JPH04221911A - Production of low-reflection optical connector - Google Patents

Abstract

PURPOSE:To prevent the attenuation of light by applying an adhesive having about the same refractive index as the refractive index of core parts on the end faces of optical fibers and bringing a connecting end face into tight contact with a smooth plate, then curing the adhesive. CONSTITUTION:The UV curing type adhesive 13, the cured matter of which has about the same refractive index of the refractive index of the core parts of the optical fibers, is applied on the connecting end face 10. The smooth plate 14 is then brought into tight contact with the connecting end face 10 coated with the adhesive 13. The smooth plate 14 is shifted to allow the air to escape so as not to generate gaps between the connecting end face 10 and the adhesive 13 and between the adhesive 13 and the flat plate 14. The thickness of the adhesive 13 is uniformized by applying a specified pressure between the connecting end face 10 and the smooth plate 14. The adhesive 13 is thereafter irradiated with UV light through the smooth plate 14, by which the adhesive 13 is cured. The smooth plate 14 is thereafter removed from a connector body 1. Then, the adhesive layer having a smooth surface is formed on the connecting end face 10 of the connector body 1.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a low-reflection optical connector used for connecting optical fibers.

0002

2. Description of the Related Art Conventionally, MT connectors have been manufactured as follows. First, a through hole for fiber insertion is formed in a ferrule made of plastic, that is, a connector body. Next, the optical fiber is inserted into the through hole so that the end surface of the optical fiber is flush with the end surface of the connector body. Next, in this state, the end face of the connector main body is polished together with the end face of the optical fiber to smooth the end face of the connector main body and the end face of the optical fiber. Thereby, an MT connector is obtained.

[0003] When connecting MT connectors, both ends of a fitting pin are inserted into respective fitting holes formed in advance on the end face of the MT connector, and abutted against each other so that the optical axes of each optical fiber are aligned. The end faces of each MT connector are not polished completely smooth, so when the two are butted together, a gap is generated at the joint surface. For this reason, MT
The optical signal transmitted at the connector joint may be lost or the return loss of light may be deviated.

In order to prevent this gap from occurring, a matching agent such as liquid matching oil or gel matching grease is applied to the joint surface, that is, the end face of the MT connector, or the MT connector is sealed in advance.
A film with a refractive index close to that of the optical fiber core is attached to the end face of the optical fiber.

[0005]

However, when applying a matching agent to the end face of an MT connector, it is necessary to clean the end face of the MT connector in advance. Furthermore, if foreign matter enters the matching agent during application of the matching agent, a portion of the optical signal will be reflected by the foreign object, which will have a negative effect on the transmission of the optical signal.

On the other hand, when attaching a film to the end face of an MT connector, the M
Since the T connectors are separated from each other, the distance between the cores of each optical fiber increases. Therefore, the loss of the optical signal to be transmitted at the MT connector joint portion increases. Moreover, in this case, since the film is applied to a relatively small area, a sophisticated application technique is required.

The present invention has been made in view of the above points, and provides a low reflection optical connector that does not form a gap on the optical axis of an optical fiber and can sufficiently prevent light attenuation at the end face of the fiber. The purpose is to provide a method that can efficiently manufacture.

[0008]

[Means for Solving the Problems] The present invention provides a method in which a cured product is applied to at least the connecting end surface of a connector body into which an optical fiber is inserted so that the fiber end surface is exposed, to the same extent as the core portion of the optical fiber. A method for manufacturing a low reflection optical connector is provided, which comprises applying an adhesive having a refractive index, bringing the connection end surface into close contact with a smooth plate, curing the adhesive, and then removing the smooth plate.

[0009]

[Operation] According to the method of manufacturing a low-reflection optical connector of the present invention, an adhesive whose cured material has a refractive index similar to that of the core of the optical fiber is applied to the connection end face, and the surface is smoothed using a smooth plate. Forms a smooth adhesive layer. Therefore, optical fibers can be connected to each other without forming a space on the optical axis of the optical fibers. Therefore, the optical signal is transmitted without loss.

0010

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing a connector body used in the present invention. In the figure, 1 indicates the connector body. A plurality of fiber insertion holes are formed in the connection end surface 10 of the connector body 1, and the optical fibers 1 are inserted into the holes.
1 is inserted so that its fiber end face is exposed. Moreover, two positioning pin holes 12 are formed in advance in the connection end surface 10. The connection end face 10 is polished together with the fiber end face.

