JPS6296913A - Method for manufacturing optical connector having spherical part - Google Patents

Abstract

PURPOSE:To form a spherical surface of good quality having an optional radius of curvature in a very short time by fusing a projected part of a sleeve, which is projected to an aperture part and to which a fiber is inserted, by heating. CONSTITUTION:A sleeve 21 is fitted to a sleeve guide 12, and its front end part is projected a length (h) to an aperture part 11. The front end part of a fiber 22 coincides with that of the sleeve 21, and a coating 23 coating the fiber 22 is in a fiber guide 13. A heat shielding plate 30 is provided which covers a part other than the aperture part 11 of a ferrule to prevent this part from being heated by a microtorch 35. The sleeve 21 and the fiber 22 consist of materials having the same melting point practically such as a quartz; and when they are heated by the microtorch 35, they are fused and a spherical surface 29 is formed by the surface tension after fusion. The length (h) by which front end parts of the sleeve 21 and the fiber 22 are projected from the aperture part is changed to set the radius of curvature of the spherical surface 29 to an optional value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in optical connectors, and more particularly to optical connectors with spherical joint ends.

[Prior Art] In optical connectors used for optical communications, coupling between optical connectors is an important issue. That is, the aim is to reduce connection loss at the connection point of the optical connector and to reduce reflected light due to Fresnel reflection at the connection point. In order to solve this problem, if the abutting end surfaces of both optical connectors are made convex and connected, an extremely good connection with low connection loss and little Fresnel reflection can be obtained.

In order to obtain such a convex spherical end face, a method of polishing the end face has been used.Reference 1: [Convex spherical polished optical connector] 1985, IEICE General Conference, No. 2
606, Document 2: "About a method of end face polishing of low-loss optical connectors," 1985, National Conference of the Institute of Electronics and Communication Engineers, No. 2607).

[Problems to be Solved by the Invention] If such a method of polishing a convex spherical surface is used, the process cannot be completed in a short time, so an increase in the cost of manufacturing the optical connector cannot be avoided. This has been a major problem in using such optical connectors with good performance.

[Means for solving the problem] In order to solve this problem, for example, a quartz fiber covered with a quartz sleeve is heated and melted with a microtorch at the tip of the ferrule of an optical connector. , a method was adopted in which a spherical surface was formed at the tip using the surface tension of molten quartz.

[Function] As a result, a high-quality spherical surface with an arbitrarily large radius of curvature can be formed in an extremely short period of time, and since the sleeve and fiber are integrated by melting, there is no need to use adhesive, so the characteristics are extremely high. Stable products can now be realized at low cost.

[Example] An embodiment of the present invention is shown in FIG. 1 and will be described.

FIG. 1(a) shows a cross-sectional view of the mating part of the optical connector, where 10 is the ferrule of the optical connector, 11 is the opening of the ferrule 10, and 12 is the sleeve with a deep hole following the opening 11. 13 is a fiber guide following the sleeve guide 12. 21 is a quartz sleeve, for example, which is fitted into the sleeve guide 12 and whose tip protrudes into the opening 11 by a length h. 22 is a quartz fiber, for example, and its tip is located inside the sleeve 21 so as to match the tip of the sleeve 21. 23 is a coating that covers the fiber 22 and is inside the fiber guide. A heat shield plate 30 covers the ferrule other than the opening 11 to prevent it from being heated by the microtorch 35, and heats and melts only the sleeve 21 and the tip of the fiber 22.

The sleeve 21 and the fiber 22 are made of, for example, quartz (or multi-component glass) having substantially the same melting point, and when heated by the microtorch 35, they melt and their surface tension creates a cross-sectional shape after melting. Figure 1 (b
) A spherical surface 29 is formed as shown in FIG.

Here, if the diameter of the sleeve 21 is 2a, then the sleeve 2
If the length h of 1 protruding into the opening 11 is sufficiently smaller than 2a, the height X of the spherical portion 29 will be approximately equal to 2h.

Therefore, by changing the length h in which the tips of the sleeve 21 and the fiber 22 protrude into the opening, the radius of curvature of the spherical portion 29 can also be set to an arbitrary value. Since the sleeve 21 and the tip of the fiber 22 are molten, the prior art (Reference 3; "Characteristics of optical connectors with soldered fibers", 1985 IEICE Comprehensive National Conference No. 2)
608>, there is no need for processes such as soldering,
The man-hours can also be omitted, and sufficient strength can be obtained even when the fiber 22 is pulled to the right in the drawing.

