JPH10170747A - Optical fiber connection member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber connection member that prevents air from being mixed with a refractive index matching agent interposed between optical fiber end surfaces. SOLUTION: This member consists of a substrate 1, which has >=1 V groove 1-1 for holding an optical fiber and a top plate 2, and a gap is formed between the V groove substrate 1 and top plate 2 by inserting a wedge, etc., optical fibers are inserted into the V groove 1-1 from both the sides and made to abut against each other, and the wedge is removed to press the top plate 2 against the V groove substrate 1 with the force of a spring material, etc., arranged outside the V groove substrate 1 and top plate 2, thereby fixing the optical fibers inserted into the V groove 1-1 with the V groove 1-1 and top plate 2. In this case, the refractive index matching agent 3 is stuck in the V groove 1-1 prior to the insertion of the optical fibers and not stuck on the top plate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber joining member having a refractive index matching agent on a coupling surface of an optical fiber.

[0002]

2. Description of the Related Art An optical fiber comprises a substrate provided with at least one V-groove for holding an optical fiber and an upper plate, and a gap is formed between the V-groove substrate and the upper plate by inserting a wedge or the like. Is inserted into the V-groove from both sides and abutted, and then the wedge is removed, so that the V-groove substrate and the upper plate are pressed against the V-groove substrate by the force of a spring material or the like arranged outside the upper plate, and the V-groove is formed. A connecting member of a type in which an inserted optical fiber is fixed by a V-groove and an upper plate has been proposed by a name such as a mechanical splice. FIG. 4 shows an example of such a mechanical splice, in which 11 is a substrate having a plurality of V-grooves 11-1, 12 is an upper plate, 13 is a spring member for applying a pressing force between the substrate and the upper plate, and 14 is a spring member. The wedge is. (A) Wedge 1
FIG. 4B shows a view before inserting a wedge between the substrate and the upper plate, and FIG. 4B shows a view when a wedge is inserted. In this type of connecting member,
In many cases, the end face of an optical fiber is used while being cut by cleavage, and the optical fiber is simply butted in the axial direction without applying a pressing force. In order to obtain the return loss, a refractive index matching agent is usually interposed on the abutting surface of the optical fiber.

[0003]

As shown in FIG. 2, the refractive index matching agent 4 has a V
It is applied so that it is almost filled in the groove 1-1, and is put in.
When the optical fiber is inserted from both sides of the V-groove by separating the groove substrate 1 and the upper plate 2 with a wedge or the like, the optical fiber adheres to the end face of the optical fiber and is pushed in, and is interposed between the end faces of the butted optical fibers. It has become. However, when a gap is formed between the V-groove substrate and the upper plate by a wedge or the like, the refractive index matching agent is divided into a portion attached to the V groove and a portion attached to the upper plate, and the refractive index matching agent is included in the refractive index matching agent. It is easy for air to be entrained. The air moves to the end face of the optical fiber when the optical fiber is inserted and butted, and intervenes between the butted end faces of the optical fiber together with the refractive index matching agent. When the optical fiber connected by such a connecting member receives a temperature change of the outside air or the like, the air between the end faces moves and appears as a connection loss or a return loss of the optical fiber, and the reliability of the optical fiber line is reduced. Is lost. The present invention provides a connecting member that prevents such air from getting into the refractive index matching agent.

[0004]

According to the present invention, a substrate having one or more V-grooves for holding an optical fiber and an upper plate are provided, and a wedge or the like is inserted between the V-groove substrate and the upper plate. By forming a gap, the optical fiber is inserted into the V-groove from both sides and abutted, and then the wedge is removed, so that the V-groove substrate and the V-groove are moved by the force of a spring material or the like disposed outside the upper plate. In a connecting member of a type in which the optical fiber inserted into the V-groove is fixed to the V-groove and the upper plate by pressing against the substrate, a refractive index matching agent is previously attached to the V-groove prior to insertion of the optical fiber, and It is characterized in that the rate matching agent does not adhere to the upper plate. If the amount of the refractive index matching agent is in the range of 20 to 80% with respect to the cross section of the V-groove in the vicinity of the center of the V-groove in the longitudinal direction, when the distance between the substrate and the upper plate is enlarged, the index matching with the upper plate is performed. A sufficient amount of the refractive index matching agent can be easily attached to the end face of the optical fiber inserted into the V-groove while preventing the agent from attaching.

