JPS6238684B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an optical fiber terminal structure such as an optical connector, and particularly to an optical fiber terminal structure in which two fiber core wires are inserted into the axial hole of a ferrule. Regarding.

In an optical transmission system, in addition to an optical fiber serving as a main signal line, another optical fiber may be laid in parallel as a fault detection line. This fault detection line is connected to the same light receiving element as that connected to the main signal line in the optical connector section in the repeater.

Therefore, in the ferrule of a connector or the like used in this way, two optical fibers are inserted in parallel into the same axial hole.

[Prior Art] As described above, the conventional optical fiber terminal structure in which two optical fibers are attached is configured as shown in the side sectional view in FIG. 3a and the axis-perpendicular sectional view in FIG. .

That is, the lens 8 is attached to the front of the light receiving element 9,
Light from two optical fibers 5A and 5B inserted in parallel to the ferrule 1 is projected onto the lens 8.

On the other hand, the optical fiber 5A and the optical fiber 5B have the same shape, and the fiber core wire 6A of the optical fiber 5A and the fiber core wire 6B of the optical fiber 5B also have the same diameter.

A cylindrical ferrule 1 made of ceramics (for example, alumina) has an axial hole 2 formed at the axial center on the lens 8 side, and a large coaxial hole 2 is formed on the opposite side from the axial hole 2. A diameter hole 3 is provided, and the axial hole 2 and the large diameter hole 3 are connected through a tapered hole.

The inner diameter of the axial hole 2 is slightly larger than twice the outer diameter of the fiber core wire 6A, and has a dimension that allows the fiber core wire 6A and the fiber core wire 6B to be inserted in parallel.

Further, the inner diameter of the large-diameter hole 3 is sufficiently larger than twice the outer diameter of the covering portion of the optical fiber 5A, and has a dimension that allows the optical fiber 5A and the optical fiber 5B to be loosely inserted in parallel.

After inserting the fiber core wire 6A and the fiber core wire 6B in parallel into the axial center hole 2 of the ferrule 1, and inserting the covering portions of the optical fibers 5A and 5B into the large diameter hole 3, adhesive ( For example, it is fixed with epoxy resin) 7.

Therefore, the fiber core wire 6A and the fiber core wire 6B
are completely parallel to each other within the axial hole 2, and are efficiently projected onto the light receiving element 9 via the lens 8.

[Problem that the invention seeks to solve]

However, in the conventional optical fiber terminal structure described above, during assembly, one fiber core wire is first inserted into the shaft center hole, and then the other fiber core wire is inserted into the shaft center hole. Therefore, there is a problem in that the second fiber core wire is rubbed by the hard ceramic diaphragm corner 4, causing scratches and breakage.

[Means for solving problems]

The above problem is that a large diameter hole is formed in which the fiber core wires of the two optical fibers are connected to the axial hole into which the fiber core wires are inserted in parallel, and the coated portions of the two optical fibers are inserted in parallel and fixed with adhesive. A state in which the two fiber core wires are inserted into the sleeve, and the sleeve is made of a material having an inner diameter equal to or slightly larger than the inner diameter of the axial center hole and has a lower hardness than the ferrule. This problem is solved by the optical fiber terminal structure of the present invention, in which the sleeve is inserted and fixed into the connecting portion between the large-diameter hole and the axial hole.

[Effect]

According to the above means of the present invention, by first inserting two fiber core wires in parallel into the sleeve,
The sleeves make them almost completely parallel. Therefore, when inserting into the shaft center hole, there is no risk of rubbing against the aperture corner.

Furthermore, since the sleeve has sufficiently lower hardness than the fiber core wire, no scratches will occur even if the fiber core wire is rubbed at the corner of the hole when inserted into the sleeve.

That is, the above problem is eliminated.

〔Example〕

The gist of the present invention will be specifically explained below with reference to embodiments shown in FIGS. 1 and 2. Note that the same reference numerals indicate the same objects throughout the figures.

FIG. 1 is a side sectional view of one embodiment of the present invention, and b
is a sectional view perpendicular to the axis, and FIG. 2 is a side sectional view of another embodiment.

In FIG. 1, 10 is a sleeve made of a material having sufficiently lower hardness than the fiber core wire 6A (the fiber core wire 6B is also made of the same material), for example, a synthetic resin such as nylon or vinyl.

