providing a conductive connecting member layer at the end of the optical transmission medium must be performed each time, which is inefficient, and depending on the working environment when manufacturing the optical circuit, such a series of processes may be performed. There are cases where it is difficult to carry out on site, and improvements for simpler and more accurate connection have been demanded.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an end portion of an optical transmission medium every time connection is made in connection between optical transmission media using a mechanical splice structure. It is an object of the present invention to provide an optical connection structure and an optical connection method that can perform a quick and accurate connection without requiring a series of operations for forming an adhesive connection member.

  The present invention is an optical connection structure in which optical transmission media are respectively inserted from both ends of a mechanical splice, and the optical transmission media are optically connected to each other, and the mechanical splice includes a massive adhesive connection member inside. Each optical transmission medium is characterized in that it is connected in contact with an adhesive connecting member.

  The lump-like adhesive connecting member is preferably provided with a substrate therein.

  Moreover, the block-shaped adhesive connection member makes it a preferable aspect that hardness is JIS (A type) 5-100.

  Furthermore, it is preferable that the massive adhesive connecting member is a spherical adhesive connecting member.

  The present invention also relates to an optical connection method in which an optical transmission medium is inserted from both ends of a mechanical splice to optically connect the optical transmission media to each other, and a massive adhesive connection member is sandwiched inside the mechanical splice. The optical transmission medium is inserted from both ends of the mechanical splice and brought into contact with the adhesive connecting member.

  The lump-like adhesive connecting member is preferably provided with a substrate therein.

  According to the optical connection structure and the optical connection method of the present invention, when connecting the optical transmission media, the step of providing the adhesive connection member on the end of the optical transmission medium can be omitted, and both ends of the mechanical splice can be omitted. Then, it is possible to complete the connection accurately and quickly only by inserting the optical transmission medium and bringing it into contact with the adhesive connection member. In addition, connection without air mixing becomes possible. Furthermore, by defining the hardness of the adhesive connecting member, it is possible to reconnect it while being a mechanical splice.

Hereinafter, embodiments of the optical connection structure of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a perspective view schematically showing a mechanical splice structure. The mechanical splice 1 is formed by joining a holding substrate 11 and a V-groove substrate 12, and a clamp spring 14 having a U-shaped cross section is attached to the outer peripheral portion thereof to fix both substrates. The V-groove substrate 12 has a groove 13 having a V-shaped cross section penetrating from one end face into which the optical transmission medium 21 is inserted into the other end face, and the optical transmission medium 21 is guided by the groove 13. Further, the optical transmission medium 21 is fixed in the groove 13 by the holding substrate 11. Reference numeral 22 denotes a covering portion of the optical transmission medium 21 and is removed from the optical transmission medium 21 as necessary.

  FIG. 2 is a schematic cross-sectional view showing a first embodiment of an optical connection structure using the mechanical splice structure of the present invention. As shown in the figure, in the present embodiment, first, a lump-like adhesive connecting member 3 is provided in advance inside the mechanical splice 1. Next, the optical transmission medium 21 is inserted from both ends of the mechanical splice 1 and brought into contact with the adhesive connecting member 3. By these steps, the optical transmission medium is connected.

  By preparing in advance a mechanical splice that sandwiches such a massive adhesive connection member, when it is necessary to connect the optical transmission medium, only a simple process of inserting the optical transmission medium from both ends is required. Thus, the connection of the optical transmission medium can be completed, which is preferable.

  FIG. 3 is a schematic cross-sectional view showing a second embodiment of an optical connection structure using the mechanical splice structure of the present invention. As shown in the drawing, in the present embodiment, first, an adhesive connecting member is formed on the surface of the spherical base material 23 to produce a massive adhesive connecting member 3, which is provided in advance in the mechanical splice 1. Next, the optical transmission medium 21 is inserted from both ends of the mechanical splice 1 and brought into contact with the adhesive connecting member 3. In the second embodiment, similarly to the first embodiment, the optical transmission medium can be connected through these steps.

  In the first embodiment, since the bulky adhesive connection member is interposed, it is possible to prevent the end face of the optical transmission medium from being damaged as compared with the conventional connection method in which the optical transmission media are directly attached to each other. In addition, since the optical transmission medium and the adhesive connection member are in close contact with each other, the connection can be suitably performed without dropping the optical transmission medium.

  Furthermore, in 2nd Embodiment, since the base material is included in the inside of an adhesive connection member, even if it repeats connection cancellation | release and reconnection of an optical transmission medium, the shape of an adhesive connection member is maintained, and adhesiveness is carried out. The deformation of the connecting member is prevented.