First, the connection end surface 10 of the connector body 1 is cleaned to remove foreign matter. Next, as shown in Figure 2,
A UV curable adhesive 13 whose cured material has a refractive index comparable to that of the core portion of the optical fiber is applied onto the connection end surface 10 . Next, as shown in FIG. 3, the smooth plate 14 is brought into close contact with the connection end surface 10 coated with the adhesive 13, and the connection end surface and the adhesive are bonded together.
The smooth plate 14 is shifted to allow air to escape so that no gap is generated between the adhesive and the smooth plate. Note that it is necessary to select a material for the smooth plate 14 that can transmit UV light. Further, the material of the smooth plate 14 needs to be selected from a material that has a low adhesive strength to the adhesive so that the smooth plate can be easily removed after the adhesive has hardened. Since the surface roughness of the smooth plate affects the roughness of the surface of the adhesive layer obtained, it is preferable that the surface roughness be as small as possible. Next, a constant pressure is applied between the connecting end surface 10 and the smooth plate 14 to make the thickness of the adhesive 13 uniform. Then, as shown in FIG.
UV light is applied to 3 through the smooth plate 14 and adhesive 1
Cure 3. After this, from the connector body 1 to the smooth plate 1
Remove 4. As a result, an adhesive layer with a smooth surface is formed on the connection end surface 10 of the connector body 1. Finally, after cutting the adhesive layer protruding from the connection end surface 10,
The adhesive layer is irradiated with UV light to completely cure the adhesive. In this way, a low reflection optical connector can be manufactured.

[0012] Insert a pin into each of the positioning pin holes 12 of the two optical connectors thus obtained,
When the two were joined by butting their connection end surfaces against each other so that their optical axes were aligned, it was confirmed that the optical fibers could be connected without creating a gap on the optical axis of the optical fiber.

In this example, a UV-curable adhesive was used, but the cured product had a refractive index similar to that of the core of the optical fiber (approximately 1
．． 47) can be used. In addition, in this embodiment, an adhesive layer is provided on the entire surface of the connection end surface of the connector body, but as shown in FIG. Alternatively, the adhesive layer may be provided only in the region 26 of the connection end surface 10 that includes the fiber end surface by using a smooth plate 24 whose other portion 22 is UV-opaque. In this case, since the adhesive layer is formed without protruding from the connection end surface 10, the step of cutting the excess adhesive layer can be omitted.

[0014]

[Effects of the Invention] As explained above, the method for manufacturing a low reflection optical connector of the present invention does not form a gap on the optical axis of an optical fiber, and can sufficiently prevent light attenuation at the fiber end face. A low reflection optical connector can be manufactured efficiently. Furthermore, since the adhesive layer of the low-reflection optical connector has elasticity, it is possible to apply pressure when connecting the connector. As a result, the thickness of the adhesive layer becomes relatively thin, and as a result, the loss of light that occurs during connection can be further suppressed. Further, according to the present invention, it is possible to omit the step of applying a matching agent to the connection end surface of an optical connector at an optical fiber construction site, and the optical connector can be easily attached and detached, so that the work time can be shortened. .

[0015]

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a connector main body used in the present invention.

FIG. 2 is an explanatory diagram showing a case where an adhesive is applied to the connector body of FIG. 1;

FIG. 3 is an explanatory diagram showing a case where a smooth plate is brought into close contact with the connector body of FIG. 2;

FIG. 4 is an explanatory diagram showing a case where UV light is irradiated in the state shown in FIG. 3;

FIG. 5 is an explanatory diagram showing another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Connector main body, 10... Connection end surface, 11... Optical fiber, 12... Pin hole for positioning, 13... Adhesive, 14... Smooth plate.

Claims (1)

[Claims] 1. Applying an adhesive whose cured material has a refractive index similar to that of the core of the optical fiber on at least the fiber end surface of the connection end surface of a connector body into which the optical fiber is inserted so that the fiber end surface is exposed. A method of manufacturing a low-reflection optical connector, comprising: bringing the connecting end surface into close contact with a smooth plate, curing the adhesive, and then removing the smooth plate.