JPH087289B2 - Mechanical sleeve for optical fiber - Google Patents

Description

The present invention relates to a mechanical sleeve used for connecting optical fibers in optical communication.

(Prior Art) FIG. 5 is an explanatory view of a conventional mechanical sleeve.
As shown in the figure, the optical fiber core wire (B) is placed on the V-groove substrate (11) on which the V-groove (13) is formed, the optical fiber (A) is abutted in the V-groove (13), and then the adhesive is applied. The flat plate (12) was placed from above and the above adhesive was cured and assembled and used.

(Problems to be Solved) The above-mentioned conventional mechanical sleeve has the following problems.

An optical fiber is placed in the V groove, butted, and then an adhesive is injected, and then a flat plate is superposed on it, which requires a complicated process, and it takes time to assemble,
Requires special positioning jigs and equipment.

It is necessary to inject the adhesive on site, and if it is excessively injected, it causes axial misalignment of the optical fiber, and if it is too small, internal bubbles are generated, which makes the work extremely difficult.

Since the work starts by placing the optical fiber in the V groove instead of inserting it into the hole, stable assembly work such as the optical fiber sticking out of the V groove during the work is very important. hard.

(Means for Solving the Problems) The present invention provides a mechanical sleeve that solves the above-mentioned problems, and is characterized by a V-groove substrate provided with an adhesive layer on the V-groove surface, and the V-groove substrate. A transparent flat plate having a length shorter than that of the grooved substrate, and by stacking the flat plate on the V grooved substrate with the adhesive layer interposed therebetween,
A substantially V-shaped groove slightly larger than the optical fiber is formed, and after the optical fiber is inserted into the substantially V-shaped groove, the adhesive layer is deformed by pressing the whole, and the flat plate allows the optical fiber of at least one core to be formed. The V-groove and the flat plate are configured to be pressure-fixed, and the V-groove is provided with exposed portions on both sides of the flat plate.

FIG. 1 is a perspective view of a specific example of a mechanical sleeve for an optical fiber of the present invention, and FIG. 2 is a sectional view taken along line XX of FIG. 1 in a state where an optical fiber is inserted into the sleeve of FIG.

In the drawings, (1) is a V-groove substrate having a V-groove (3) formed on its upper surface, (2) is a flat plate made of a transparent material laminated on it with an adhesive layer (4), and (5) is It is a substantially V-shaped groove formed by stacking the V-shaped grooved substrate (1) and the flat plate (2).

As shown in FIG. 2 (a), when the optical fiber (A) is inserted into the substantially V groove (5), a clearance (g) of about 4 to 5 mm is provided between the flat plates (2). Have Such an approximately V groove (5) is provided with an adhesive layer (4) such as a hot melt adhesive on the upper surface of a flat substrate (1 ') as shown in FIG. It is formed by processing.

The sleeve formed by superimposing the flat plate (2) on the V-groove substrate (1) has a shorter length of the flat plate (2) than the V-groove substrate (1). It has an exposed portion (6) where a part of the V groove (3) is exposed on both sides, which facilitates insertion of the optical fiber (A) into the substantially V groove (5).

In FIG. 2 (a), a hot-melt adhesive is used as the adhesive layer (4), and it is 4 to the outer diameter of the optical fiber (A).
When a V groove (5) having a clearance (g) of about 5 mm is formed and the optical fiber (A) is inserted therein and the whole is heated, the hot melt adhesive layer (4) is melted, The pressurized flat plate (2) is compressed until the optical fiber (A) is fixed under pressure as shown in FIG. 2B, and at least the optical fiber having the largest outer diameter is clamped, resulting in hot melt. The adhesive (4 ') is cooled and solidified to fix the optical fiber (A) and the flat plate (2). In particular, for high-precision connection of single-mode fibers and the like, it is essential to reduce the insertion clearance, and this structure can be said to be an extremely effective means.

Further, as shown in FIG. 6, an ultraviolet ray or thermosetting adhesive / refractive index matching agent (8) is previously injected into the V groove of the V groove substrate (1), and after the optical fiber is inserted, the ultraviolet ray is irradiated. Alternatively, the optical fiber (A) can be fixed by heating and the matching effect can be realized together. In this case, by making the flat plate (2) transparent, it is possible to improve the transmission of ultraviolet rays and to easily observe the butted state of the optical fibers (A), which is effective for ensuring reliability. Further, it is desirable that a mask sheet (9) is provided on the upper surface in order to prevent natural light during storage and prevent hardening of the resin.

Further in FIG. 2, a hot melt adhesive layer (4)
By utilizing the refractive index matching effect as above, the three effects of the optical fiber insertion clearance, the optical fiber fixing, and the matching agent effect are exhibited at the same time, and it is extremely effective in improving the assemblability, reliability and characteristics.

For fixing the optical fiber core portion, a tab is provided on the flat plate, and the optical fiber core portion is fixed by engaging with the V-groove substrate or the base that houses the V-groove substrate, or an elastic clip (see FIG. 3). The flat plate and the V-groove substrate or the base may be fixed by 7). further,
The mechanical sleeve of the present invention is a basic element, and it may be used by housing it in a housing.