  The massive adhesive connecting member of the present invention can have a spherical shape, an elliptical spherical shape, an egg shape, a rectangular parallelepiped shape, or the like. Among them, a spherical shape that is easy to come into contact with the core of the optical transmission medium without being mixed with air is preferable.

  When the spherical adhesive connecting member of the present invention is used alone, the diameter of the adhesive connecting member is preferably 30 to 125 μm. If it exceeds 125 μm, a problem arises in connection characteristics. If it is less than 30 μm, the amount of the adhesive connecting member is insufficient, and the optical transmission medium cannot be sufficiently connected. Preferably it is 40-110 micrometers, Most preferably, it is about 100 micrometers.

  When a spherical base material is included inside the spherical adhesive connecting member, the diameter of the adhesive connecting member is preferably 30 to 125 μm, particularly preferably about 100 μm. At that time, the diameter of the spherical base material is preferably 10 to 50 μm, and the thickness of the adhesive connecting member layer is preferably 5 to 100 μm.

  In addition, when an adhesive connection member is a rectangular parallelepiped shape, the film thickness is preferably 10 to 125 μm, more preferably 15 to 100 μm, and particularly preferably about 20 μm.

  The adhesive connecting member 3 may be any refractive index matching body that comes into close contact with the optical transmission medium 21 with appropriate tackiness.

  In order to have an appropriate tackiness, the adhesive strength is preferably 1 to 100 gf / 25 mm, more preferably 5 to 50 gf / 25 mm, and particularly preferably 10 to 30 gf / 25 mm.

  If the adhesive strength is less than 1 gf / 25 mm, the connection is not stable, and if it exceeds 100 gf / 25 mm, an adhesive substance adheres to the removed optical transmission medium 21, which is not preferable.

  In addition, said adhesive force is the value measured based on 90 degree peeling peel strength of JISZ0237.

  Next, in order to be a refractive index matching body, it is sufficient that the refractive index is close to that of the optical transmission medium 21. Specifically, in terms of transmission loss due to avoidance of Fresnel reflection, the difference in refractive index is preferably within ± 0.1, and particularly preferably within 0.05. In addition, when the refractive index difference of the two optical transmission media connected is large, it is preferable that the average value of these refractive indexes and the refractive index of an adhesive connection member are in the said range. The refractive index is a value at 20 ° C., and a light source having a wavelength of 1310 nm is used for measurement.

  Further, the adhesive connecting member 3 is preferably JIS (A type) 5 to 100, since cohesive failure hardly occurs and reconnection is possible as it is. More preferably, it is 20-90. The above hardness is a value measured according to JIS K-6253. In addition, the adhesive connection member 3 can be replaced and reconnected.

  The adhesive connecting member 3 includes a polymer material such as acrylic, epoxy, vinyl, silicone, rubber, urethane, methacrylic, nylon, bisphenol, diol, polyimide, and fluorinated epoxy. It is preferable to use various adhesive materials such as fluorinated acrylic.

  Of these, silicone-based and acrylic pressure-sensitive adhesive materials are particularly preferable in terms of environmental resistance and adhesiveness. Moreover, adhesive force and wettability may be adjusted by adding a crosslinking agent, an additive, a softening agent, a tackifier, and the like, and water resistance, moisture resistance, and heat resistance may be added.

  As the substrate of the present invention, it is preferable to select a substance having a refractive index close to that of the optical transmission medium. And what deform | transforms from a viewpoint which fills the gap between fibers and can prevent air mixing is preferable. Further, it is more preferable to restore the original shape when the connection is canceled from the viewpoint of enabling reconnection.

  The base material to be deformed may have a hardness of JIS (A type) 5 to 100, and the base material to be restored to the original shape may have a hardness of JIS (A type) 25 to 100. In addition, said hardness is the value measured based on JISK-6253.

  For the base material, polymer materials such as acrylic, epoxy, vinyl, silicone, rubber, urethane, methacryl, nylon, bisphenol, diol, polyimide, fluorinated epoxy, fluorinated It is preferable to use various materials such as acrylic. An inorganic material such as quartz or compound glass can also be used.

  For the step of providing the adhesive connecting member on the outer periphery of the substrate, any known method typified by various coating techniques such as spin coating, dip coating and spray coating can be used.

  In addition, the optical transmission medium 21 in the present invention is not limited to a single optical fiber, but may be a tape core or the like in which a plurality of optical fibers are taped, and the number of optical transmission media connected at one time is not limited. When the optical transmission medium 21 is a plurality of optical fibers, the number of adhesive connecting members corresponding to the number of optical fibers is provided, or the adhesive connecting members having a diameter corresponding to the number of optical fibers are previously stored in the mechanical splice. It will be.