[0005]

FIG. 1 is a view showing an embodiment of an optical connecting member according to the present invention. In the figure, 1 is a plurality of V-grooves 1-1
And 2 is an upper plate. Reference numeral 3 denotes a refractive index matching agent applied inside the V groove. Refractive index matching agent 3
Is applied so as not to adhere to the upper plate 2. The refractive index matching agent does not need to be applied over the entire length of the V-groove in the longitudinal direction. It is sufficient if the refractive index matching agent is applied only to the abutting position of the optical fibers inserted into the V-groove from both sides, that is, only near the center of the V-groove. It is. If the refractive index matching agent is applied to the inside of the V-groove in this way, the gap between the V-groove substrate and the upper plate is enlarged by inserting a wedge, and when the optical fiber is inserted from both sides of the V-groove and butted, The refractive index matching agent in the V-groove is pushed in by the end face of the optical fiber and adheres to the entire end face of the optical fiber, and only the refractive index matching agent adheres between the end faces of the butted optical fibers. No air is trapped inside.

When the optical fiber 5 is inserted as shown in FIG. 3 near the longitudinal center of the V-groove where the optical fiber is abutted, the refractive index matching agent is attached by the end face of the optical fiber. Since it is necessary to be pushed into the optical fiber abutting surface and adhere to the entire end surface, 6 in FIG.
(When the V-groove is a regular triangle, the area of 6 is 14% of the V-groove area). Taking a little margin, 20% or more is preferable. In addition, if the refractive index matching agent is attached to the V-groove, if it rises even slightly from the V-groove, it may adhere to the upper plate.
It is desirable to suppress the groove area to 80% or less. Note that the amounts of these refractive index matching agents are values near the center of the V groove where the optical fibers are butted, and need not cover the entire length of the V groove.

As a material of the V-groove substrate and the upper plate, an injection molded body of a functional plastic such as a liquid crystal polymer, a polycarbonate or the like or a metal is used. Silicon grease or the like having a refractive index close to that of glass is used as the refractive index matching agent. In addition, as a refractive index matching agent, JI
If silicon grease having a “consistency” of about 300 specified in SK 2220 is used, the refractive index matching agent in the V-groove does not flow out due to vibrations due to handling and adhere to the upper plate.

[0008]

According to the present invention, in a connecting member consisting of a substrate provided with at least one V-groove for holding an optical fiber and an upper plate, a refractive index matching agent is previously attached to the V-groove prior to insertion of the optical fiber. Since the refractive index matching agent is not attached to the upper plate, even when the space between the V-groove substrate and the upper plate is opened for inserting an optical fiber, the refractive index matching agent is applied to the upper plate. Does not adhere, the air is not entrapped in the refractive index matching agent due to the separation of the refractive index matching agent, and the connection loss does not change or the return loss does not change when the connection member is used for a long time. A highly reliable connection member can be realized.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a connecting member of the present invention.

FIG. 2 is a view showing a connection member according to the related art.

FIG. 3 is a diagram for explaining an amount of a refractive index matching agent in a connection member of the present invention.

FIG. 4 is a view showing an example of a mechanical splice according to the related art, in which (A) shows a state before a wedge is inserted,
(B) shows the state when the wedge is inserted.

[Explanation of symbols]

 1: V-groove substrate 1-1: V-groove 2: upper plate 3, 4: refractive index matching agent

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshiaki Kakii 1-chome, Taya-cho, Sakae-ku, Yokohama, Kanagawa Prefecture Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Masaaki Takaya 3-2-2 Nishishinjuku, Shinjuku-ku, Tokyo No. Nippon Telegraph and Telephone Corporation (72) Inventor Shinji Nagasawa 3-20-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (2)

[Claims] 1. An optical fiber comprising a substrate having at least one V-groove for holding an optical fiber and an upper plate, and a gap formed between the V-groove substrate and the upper plate by inserting a wedge or the like. Is inserted into the V-groove from both sides and abutted, and then the wedge is removed, so that the V-groove substrate and the upper plate are pressed against the V-groove substrate by the force of a spring material or the like arranged outside the upper plate, and the V-groove is formed. In the connecting member of the type in which the inserted optical fiber is fixed with the V-groove and the upper plate, a refractive index matching agent is previously attached to the V-groove before inserting the optical fiber, and the refractive index matching agent is attached to the upper plate. An optical fiber connecting member not attached. 2. The optical fiber connecting member according to claim 1, wherein the amount of the refractive index matching agent is 20 to 80% with respect to the V-groove cross-sectional area near the center in the longitudinal direction of the V-groove.