JPS59155813A - Reinforcing member of optical fiber connecting part and its reinforcing method - Google Patents

Abstract

PURPOSE:To use repeatedly a reinforcing member by using a reinforcing member made of a shape memory alloy, and executing a reinforcement of an optical fiber connecting part. CONSTITUTION:A reinforcing part and a member of an optical fiber connecting part are shown in the figure. The reinforcing member is formed by a longitudinally divided cylinder 5 made of a shape memory alloy whose reverse transformation temperature Af is lower than a heat resisting temperature of a plastic coating 4 of an optical fiber 2. This cylinder 5 made of a shape memory alloy is made to store a shape so as to become a cylinder whose inside diameter is equal to a core diameter of the optical fiber 2 to be connected. As for the material, a shape memory alloy Ti-Ni is used, and the length of the cylinder 5 is made longer than the length obtained by stripping off the plastic coating of the optical fiber connecting part.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a reinforcing member for an original fiber connection portion and a reinforcing member for this 1i
This invention relates to a reinforcing method using Ii'A members.

As a method for connecting optical fibers, there is a method in which the plastic coatings of two optical fibers to be connected are removed, the end faces of both fibers are butted together, and the fibers are fused by arc discharge or the like.

In this case, in order to maintain the mechanical strength of the original fiber, it is necessary to reinforce the part where the plastic slope is removed after fusion splicing. As one method of reinforcing this connection, a method using a heat shrink tube has been conventionally used. -129805 and Electronics
r,, etters.

vol, 1:5, AI, P-Y2(,19'79
) etc. have been proposed.

1 to 3 are explanatory diagrams of an example of a conventional reinforcing method using a heat-shrinkable tube. First, as shown in FIG. 1, a heat-melting adhesive 8 is inserted into the inside of a heat-shrinkable tube 1 that contracts in the radial direction when heated, along with an optical fiber 2 that is fused and spliced in the longitudinal direction of the heat-shrinkable tube. After that, the joints were reinforced by heating, as shown in FIG. 2 (cross-sectional view after reinforcement) and FIG. 8 (vertical cross-sectional view after reinforcement).

However, in the method of using a heat shrink tube, it is necessary to use a heat shrink tube 1 that is long enough to cover not only the part where the plastic coating 4 of the optical fiber is stripped off, but also the front and back parts of the optical fiber. This heat-shrinkable tube 1 is fixed with a hot-melt adhesive 3, and even after reinforcement, the heat-shrinkable tube 1 remains in the reinforced portion, which has the disadvantage that a difference in diameter occurs before and after the reinforced portion. Furthermore, the diameter of the reinforcement part is Heat IIS! Since it is determined by the balance between the contraction force of the shrink tube 1 and the Young's modulus of the heat shrink tube 1, the hot melt adhesive 8, and the plastic coating 4 of the optical fiber, there is a drawback that the diameter of the reinforcing portion is not necessarily uniform6. To insert the heat-shrinkable tube l, pass it through one of the optical fibers before fusion-splicing the optical fibers, move the heat-shrinkable tube l after fusion-splicing, and apply the heat-melting adhesive 8 to the fusion splice. Since the operation of covering the connection part is performed, there is a drawback that it is difficult to automate the work of reinforcing the optical fiber connection H1.

In order to eliminate these drawbacks, the present invention provides shape description 1. The optical fiber connection part is reinforced using an alloy reinforcing member. The present invention will be explained below with reference to the drawings.

FIG. 4 is a perspective view of an embodiment of the reinforcing member for the optical fiber connection portion of the present invention. The material is shape memory alloy T, )--N
It has a vertically split cylindrical shape whose inner diameter is equal to the diameter of the optical fiber to be connected in the high-temperature phase of -80"C or higher. The length of the cylinder is sufficiently longer than the length of the part of the optical fiber connection part from which the plastic coating is removed.