FIG. 2 is a diagram illustrating another embodiment of the present invention.
In the cross-sectional view corresponding to b), a step is provided in the sleeve guide 12 at a depth d from the opening 11, and a spherical portion 29 is formed by melting the sleeve 21 and the tip of the fiber 22 that fit into the step. This is what I did.

In FIG. 1, the position of the right end of the sleeve 21 in the drawing determines the accuracy of the protrusion length h of the sleeve 21 depending on the depth of the sleeve guide 12, and this depends on the accuracy of the radius of curvature of the spherical portion 29. This will determine the

Therefore, as shown in FIG. 2, by making the depth d from the bottom of the opening 11 to the step of the sleeve guide 12 short, the accuracy of this depth d can be easily increased, and the fiber The sleeve 21 is supported by this step to counteract the force that causes the sleeve 22 to be pulled rightward in the drawing.

When connecting an optical connector having a spherical surface 29, the vertices of the spherical surface are generally connected, but as shown in FIG. ) may be provided for connection.

In such a case, the depth of the opening 11 may be increased to obtain the gap q. In this way the gap q
Being able to connect with a gap in between prevents damage to the apex of the spherical portion due to repeated connections, and is advantageous for rotary connectors that can rotate.

The following describes the tendency of the relationship between the gap g9 loss when the spherical portion 29 has a small radius of curvature, when the radius of curvature of the spherical portion 29 is large, and when the end face of the fiber 22 is flat when connecting with a gap q@ in this way. 4A,B.

Shown in Figure 0.

Among these figures, as is clear from FIG. 4B in particular, the gap range in which the loss is low can be taken wider than in the cases of FIGS. 4A and 4C. Therefore, as shown in FIG. 4B, the tip of the fiber 22 is connected to a spherical portion 2 with a large radius of curvature.
If it is set to 9, it is possible to realize a connection with relatively low loss without requiring high accuracy such as setting the gap q to zero.

In addition, in FIG. 1(b) or FIG. 2, the opening 1
1 and the top of the spherical part 29 substantially coincide with each other. However, as described above, the top of the spherical part 29 may protrude in front of the front of the opening 11. It will be clear from the explanation.

[Effects of the Invention] As is clear from the above description, according to the present invention, a convex spherical surface having an arbitrarily large radius of curvature can be formed at the tip of an optical connector in a very short time, and the gap between the sleeve and the fiber can be formed in a very short time. The present invention provides a manufacturing method that does not require joining by soldering or the like and can realize a highly reliable optical connector with excellent characteristics at a low cost, and its effects are extremely large.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a mating portion of an optical connector for explaining one embodiment of the present invention, Fig. 2 is a cross-sectional view showing another embodiment, and Fig. 3 is a connection of an optical connector according to the present invention. FIG. 4A-0, which is a cross-sectional view showing an example, is a diagram showing the shape of the fiber end face and the tendency of the relationship between the gap and the loss. 10... Ferrule 11... Opening 12...
・Sleeve guide 13...Fiber guide 21...Sleeve 22...Fiber 23・
... Covering 29 ... Spherical part 30 ... Heat shield plate 35 ... Micro torch.

Claims (2)

[Claims] (1) An opening having a predetermined depth, a sleeve guide having a diameter smaller than the diameter of the opening and bored deep into the opening, and a sleeve guide bored deep into the sleeve guide. a ferrule having a fiber guide having a diameter smaller than the diameter of the sleeve guide; a ferrule that fits into the sleeve guide, a tip of the ferrule protrudes into the opening, and a fiber is inserted into the center of the ferrule through the fiber guide; an optical connector having a sleeve made of a material having substantially the same melting point as the fiber, wherein the protruding portion of the sleeve into which the fiber protruding into the opening is inserted is heated; A method for manufacturing an optical connector having a spherical part, characterized in that by melting, a convex spherical part is formed by the surface tension of the heated and melted material. (2) A light beam having a spherical portion according to claim 1, in which a heat shield plate with a hole in the opening portion is applied to the ferrule, and the protruding portion is heated and melted with a micro torch. How to manufacture connectors.