  Moreover, as the optical transmission medium 21, a quartz fiber, a plastic fiber, etc. can be used suitably, However, The material is not limited. A photonic crystal fiber such as a holey fiber can also be applied. Moreover, an optical waveguide can be used as the optical transmission medium, and the shape and material thereof can be appropriately selected and used. Furthermore, the refractive index distribution in the optical transmission medium can be appropriately selected depending on the purpose of use, such as a step distribution or a graded distribution.

  In addition, the material used for the holding substrate of the mechanical splice and the V-groove substrate in the present invention is appropriately selected depending on the material of the optical transmission medium to be connected, the required strength and alignment accuracy, but in particular the thermal dimensional change Those made of small plastic, ceramic, metal, etc. are preferably used. As the plastic material, a glassy epoxy material, a crystalline polymer such as PPS (polyphenyl sulfide), PEEK (polyether ether ketone) is preferably used.

  The groove 13 formed in the V-groove substrate 12 of the present invention is not limited to a V shape as long as the optical transmission medium is fixed together with the pressing substrate, and may be a U shape, a semicircle, or a rectangle. These grooves are formed in the same number as the optical transmission media to be connected, and the intermediate optical transmission media are accommodated in each of the grooves.

Next, the optical connection structure of the present invention will be described in more detail using examples.
<Example 1>
First, an acrylic adhesive material having a refractive index adjusted to 1.46 was prepared as a material for the adhesive connection member. This acrylic pressure-sensitive adhesive material is a 30% ethyl acetate solution of n-butyl acrylate / methyl acrylate / acrylic acid / 2-hydroxyethyl methacrylate copolymer (blending weight ratio = 82/15 / 2.7 / 0.3) 100 It is a solution obtained by mixing 1.0 part of Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd., tolylene diisocyanate adduct of trimethylolpropane) with mixing. The viscosity of the solution is about 0.1 Pa · s.

  Then, the solution was discharged from a dispenser (manufactured by Musashi Engineering Co., Ltd., ML606GX) and held in the form of a droplet for several minutes at the tip of the needle to form a sphere. And this was put into 100 degreeC oven for 1.5 hours, the acrylic adhesive material was solidified, and the spherical adhesive connection member was produced. The adhesive strength of the adhesive connecting member was 30 gf / 25 mm, the refractive index was 1.46, the hardness was 25, and the diameter was 100 μm.

  Next, the adhesive connecting member was set in a V groove inside the mechanical splice. Then, using the assembly jig (single core mechanical splice, connecting tool “H”, model number: HOT-HMS-CRC), the holding substrate and the V-groove substrate are fitted into the clamp spring, and the mechanical splice (single core mechanical splice “H”, Model: HOT-HMS-1-125) was assembled.

  Next, two silica-based single-mode optical fibers F2 (manufactured by Sumitomo Electric Industries, outer diameter 0.25 mm, refractive index 1.452 at 20 ° C., length 3.5 m) having an FC connector at one end were prepared. . Then, the end face without the FC connector is mirror-cut with an optical fiber cutter (trade name: “S325A” manufactured by Furukawa Electric Co., Ltd.), inserted from both sides of the mechanical splice, and brought into contact with the adhesive connecting member. The optical connection structure of Example 1 was produced.

<Example 2>
Spherical acrylic beads were used as the substrate. The base material had a refractive index of 1.45, a hardness of 50, and a diameter of 25 μm. The solution was discharged from a dispenser (manufactured by Musashi Engineering Co., Ltd., ML606GX) around the base material and applied to beads to form a spherical shape. Other than that was carried out similarly to Example 1, and produced the optical connection structure of Example 2. FIG. In addition, the adhesive force of the whole adhesive connection member provided with a base material was 30 gf / 25 mm, the refractive index was 1.46, and the diameter was 50 μm (the thickness of the adhesive connection member layer was 12.5 μm).

<Comparative Example 1>
The optical connection structure of Comparative Example 1 was produced in the same manner as Example 1 except that the adhesive connection member was not used.

<Comparative Example 2>
An adhesive connecting member sheet (adhesive strength was 30 gf / 25 mm, refractive index was 1.46, hardness was 25, and film thickness was 20 μm) was prepared in advance. One of the two optical fibers F2 was brought into contact with the adhesive connecting member sheet, and an adhesive connecting member layer was provided at the end portion by pushing and then inserted into the mechanical splice. Otherwise, the optical connection structure of Comparative Example 2 was produced in the same manner as Comparative Example 1. Table 1 shows the main conditions of Examples and Comparative Examples.