5 to 9 are explanatory diagrams of a part of the reinforcing method of the present invention using the reinforcing member made of the shape memory alloy of the present invention shown in FIG. 4. First, the shape memory alloy reinforcing member 5 is cooled to a low temperature phase (martensitic phase) of -80"C or less, and expanded into an arc shape as shown in FIG. A 9 am original fiber 2 and a hot-melt adhesive 8 made of a metal ion crosslinked product of ethylene-methacrylic acid copolymer are inserted.

Next, when this is heated to 110"C or more, the shape memory alloy reinforcing member 5 becomes a cylinder with an inner diameter of 0.9 which is memorized in the high temperature phase, and the hot bath adhesive 8 melts and solidifies. 6
As shown in the figure (cross-sectional view during reinforcement) and FIG. 7 (vertical cross-sectional view during reinforcement), the fusion-spliced optical fiber 2 is fixed. Thereafter, shape memory alloy reinforcing member 5 is cooled to a low temperature phase, and as shown in FIG. By removing it from the fiber connection part, as shown in Figure 9 (longitudinal cross-sectional view after reinforcement), it is possible to perform reinforcement so that the diameter of the reinforcement part is the same as the core diameter of the optical fiber and the surface is smooth. did it. The shape memory alloy reinforcing member removed in this manner could be used repeatedly.

FIG. 10 is an explanatory diagram of an embodiment of the reinforcing method of the present invention using two reinforcing members made of the shape memory alloy of the present invention shown in FIG. 4. A shape memory alloy reinforcing member 5 and a shape memory alloy reinforcing member 5' having an inner diameter whose dimensions in the high temperature phase are equal to the outer diameter of the reinforcing member are stacked with the positions of the vertically divided portions of both cylinders shifted from each other. As a result, the reinforcing work could be performed without the hot bath adhesive 3 leaking to the outside of the shape memory alloy reinforcing member 5 during heating and melting.

Next, the 111th Jj is the supplementary tA of the optical 7 eyeper connection part of the present invention.
Fig. 4 is a perspective view of an embodiment of a pond made of gt material, in which a shape memory alloy reinforcing member 6 having the same shape as that in Fig. 4 has a thermoplastic material for reinforcing the optical fiber connection part on the cylindrical side part; A nozzle 7 for injecting resin (not necessarily shape memory alloy) is provided.

12 to 14 are explanatory diagrams of other embodiments of the reinforcing method of the present invention using the reinforcing cylindrical material of the present invention shown in FIG. 11. First, the reinforcing member 6 is cooled down to the low temperature phase, as shown in FIG.
As shown in the cross-sectional view before correction, the optical fiber 2 is expanded into an arc and the fusion spliced optical fiber 2 is inserted inside.

Next, this is heated, and as shown in FIG. 13 (cross-sectional view during reinforcement), after closing the vertically divided cylindrical portion of the reinforcing member 6, polyethylene 8, which is a thermoplastic resin, is injected from the nozzle 7. and harden. Furthermore, by cooling the reinforcing member 6 to a low-temperature phase, expanding it into an arc shape as shown in FIG. 14 (cross-sectional view after reinforcement), and taking out the optical fiber connection part, good reinforcement work can be performed. Ta.

In addition to the above-mentioned 'I'i-Ni alloy, shape memory alloys that can be applied to the reinforcing member of the optical 7-eyeper connection part of the present invention include ou zn A1 alloy, 0u-AI-N
1 alloy, etc., the reverse transformation temperature Af at which the low temperature phase changes to the high temperature phase
Any shape memory alloy may be used as long as the temperature is lower than the heat resistance temperature of the plastic temporary mounting of the optical fiber.

Further, in the above examples, a metal ion cross-linked product of ethylene-methacrylic acid copolymer was used as the hot-melt adhesive, and polyethylene was used as the thermoplastic resin injected from the nozzle, but they are not limited to these. Any hot-melt adhesive or thermoplastic resin can be used as long as it has a lower temperature limit than the plastic coating 2'' of the optical fiber.

