JPH0725765Y2 - Optical connector terminal structure for small diameter core wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to an optical fiber connector, and more particularly to an optical connector terminal structure for a small-diameter optical fiber core wire.

[Conventional technology]

Usually, when optical fibers are detachably connected via an optical connector, the optical fiber to be coupled to the optical connector has a tension-resistant member inside and a diameter of 2-3 m.
A so-called optical fiber cord of about m is used. However, recently, in order to improve the packaging density and downsize the equipment, there is an increasing demand for mounting an optical connector directly on an optical fiber core wire without a jacket. At first, the core wire diameter was about 0.9 mm, but recently, there has been a demand to attach an optical connector to the core wire having a diameter of 0.25 mm, which is even thinner.

Conventionally, as shown in FIG. 2, the terminal structure of this type of optical connector for a small-diameter core wire is provided with a small-diameter hole slightly thicker than the outer diameter of the optical-fiber core wire 3 at the rear part of the ferrule 1 to form an optical fiber. The core wire 3 was fixed by adhesion. Alternatively, as shown in FIG. 3, a considerably thick core wire fixing hole is provided in the rear portion of the ferrule 1 ', and a large amount of adhesive is filled in the hole to fix the core wire.

[Problems to be solved by the device]

In order to realize this conventional terminal structure (FIG. 2), it is necessary to open a thin hole of about 0.25 mm for inserting the optical fiber core wire into the ferrule over a length of several mm. However, since the ferrule is made of metal or ceramic, it is difficult to form a small-diameter hole, which is extremely expensive.

On the other hand, as shown in FIG. 3, in the case of a structure in which a hole having a large diameter is filled with an adhesive to fix the optical fiber core wire, the adhesive layer becomes too thick. As a result, there is a drawback that excessive stress is generated due to expansion when the adhesive is cured, microbending occurs in the optical fiber, and adhesive loss of the optical connector increases.

[Means for Solving the Problems]

For the optical connector of the present invention, the ferrule core holding part has a diameter of 0.9 to 1 mm, which is larger than the conventional one, and the inner diameter is 0.25 mm.
The thin core part is fixed to the ferrule via a glass tube that is slightly thicker and has an outer diameter slightly smaller than the inner diameter of the rear part of the ferrule.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an optical connector terminal structure according to an embodiment of the present invention.

In the figure, in the rear part of the ferrule 1, a hole having a diameter of about 0.9 to 1 mm is provided on the central axis, like the conventional ferrule shown in FIG. The hole has an outer diameter slightly smaller than the inner diameter of the rear hole of the ferrule 1 and slightly larger than the optical fiber core wire 3 to be fixed, that is, an inner diameter of about 0.27 to 0.3 mm. A transparent hollow cylindrical glass tube 2 is inserted, and a thin optical fiber core wire 3 is fixed in the hollow hole of the glass tube. Glass tube 2
Are easily formed by the drawing method. Glass tube 2
The fixing of the ferrule 1 and the fixing of the glass tube 2 and the optical fiber core wire 3 are performed with the adhesive 4. However, in the embodiment of the present invention, it is also possible to use an ultraviolet curing resin having a short curing time. is there.

In the front part of the ferrule 1, a hole for fixing an element wire made of a core and a clad of the optical fiber core wire 3 is formed on the central axis.

[Effect of device]

As described above, the present invention has a structure in which the optical fiber core wire having a small diameter of 0.25 mm is fixed to the hole provided in the rear portion on the center axis of the ferrule via the glass tube, so that the 0.25 mm is directly attached to the ferrule. You don't have to drill a thin hole in. Since the glass tube is manufactured by a manufacturing method called a drawing method, it is easy to provide a thin through hole, and therefore, the optical connector terminal portion of this structure has an effect that it can be realized at a very low price.

Also, in the rear part of the ferrule, the optical connector terminal part of this structure is not filled with adhesive in an unnecessarily large amount.Therefore, when the adhesive is hardened, microbending occurs in the optical fiber due to the expansion force of the adhesive and the connection This has the effect of avoiding the problem of increased loss.

In addition, since the glass tube has a property of transmitting ultraviolet rays, the optical fiber core wire and the glass tube can be fixed to the rear part of the ferrule by using an ultraviolet curable resin, so that there is an effect that the assembly work time can be shortened.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIGS. 2 and 3 are sectional views of a conventional optical connector terminal structure. 1 ... Ferrule, 2 ... Glass tube, 3 ... Optical fiber core wire, 4 ... Connection agent.

Claims (2)

[Scope of utility model registration request] 1. An optical fiber core wire comprising a core and a clad, an optical fiber core wire having a coating portion for covering the optical fiber wire except a tip portion of the optical fiber wire, and the optical fiber core wire. Has an inner diameter slightly larger than
A glass tube fitted and fixed to the coating portion of the optical fiber core wire, and a first hole having an inner diameter slightly larger than the outer diameter of the optical fiber element wire near the tip portion, and the glass The second hole having an inner diameter slightly larger than the outer diameter of the tube is provided at the end portion, and the end surface of the glass tube is projected outward from the end portion so that the first hole and the optical fiber element An optical connector terminal structure for a thin core wire, comprising: a wire, the glass tube, and a ferrule to which the second hole is fixed. 2. The utility model registration wherein the first hole of the ferrule, the optical fiber element wire, the glass tube, and the second hole are fixed to each other with an adhesive.
The optical connector terminal structure for a small-diameter core wire according to the item.