JPH0325403A - Optical attenuator - Google Patents

Abstract

PURPOSE:To contrive the simplification of construction, the shortening of assembly time and the decrease of the fluctuation in attenuation rate by assembly and adjustment by inserting a 2nd optical fiber into the small-diameter hole of a capillary from the side opposite to the side where a 1st optical fiber is inserted and matching and fixing the optical fibers via a refractive index matching material to an optical attenuating film. CONSTITUTION:This optical attenuator is constituted by having a ferrule 14 made of the construction in which the 1st optical fiber 10 formed with the optical attenuating film 10a on the diagonally cut end face and the 2nd optical fiber 11 having the perpendicularly cut end face are butted against each other via an adhesive agent 13 having a refractive index matching effect within the small-diameter hole 12a of the capillary 12. This small-diameter hole 12a of the capillary 12 is formed to the size slightly larger than the outside diameter of the 1st, 2nd optical fibers 10, 11. The smaller number of the parts is necessitated in this way and the construction is simplified. The assembly is executable in a short period of time and the fluctuation in the attenuation rate by the assembly and adjustment is decreased.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical attenuator used in optical communications.

[Conventional technology]

Optical attenuators are used for arranging transmission line losses and adjusting the level of optical equipment, and a typical optical attenuator that has been used in the past is shown in FIG.

FIG. 5 shows a plug-and-jack type fixed attenuator, which is used by fitting into an optical connector. As shown in FIG. 5, the conventional optical attenuator consists of a divided l-th
A light attenuation g3 is formed on the ferrule 1 or the second ferrule 2, and these two ferrules 1 and 2 are aligned with a sleeve 4.
, 5, and after rotating and adjusting the ferrules 1 and 2 to the position where the connection loss between the ferrules 1 and 2 is minimized,
Ferrules 1 and 2 are fixed. Note that the first and second ferrules 1 and 2 have a structure in which optical fibers 8 and 9 are built in via capillaries 6 and 7, respectively.

[Problem to be solved by the invention]

However, in the conventional optical attenuator described above, since the ferrule is divided into two pieces (first ferrule l1 and second ferrule 2), there are also two alignment sleeves (alignment sleeves 4, 5). ), and as a result, the number of parts increased, the structure was complicated, and it took a long time to assemble, making it difficult to reduce the cost of the optical attenuator. In addition, the first and second ferrules 1 are arranged in the alignment sleeves 4 and 5.
, 2, it is necessary to align the two oblique end faces to the optimum position, which also has the disadvantage of causing variations in the amount of attenuation.

The object of the present invention has been made in view of the above-mentioned drawbacks.
It is an object of the present invention to provide an optical attenuator that has a simple structure, can shorten assembly time, and can reduce variations in attenuation due to assembly adjustments.

[Means to solve the problem]

In order to achieve the above-mentioned object, an optical attenuator according to the present invention is provided with a wire pillar having a small diameter hole slightly larger than the outer diameter of an optical fiber, and a first pillar having a light attenuating film formed on the end surface. An optical fiber is inserted and fixed from the optical attenuation film side to a midway position in the small diameter hole of the capillary, and a second optical fiber is inserted from the opposite direction to the first optical fiber insertion side of the small diameter capillary hole. , which has a ferrule structure that is butted against and fixed to the light attenuation film via a refractive index matching agent.

[Effect]

In this way, in the present invention, since the ferrule is not divided, only one alignment sleeve is required.

Therefore, the number of parts is small, the structure is simple, and assembly can be performed in a short time. Furthermore, since the first and second optical fibers are butted against each other inside the highly precisely machined capillary, variations in attenuation due to assembly adjustments can be reduced.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of an optical attenuator according to the present invention. The optical attenuator of this embodiment includes a first optical fiber 10 having an obliquely cut end face formed with a light attenuating film 10a, and a second optical fiber 10 having a perpendicularly cut end face.
1 and ferrule 14 are butted together in the small diameter hole 12a of the capillary l2 with an adhesive 13 having a refractive index matching function interposed therebetween. The small diameter hole 12a of this capillary 12 is shaped to be slightly larger than the outer diameter of the first and second optical fibers 10 and l1.

Now, to explain in more detail the method for manufacturing the ferrule l4, first, as shown in FIG. 2, an adhesive 13 having a refractive index matching effect is applied to the first optical fiber 10, and as shown in FIG. , small diameter hole 12a of capillary 12
After inserting it to approximately the middle position, fix it. Next, after applying the same adhesive 13 as described above to the second optical fiber 11, as shown in FIG. After heating and curing, fix.

In this case, the adhesive 13 should not adhere to the abutting surfaces of the first and second optical fibers 10 and 11, and an adhesive that does not have a refractive index matching effect should be applied to the first and second optical fibers 10 and 11. It may be used only for fixing, and a jelly-like refractive index matching agent may be injected into the abutting surfaces of the 11th and 2nd optical fibers IO and 11(7).

Finally, the protruding portions of the first and second optical fibers 10 and 1l protruding from the ferrule 14 are removed, and both end surfaces 14a and 14b of the ferrule are polished (see FIG. 4).

An alignment sleeve 15 and a spring l6 are attached to the outer periphery of the ferrule 14 manufactured in this manner, and the ferrule 14 is tied to the housing 17. In the optical fixed attenuator of this embodiment, the side having the coupling nut 18 functions as a plug of an optical connector, and the opposite side functions as an adapter. In this way, in this optical attenuator, unlike the conventional optical attenuator shown in FIG. 5, the ferrule 14 is not divided, so only one alignment sleeve 15 is required, and the structure is simple and assembly is short. You can do it with Also, inside the highly precisely machined capillary 12, the first and second optical fibers 1
Because of the structure in which 0 and 11 butt each other, variations in the damping receiver due to assembly adjustment can be made smaller than in the past.

In addition, in the embodiment described above, the first potential fiber 1
The end face of 0 is cut diagonally, and the light attenuation film 1 is placed on this slanted end face.
Although the shape is not limited to this, for example, the end face of the second optical fiber 11 may be cut obliquely, and a light attenuating film may be formed on this inclined end face. Good too.

〔Effect of the invention〕

As explained above, according to the optical attenuator according to the present invention,
Because the ferrule is not divided, it requires fewer parts than conventional structures, and therefore has a simpler structure.Moreover, it can be assembled in a shorter time than conventional structures, making it possible to reduce costs. be effective.

Also, inside the highly precisely machined capillary, the first and second
Because of the structure in which the optical fibers are butted together, it is also possible to reduce variations in attenuation due to assembly adjustment compared to the conventional method.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of the optical attenuator according to the present invention, FIGS. 2 to 4 are explanatory diagrams for explaining the manufacturing method of the ferrule shown in FIG. 1, and FIG. FIG. 2 is a longitudinal cross-sectional view showing an example of a conventional optical attenuator. 10...Lth optical fiber, 10a...Light attenuation film, 1l...Second optical fiber, 12...Capillary, 12a... ...Small diameter hole, 13...Adhesive, 14...Ferrule, 15...Alignment sleeve.

Claims (1)

[Claims] A first optical fiber comprising a capillary having a small diameter hole slightly larger than the outer diameter of the optical fiber and having a light attenuating film formed on the end face is formed with a light attenuating film up to a midway position of the small diameter hole of the capillary. A ferrule is inserted and fixed from the side, and a second optical fiber is inserted from the opposite direction to the first optical fiber insertion side of the capillary small diameter hole, and abutted and fixed to the light attenuation film via a refractive index matching agent. An optical attenuator characterized by having a structure.