JPH055523Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is an optical connector that prevents local bending deformation of the optical fiber core wire by retracting the ferrule when connecting the optical connector. Regarding the improvement of

Optical fibers are constructed into easy-to-handle optical fiber cords and are often used in optical communication equipment, optical measurement equipment, etc., but in order to detachably connect the end of this optical fiber to equipment etc. A connector is required.

[Conventional technology]

FIG. 2 is a sectional view of this type of conventional optical connector.

The optical fiber cord 3 consists of an optical fiber core 2 at the center, a Kevlar (trade name) 4 made of a reinforcing fiber material longitudinally attached to the periphery of the optical fiber core 2, and a comparative material that protects the periphery. and an outer resin coating layer of flexible synthetic resin. Optical fiber core 2
consists of a glass core wire consisting of a core portion that transmits optical signals in the center, a cladding layer integrally formed around the core portion, and a protective resin coating layer surrounding the core portion.

The procedure for attaching an optical connector to the end of such an optical fiber cord will be described. Referring to FIG. 2, a cap nut 3 is inserted into the optical fiber cord 3 in advance. Next, a predetermined length of the outer resin coating layer at the end of the optical fiber cord 3 is cut off, the optical fiber core 2 is pulled out, and its tip is fitted into the center hole of the ferrule 1, and both are adhesively fixed.

The Kevlar 4 on the outside of the optical fiber core wire is adhered to the outer periphery of a cylindrical support fitting 6 made of stainless steel or the like, which has been inserted in advance, as shown. On the other hand, the ferrule 1 is elastically biased toward its tip by the coiled spring 5 interposed between the support metal fitting 6 and the ferrule 1. A presser metal fitting 7 having a brim-like ring portion is inserted into the inside of the ferrule 1 from the tip thereof, and is screwed into the support metal fitting 6 and screwed into contact with the ring portion to define the position of the ferrule 1.

The cap nut 8 inserted into the optical fiber cord 3 is placed in a position where it comes into contact with the stepped portion of the support fitting 6,
A reinforcing member 9 made of an elastic material such as high-quality synthetic rubber is placed over the support fitting 6 to which the Kevlar 4 is adhered and the optical fiber cord 3.

[Problem that the invention attempts to solve]

FIG. 3 is a diagram for explaining the state in which the optical fiber core undergoes local bending deformation due to buckling. It is a front view, and the same parts as in FIG. 2 are given the same reference numerals.

In the optical connector having the configuration shown in FIG. 2, a force in the direction of arrow T is applied by a coil spring 5 to the ferrule 1 of the optical connector, but since the position is defined by the presser metal fitting 7, the optical fiber is centered. Line 2 is the stretched normal state.

When an optical connector is connected to another similar optical connector through an adapter (both not shown) in a facing state, a force in the direction of arrow P acts on the ferrule 1 of the optical connector, and both ferrules 1 The optical fibers are moved back by a small distance ε in the direction of arrow A (shown in FIG. 3b) against the elastic force of the coil spring 5, and the restoring force of the coil spring 5 brings the end surfaces of the optical fibers into close contact with each other. Optical coupling is achieved at the part.

A protective coating layer made of resin is formed on the portion of the optical fiber core wire 2 that has been pulled out. Due to manufacturing reasons, the thickness of this protective coating layer is not ideally uniform, and as a result, compressive stress due to the retreat of the ferrule is concentrated in areas where the thickness is thin or uneven, as shown in Figure 3b. As shown in the figure, that part is locally bent and deformed, and is in a buckled state that can be restored without destruction.

For optical connectors with the above conventional configuration,
The optical fiber core wire 2 in the optical connector is connected to a coiled spring 5,
When the connectors are not connected to each other, they are always maintained in a normal (straight line) state by the presser metal fittings 7, but when the connectors are connected, a pressing force P acts against the elastic force of the coiled spring 5. As a result of the above-mentioned receding, local bending deformation occurs in a certain part of the optical fiber, resulting in a transmission loss of the optical signal being transmitted in this part. This is a very troublesome problem because it changes each time the connection is made or depending on the bending of the optical fiber cord.

