JPH0212113A - Manufacture of optical connector - Google Patents

Abstract

PURPOSE:To easily hold a ferrule end surface on a horizontal surface by making an optical fiber end surface which is processed or cut into an orthogonal plane abut on an abutting plate and aligning a ferrule end surface and the optical fiber end surface with each other, and adhering and fixing an optical fiber in the insertion hole of a ferrule. CONSTITUTION:The end surface of the optical fiber 11 of a coated optical fiber 10 is ground and the ground surface is stepped and exposed. An adhesive 2 is injected into the optical fiber insertion hole 1a of the ferrule 1 and the coated optical fiber 10 which is given the step is inserted and pushed in until the terminal of the optical fiber 11 projects slightly from the ferrule end surface 1b to cause the adhesive 2 overflow. Then the optical fiber 11 is returned slightly from the ferrule end surface and after an adhesive sticking on the ferrule end surface 1b is wiped away, the ferrule end surface 1b is made to abut on the abutting plate 3 in contact; and the end surface of the optical fiber 11 is allowed to abut on the abutting plate 3 and the fiber 10 is fixed in this state. Consequently, the connector end surface is held on the horizontal surface without grinding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an improvement in a method of manufacturing an optical connector for detachably connecting an optical cable or the like.

[Prior Art] Optical cables or optical cords are often detachably connected using optical connectors when connecting to devices or connecting cords to each other.

Optical fibers connected by such optical connectors are
It has an extremely small diameter, and even a slight deviation in alignment of the end faces at the connection in the radial or axial direction will lead to an increase in transmission loss at the connection.

For this reason, optical connectors are required to have high processing accuracy on the order of submicrons. In order to satisfy this requirement, various proposals have been made for aligning and non-aligning types, but the alignment method using precision ferrules of the non-aligning type eliminates the need for alignment during connection, as long as processing accuracy can be ensured. There is a big advantage that there is no

The conventional method for manufacturing the precision ferrule described above is, for example, as shown in FIG. A precision insertion hole 1a is formed in the ferrule 1 to allow the optical fiber 11 exposed by stripping the coating of the optical fiber core 10 to pass therethrough, and an adhesive 2 is injected into the ferrule 1 to remove the coating as shown in the figure. The optical fiber 11 thus prepared is inserted and fixed by the injected adhesive 2.

At this time, the optical fiber 11 is initially made to protrude from the end face 1b of the ferrule 1 as shown in the figure, and the ferrule end face 1b is finished polished, and the optical fiber 11
The end face of the ferrule and the end face 1b of the ferrule are precisely positioned on the same plane.

In the above, since the optical fiber 11 protruding from the ferrule end face 1b is made of glass, if it breaks, there is a risk that the crack will propagate to the optical fiber inside the ferrule 1. , separately apply adhesive 2a as shown in the figure, then bend the protruding optical fiber 11 at an appropriate position away from the ferrule end face 1b, remove the excess length, and attach the ferrule end face together with the adhesive 2a. It is polished.

[Issue to be Solved by the Invention 1M1 In the above polishing, there is not much of a problem when the optical fiber is a single core, but in the case of a multi-core ferrule that holds two or more optical fibers, the above-mentioned reinforcing adhesive Since the amount of 2a differs slightly in each optical fiber,
The ferrule end face 1b after polishing does not become a strictly horizontal surface,
In many cases, the surface is polished into a curved shape as shown in FIG. Then, as shown in FIG. 5, a gap G is created between the end faces 1b and lb of the ferrule 1.1 that are butted together during the connection, which impedes the alignment of the optical fiber 11 and results in a large connection loss. . Especially recently, 20-6
Even zero-core connectors are being considered, and the finishing of the ferrule end face has become a major issue.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing an optical connector, which eliminates the drawbacks of the prior art described above and allows the ferrule end face to be easily maintained in a horizontal plane.

[Means for Solving the Problems] The present invention uses a contact plate that can closely contact the ferrule end face without polishing the ferrule end face as in the conventional example. Then, the ferrule end face and the optical fiber end face are brought into alignment by abutting the end face of the optical fiber whose end face has been previously processed or cut into a perpendicular plane against a contact plate, and in this state, the optical fiber is adhesively fixed in the insertion hole of the ferrule. It is.