<Time required for connection>
First, for the optical connection structures of Examples and Comparative Examples, the time required for connection was measured from the state where the mechanical splice was assembled. Specifically, for Example 1, Example 2, and Comparative Example 1, the time for inserting the optical fiber F2 was measured. For Comparative Example 2, the time for inserting the optical fiber F2 with the adhesive connecting member layer provided at the end was measured. Note that there is a practical problem if the time required for connection is 300 seconds or more.

<Connection loss>
Next, connection loss was evaluated about the optical connection structure of the Example and the comparative example.
[Reference experiment]
First, a reference experiment was performed in order to show a standard state with zero connection loss in the absence of a connection point. FIG. 4 is a circuit diagram of the reference experiment. Reference numeral 100 represents an optical power meter (trade name: OPTICAL MULTI POWER METER “Q8221” manufactured by ADVANTEST), C represents an FC connector, F1 represents a silica-based single mode optical fiber having an FC connector at both ends (manufactured by Sumitomo Electric Industries, FC The optical fiber with connector is 250 μm core wire, and the length is 1 m The optical power meter 100 uses “Q82208” as the sensor unit and “Q81212” as the 1.55 μmL D unit.

  The FC connectors at both ends of the optical fiber F1 were connected to the incident terminal and the emission terminal of the optical power meter 100, respectively. In this state, light having a wavelength of 1550 nm was incident from the incident terminal five times, and the optical power emitted from the emission terminal was measured. And the average value of 5 times was made into the reference value.

[Evaluation of Examples and Comparative Examples]
Next, connection loss was evaluated about the optical connection structure of the Example and the comparative example. FIG. 5 is a circuit diagram of an example and a comparative example. Reference numeral F2 is a quartz single-mode optical fiber having an FC connector at one end.

  First, regarding the optical connection structure of Example 1, two FC connectors were connected to the incident terminal and the emission terminal of the optical power meter 100, respectively. In this state, light having a wavelength of 1550 nm was incident from the incident terminal five times, and the optical power emitted from the emission terminal was measured. And the difference between the average value of 5 times and the reference value was defined as the connection loss of Example 1. Thereafter, the mechanical splice was disassembled using an assembly jig, and the mechanical splice was reassembled and reconnected. In this state, light having a wavelength of 1550 nm is incident from the incident terminal five times, the optical power emitted from the output terminal is measured, and the difference between the average value of the five times and the reference value is determined as the reconnection loss of Example 1. did. The optical connection structures of Example 2, Comparative Example 1 and Comparative Example 2 were similarly evaluated. The connection loss is practically problematic when it is 0.25 dB or more, and particularly excellent when it is less than 0.15 dB. The results are shown in Table 2.

[Evaluation results]
As is apparent from Table 2, the optical connection structures of Example 1 and Example 2 have no practical problems in connection time, connection loss, and reconnection loss, and the connection loss of Example 1 is particularly excellent. . On the other hand, the optical connection structure of Comparative Example 1 has practically no problem with the time required for connection, but there are practical problems with connection loss and reconnection loss. Further, in the optical connection structure of Comparative Example 2, there is no practical problem in connection loss and reconnection loss, but the time required for connection has a practical problem.

It is a perspective view which shows a mechanical splice structure. It is sectional drawing which shows 1st Embodiment of the optical connection structure of this invention. It is sectional drawing which shows 2nd Embodiment of the optical connection structure of this invention. It is a circuit diagram of a reference experiment. It is a circuit diagram of an example and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mechanical splice, 11 ... Holding substrate, 12 ... V-groove substrate, 13 ... Groove,
14 ... Clamp spring, 21 ... Optical transmission medium, 22 ... Covering part, 23 ... Base material,
3 ... Adhesive connection member, 100 ... Optical power meter, C ... FC connector,
F1 ... an optical fiber having FC connectors at both ends,
F2: Optical fiber having an FC connector at one end

Claims (6)

An optical connection structure in which optical transmission media are inserted from both ends of the mechanical splice, and the optical transmission media are optically connected to each other,
The mechanical splice includes a massive adhesive connecting member inside,
Each of the optical transmission media is in contact with and connected to the adhesive connecting member.   The optical connection structure according to claim 1, wherein the massive adhesive connection member includes a base material therein.   The optical connection structure according to claim 1 or 2, wherein the lump-like adhesive connection member has a hardness of JIS (A type) 5 to 100.   The optical connection structure according to claim 1, wherein the massive adhesive connection member is a spherical adhesive connection member. An optical connection method for optically connecting the optical transmission media to each other by inserting optical transmission media from both ends of the mechanical splice,
A lump-like adhesive connecting member is sandwiched inside the mechanical splice,
An optical connection method, wherein the optical transmission medium is inserted from both ends of the mechanical splice and brought into contact with the adhesive connection member.   The optical connection method according to claim 5, wherein the massive adhesive connection member includes a base material therein.

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