[Means for solving problems]

The present invention aims to solve the above-mentioned problems, and the means for achieving this purpose consists of an optical fiber cord and an optical fiber drawn out from inside the optical fiber cord at the end of the optical fiber cord. A fiber core, a ferrule attached to the tip of the optical fiber, a spring that elastically biases the ferrule toward the tip, and a spring with the tip approaching the rear of the ferrule to move the optical fiber. A pipe for preventing buckling deformation of the optical fiber core inserted into the inside and having an inner diameter slightly larger than the outer diameter of the optical fiber core inserted in the outer sheath of the optical fiber cord at the rear end thereof. , when the optical connector is connected, the ferrule is configured so that the optical fiber core inside the pipe does not undergo local bending deformation as the ferrule slightly retreats against the urging force of the spring; Yes, this configuration achieves the objective.

[Effect]

In the above-mentioned optical connector, a pipe for preventing buckling deformation is fitted into the optical fiber core wire portion within the optical connector, and the gap between the outer circumferential surface of the optical fiber and the inner circumferential surface of the pipe is appropriately narrow. Therefore, even if a situation occurs in which the optical fiber core wire undergoes local bending deformation, it is restricted to the inner surface of the pipe and is prevented from causing local bending deformation. Alternatively, the entire optical fiber may be retracted in a straightened form, or it may be in a combination of these forms, so that no optical transmission loss occurs.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the optical connector according to the present invention will be described in detail by way of examples with reference to the drawings.

FIG. 1 is a sectional view of an embodiment of an optical connector according to the present invention. In FIG. 1, the optical connector of the present invention is similar to FIG. 2: a ferrule 1, an optical fiber core 2, an optical fiber cord 3, a Kevlar 4, a coiled spring 5, a support fitting 6, a holding fitting 7, a cap nut 8,
Since the reinforcing member 9 is provided, a description of these parts will be omitted, but please refer to the above-mentioned explanatory part of FIG. 2 for a thorough understanding.

In FIG. 1, the buckling deformation prevention pipe 10 through which the optical fiber core 2 is inserted is a metal pipe made of stainless steel or the like, and its inner diameter is slightly larger than the outer diameter of the optical fiber core 2. It is set to diameter. Although the tip of the pipe 10 is close to the rear of the ferrule 1, it is set at a positional interval that sufficiently avoids the distance ε that the ferrule 1 moves back due to connector connection. In addition, the rear part is an optical fiber cord 3
It is inserted into the outer jacket of the Kevlar 4, especially the inner surface of the Kevlar 4.

With the above configuration, by connecting to another similar optical connector (not shown) via the adapter in a facing state, the ferrule 1 is retracted by the distance ε in the same manner as described above. However, even if the optical fiber core wire 2 were to undergo local bending deformation as in the prior art, the deformation would not occur because it is surrounded by the pipe 10. Therefore, the optical fiber core wire 2 is allowed to be deformed and curved by an amount limited by the gap formed between it and the pipe 10, which is a curved state with a small curvature and a large radius. Further retreat amount is
Although it is slid and pushed into the Kevlar 4 inside the optical fiber cord 3, this amount is extremely small.

The pipe 10 is not limited to stainless steel, but may be made of other metals, such as nickel-plated brass pipe, without any problems.

[Effect of idea]

As is clear from the above description, according to the optical connector according to the present invention, local bending deformation of the optical fiber core wire caused by the retreat of the ferrule due to the pressing force generated when optical connectors are connected can be prevented. This has an extremely large practical effect of preventing transmission loss of optical signals due to deformation of the optical fiber. In view of the problems of the prior art, the inventors of the present invention actually produced a prototype of the present invention and confirmed its effectiveness.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an embodiment of the optical connector according to the present invention, Fig. 2 is a sectional view of a conventional optical connector, and Fig. 3 is a state in which the optical fiber core undergoes local bending deformation due to buckling. This is a diagram for explaining a.
The figure is a front view of the normal state, and the figure B is a front view of the bent state. Throughout the diagram, the symbols in the diagram are 1, ferrule, and 2.
is an optical fiber core wire, 3 is an optical fiber cord, 4 is Kevlar, 5 is a coiled spring, 6 is a support metal fitting, 7 is a holding metal fitting, 8 is a cap nut, 9 is a reinforcing member, and 10 is a pipe for preventing buckling. Each is shown below.

Claims (1)

[Scope of utility model registration request] An optical fiber cord, an optical fiber core drawn out from inside the optical fiber cord at an end thereof, a ferrule attached to the tip of the optical fiber core, and elastic biasing of the ferrule toward the tip. a spring whose tip approaches the rear of the ferrule and into which the optical fiber is inserted; and a pipe for preventing buckling deformation of the optical fiber core wire having an inner diameter of An optical connector characterized in that the fiber core wire is configured so that local bending deformation does not occur.