"Function" It is easy to process the ferrule end face into a flat surface, and if the optical fiber end face can be matched with the end face,
There is no need to perform end face polishing again. Therefore, the connector end face can be maintained in a horizontal plane without polishing, which eliminates the possibility of a gap occurring between the end faces of the ferrules when they are butted together as connectors. be.

[Example] The present invention will be described below with reference to the drawings.

2 and 3 are explanatory diagrams showing how a connector is formed by the method according to the present invention.

Optical fiber 1 of optical fiber core wire 10 shown in FIG. 1(a)
The end face of 1 is polished smooth using a special tool, and the steps are peeled off and exposed as shown in FIG.

Recently, ultraviolet curing resin has been used to coat the core wire 10, but this resin is swollen with a methylene chloride solution and removed without damaging the fiber.

On the other hand, adhesive 2 is injected into the optical fiber insertion hole 1a of the ferrule 1 as shown in FIG. Push in until the end of the ferrule slightly protrudes from the end face 1b of the ferrule, causing the adhesive 2 to overflow. Next, the optical fiber 11 is moved back slightly from the ferrule end face, and the adhesive adhering to the ferrule end face 1b is wiped off with a solvent and gauze. After that, a contact plate 3 made of, for example, a glass plate is brought into close contact with the ferrule end face 1b, and the end face of the optical fiber 11 is abutted against the contact plate 3, and in this state, the core wire 10 is attached to the temporary fixing protrusion IC of the ferrule. Temporarily fix it with instant adhesive 4. After the temporary fixation, the contact plate 3 is removed, and the adhesive 2 inside the ferrule 1 is heated and hardened.

As the adhesive 2, it is preferable to use a highly reliable adhesive such as an epoxy adhesive, and to cure it for about one hour.

With the above steps, the attachment of the optical fiber 11 to the ferrule 1 is completed.

According to the present invention, since the ferrule end face 1b is not polished, the end face is not curved due to polishing as in the conventional example described above, and therefore, the possibility of creating a gap and causing connection loss is eliminated.

For the purpose of experiment, a connector in which 20 optical fibers each having a core diameter of 50 μm and an outer diameter of 125 μm were arranged in series at a pitch of 0.3 mm was manufactured by the manufacturing method according to the present invention. As a result of measuring the splice loss at this time without using a refractive index matching agent, an extremely good result of 0.35 to 1.0 dB could be obtained.

[Effects of the Invention] As described above, according to the present invention, the following excellent effects can be obtained.

(1) Since the end face of the ferrule is not polished after the optical fiber is inserted, the perpendicularity and horizontality of the end face of the ferrule is ensured, and connection loss during connector connection can be minimized.

(2) Since the perpendicularity and smoothness of the fiber end faces can be carefully selected individually, variations in connection characteristics can be reduced.

(3) Only the end face of the fiber needs to be polished in advance, making it possible to downsize the polishing machine and making work at the construction site easier.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the state of step stripping of an optical fiber, Figs. 2 and 3 are explanatory cross-sectional views showing the situation in which the ferrule according to the present invention is attached, and Fig. 4 is an explanatory diagram showing the situation in which the conventional ferrule is attached. The sectional view and FIG. 5 are explanatory diagrams showing a butting situation when the ferrule end face is curved. 1: Ferrule, 1a: Optical fiber insertion hole, 1b: Ferrule end face, 1c: Protrusion for temporary fixing, 2: Adhesive, 3: Contact plate, 4: Adhesive for temporary fixing, 10: Optical fiber core wire, 11 : Optical fiber. Figure 4 Optical fiber

Claims (1)

[Claims] (1) In the manufacture of connectors in which an optical fiber is inserted into the optical fiber insertion hole of a precision ferrule and fixed with adhesive,
A contact plate is placed in close contact with the end face of the ferrule, an optical fiber whose end face has been treated in advance is inserted into the optical fiber insertion hole, and the end face is brought into contact with the contact plate, and the end face of the ferrule and the end face of the optical fiber are brought into contact with the contact plate. A method of manufacturing an optical connector that is aligned and fixed with adhesive.