The inner diameter of the sleeve 10 is equal to or slightly larger than the inner diameter of the axial center hole 2, the outer diameter is sufficiently smaller than the inner diameter of the large diameter hole 3, and the length is equal to or slightly larger than the inner diameter of the large diameter hole 3.
is much shorter (for example, by a quarter) than the length of

Moreover, one end surface side of the hollow hole of the sleeve 10 is
The opening is tapered to facilitate insertion of the fiber core.

In order to insert the optical fibers 5A and 5B into the ferrule 1 in parallel using such a sleeve 10, first insert one fiber core wire 6A.
is inserted into and passed through the hollow hole of the sleeve 10. Next, the other fiber core wire 6B is inserted and penetrated.

As a result, the fiber core wire 6A and the fiber core wire 6B circumscribe each other and inscribe the hollow hole, so that they are parallel to each other.

After inserting the fiber core wires of the two optical fibers 5A and 5B into the sleeve 10 in this way, the sleeve 10 is inserted into the large diameter hole 3 of the ferrule 1, and the connecting portion between the axial center hole 2 and the large diameter hole 3 is inserted. and insert the fiber core wire and the fiber core wire 6B into the shaft center hole 2. Then, the axial center hole 2 and the large diameter hole 3 are filled with adhesive 7, and the optical fiber 5A, the coating portion of the optical fiber 5B, the fiber core wire 6A, the fiber core wire 6B, and the sleeve 10 are fixed to the ferrule 1.

In FIG. 2, the large diameter hole 3 of the ferrule 1 is
is a stepped hole, and a stepped hole portion 3A is provided at the connection portion between the large-diameter hole 3 and the axial hole 2.

Reference numeral 11 denotes a sleeve made of a material whose hardness is sufficiently lower than that of the fiber core wire 6A (the fiber core wire 6B is also made of the same material), such as a synthetic resin such as nylon or vinyl.

The inner diameter of the sleeve 11 is equal to or slightly larger than the inner diameter of the shaft hole 2, and the outer diameter is equal to or slightly larger than the inner diameter of the stepped hole 3.
It is slightly smaller than the inner diameter of A and is fitted into the step hole 3A.

Moreover, one end surface side of the hollow hole of the sleeve 11 is
The opening is tapered to facilitate insertion of the fiber core.

Therefore, when the fiber core wire 6A and the fiber core wire 6B are inserted into the hollow hole of the sleeve 11 with the sleeve 11 inserted into the step hole 3A, the aperture corner 4
They are inserted in parallel into the shaft center hole 2 without rubbing against each other.

After that, the adhesive 7 is filled into the axial hole 2, the large diameter hole 3, and the step hole 3A, and the optical fiber 5A, the coating of the optical fiber 5B, the fiber core wire 6A, the fiber core wire 6B, and the sleeve 11 are attached to the ferrule 1. stick.

〔Effect of the invention〕

As explained above, the present invention has practical advantages such as that when two optical fibers are inserted into the axial center hole of a ferrule, there is no fear that the fiber core wires will break, and that it is easy to insert the fiber wires. It has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of one embodiment of the present invention;
b is a cross-sectional view perpendicular to the axis, FIG. 2 is a side sectional view of another embodiment, and FIG. 3 is a diagram of a conventional optical fiber terminal structure.
is a side sectional view, and b is an axis-perpendicular sectional view. In the figure, 1 is a ferrule, 2 is an axial hole, and 3 is a ferrule.
is a large diameter hole, 3A is a stepped hole, 3A is a stepped hole, 4 is an aperture corner, 5A, 5B are optical fibers, 6A, 6B
1 is a fiber core wire, 7 is an adhesive, 8 is a lens, 9 is a light receiving element, and 10 and 11 are sleeves.

Claims (1)

[Claims] 1. A ferrule in which a large-diameter hole is formed in which the fiber core wires of two optical fibers are inserted in parallel to each other, and the coated portions of the two optical fibers are inserted in parallel and fixed with adhesive. , a sleeve formed of a material with a lower hardness than the ferrule and having an inner diameter equal to or slightly larger than the inner diameter of the axial center hole, and with the two fiber core wires inserted into the sleeve, the sleeve An optical fiber terminal structure characterized in that a is inserted and fixed into a connecting portion between the large-diameter hole and the axial hole.