As explained above, in the present invention, the reinforcing work of the optical fiber connection part is carried out by the method described below.

In other words, in the high-temperature phase of a shape memory alloy whose inverse transformation temperature Af is lower than the heat resistance grade 7 of the plastic tentative volume of the optical 7 ion fiber, the shape is shaped so that it becomes a cylinder whose inner diameter is equal to the core diameter of the optical fiber to be connected. Using a vertically split cylinder with a memory of The reinforcing member is heated to transform it into a high-temperature phase shape (this is done using a hot-melt adhesive inserted together with the original fiber, or injected from a nozzle provided on a part of the cylindrical side surface of the reinforcing member). The optical fiber is fixed with the thermoplastic resin, and the reinforcing member is subsequently cooled to a low-temperature phase, expanded into an arc, and the optical fiber connection portion is taken out, so that the diameter of the reinforcing portion is the same as the core diameter of the optical fiber. , and has the advantage that the reinforcing member can be reinforced with a smooth surface, and the reinforcing member can be used repeatedly.Also, since it is easy to attach and detach the supplementary member to the optical fiber, it is easy to connect the optical fiber, There is an advantage that the reinforcement work can be easily automated.

[Brief explanation of the drawing]

Figures 1 to 8 are explanatory diagrams of an example of a conventional reinforcing method for an optical fiber connection, in which Figure 1 is a cross-sectional view before reinforcement, and Figures 2 and 8 are respectively FIG. 4 is a cross-sectional view and a vertical cross-sectional view after reinforcement. 4 and 11 are perspective views of embodiments of the reinforcing member of the optical fiber connection section of the present invention, and FIGS. 5 to 9 and 1
Fig. 0 is an explanatory diagram of an embodiment of the reinforcing method using the reinforcing member of the present invention shown in Fig. 4, and Figs. 12 to 14 are illustrations of the implementation of the reinforcing method using the reinforcing member of the present invention shown in Fig. 11. FIG. 5, FIG. 10, and FIG. 12 are cross-sectional views before reinforcement, FIG. 6 and FIG. 18 are cross-sectional views during reinforcement, and FIG.
FIG. 7 is a longitudinal cross-sectional view during reinforcement, FIGS. 8 and 14 are cross-sectional views after reinforcement, and FIG. 9 is a longitudinal cross-sectional view after reinforcement. ■...Heat-shrinkable tube 2...Fusing M-connected optical fiber 3...Heat-melting adhesive 4/Optical fiber plastic MW 5.5', 6...Shape memory alloy vertically split cylinder 7...・・・
Nozzle 8... Thermoplastic resin T... Temperature Af... Jφ transformation temperature of shape memory alloy. Patent applicant: Nippon Telegraph and Telephone Public Corporation Figure 1/ Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 13 Figure 14

Claims (1)

[Claims] The shape memory alloy is made of a shape memory alloy in which the I N variable Fg flow rate Af is lower than the heat resistance temperature of the plastic coating of the optical fiber, and in the high temperature phase O of this shape memory alloy, the inner diameter is the same as that of the optical fiber to be connected. A reinforcing member for a tsuzu fiber connection part, characterized in that it has a vertically split cylindrical shape with a JLF shape memorized so that the cylinder has the same diameter as the core wire. λ In the high temperature phase of the shape memory alloy, where the inverse transformation temperature Af is lower than the heat resistance temperature of the plastic coating of the original fiber, the shape is memorized so that it becomes a cylinder whose inner diameter is equal to the core diameter of the original fiber to be connected. After cooling the vertically split cylinder to the martensitic phase, expanding it into an arc shape, and inserting the optical fiber fusion spliced into the inner (Iff) and the hot bath adhesive,
The reinforcing member is heated to recover the shape of the high rice phase, and the hot bath adhesive is melted and solidified, and then the reinforcing member is cooled to a low wetting phase, spread in an arc shape, and exposed to light. Can it be removed from the fiber connection? Features a method for reinforcing optical fiber connections.