In the description of the present invention, the one using the hot-melt adhesive layer as the adhesive layer has been described above, but a rubber-based adhesive or an epoxy-based adhesive may be used, but the viscosity becomes low during pressure compression and the V-groove Those having the characteristic of flowing into

(Example) As the V-groove substrate, precision processable silicon was used, and as the flat plate, glass was used.
They were joined with a hot melt agent having a refractive index matching effect of μm and fixed with an elastic clip as shown in FIG. The substantially V groove formed at this time had an inscribed circle of 135 μmφ so that an optical fiber of 128 μmφ could be easily inserted. Ten V-grooves were formed and tested using a single mode fiber.

Insert 10 optical fibers with an outer diameter of 125 μmφ, heat to a temperature of about 150 ° C for a certain period of time to soften and melt the hot-melting agent, pressurize the clip member, and let it flow into the gap between the optical fiber and the V groove, and then fix by cooling. Let At this time, the inscribed circle of the V groove was designed to be 100 μm at the maximum and used 125 μm ± 0.
An optical fiber with an outer diameter of 5 μm was fixed by pressure with a flat plate. The optical fiber is cut by a fiber cutter, inserted from both sides, and fixed in a state of being abutted in the V groove. At this time, since the flat plate was transparent, the butted state could be easily observed with a microscope or TV monitor, and the length could be adjusted.

The characteristics of the obtained connection part are N = 20 samples, total 200
The average is 0.16 dB in mind, and it is extremely low loss considering the simple connection. Also, regarding the temperature characteristics, -20 ℃ to + 60 ℃
It was confirmed that the fluctuation was within ± 0.05 dB within the range of, and the stability of the optical fiber was also high. Furthermore, it was found that the tensile strengths were all 3 kg or more, which was practically sufficient.

In the present invention, in addition to the hot melt adhesive, a relatively high viscosity resin such as an ultraviolet curable resin or a thermosetting resin that does not flow out even if the V groove is vertical is injected.
Needless to say, this may be used to generate the fixing or matching effect of the optical fiber. In this case, it may be injected into the assembled V groove hole later, or naturally by inserting the optical fiber. The matching effect can be easily set because the internal resins are butted.

Further, a hot melt sheet may be used for forming the hot melt adhesive layer, and in this case, it is preferable that after the hot melt sheet is attached, V groove processing is performed to form substantially V grooves. (Refer to FIG. 4) (Effect of the Invention) According to the mechanical sleeve for an optical fiber of the present invention described above, the following effects are listed.

Since the V-groove substrate and the flat plate are joined to each other to form the V-groove and the exposed portions of the V-groove are provided on both sides, insertion of the optical fiber is extremely easy and stable.

By forming the clearance with the hot-melt adhesive layer, the insertion of the optical fiber can be facilitated, and the optical fiber can be thermally deformed to clamp the outer diameter of the optical fiber and the optical fiber can be positioned with high accuracy.

By using the hot melt adhesive having the refractive index matching effect, it is possible to realize the clearance formation, the fixing of the optical fiber and the matching effect at the same time.

By injecting the adhesive into the V-groove in advance, it is possible to eliminate the trouble of injecting the adhesive on site, easily fix the optical fiber, and achieve the matching effect.

[Brief description of drawings]

FIG. 1 is a perspective view of a specific example of a mechanical sleeve for an optical fiber of the present invention, and FIGS. 2A and 2B are XX of FIG. 1 in a state where an optical fiber is inserted into the sleeve of FIG. FIG. FIG. 3 is a transverse sectional view of the sleeve of FIG. 1 fixed with an elastic clip. FIGS. 4A and 4B are explanatory views of an example of the procedure for forming the substantially V groove. FIG. 5 is an explanatory view of a procedure for assembling a conventional mechanical sleeve. FIG. 6 is a cross-sectional view of another example of the mechanical sleeve of the present invention. A ... Optical fiber, B ... Optical fiber core wire, 1 ... V groove substrate, 2 ... Flat plate, 3 ... V groove, 4 ... Adhesive layer, 5 ... V groove, 6 ... V-groove exposed part, 7 ... Elastic clip, 8 ... UV or thermosetting resin.

Claims (5)

[Claims] 1. A mechanical sleeve in which an optical fiber is inserted into a positioning V-groove to realize mutual coupling, and a V-groove substrate having an adhesive layer on the V-groove surface and a length longer than the V-groove substrate. The flat plate is made of a short transparent flat plate, and the flat plate is superposed on the V-groove substrate via the adhesive layer to form a substantially V-groove slightly larger than the outer diameter of the optical fiber. After the fiber is inserted, the adhesive layer is deformed by pressurizing the whole, and the flat plate pressurizes and fixes at least one optical fiber or more in the V groove and the flat plate, and A mechanical sleeve for an optical fiber, characterized in that the flat plate is provided with exposed portions in which a part of the V groove is exposed. 2. The adhesive layer is a hot melt adhesive layer,
The flat plate elastically pressed by the thermal deformation of the layer causes at least one optical fiber to be fixed under pressure by the V groove and the flat plate. Mechanical sleeve for optical fiber. 3. An optical fiber according to claim 1, wherein a resin which also serves as an ultraviolet ray or thermosetting adhesive and a refractive index matching agent is previously injected into the substantially V groove. Mechanical sleeve. 4. The hot melt adhesive layer flows into the V groove due to thermal deformation to be cooled and solidified to fix the optical fiber and to act as a refractive index matching agent. Optical fiber mechanical sleeve. 5. A mechanical sleeve for an optical fiber according to claim 1, wherein the V-groove substrate and the flat plate superposed thereon are clamped by an elastic clip member.