JPH05210026A - Coupling structure of optical waveguide and optical fiber - Google Patents

Abstract

(57) [Abstract] [Purpose] To securely connect an optical connector block holding an optical fiber and an optical waveguide block having an optical waveguide without misaligning the optical axis. [Structure] A flange portion 14a of an optical connector block 12 holding an optical fiber 11 is fixed to an optical waveguide block 13 having an optical waveguide 18a by YAG welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coupling structure for an optical waveguide and an optical fiber.

[0002]

2. Description of the Related Art Conventionally, in order to couple an optical waveguide and an optical fiber, each end face of an optical element having an optical waveguide formed on a substrate and a connector connected to the optical fiber are butted, and the butted portion is bonded by UV resin or YAG welding. It is stuck due to. This conventional method will be described with reference to FIGS. 6 and 7. The optical connector 2 connected to the end of the optical fiber 1 is brought into contact with both end surfaces of the optical element 3 having an optical waveguide, and the contact is made. The part 4 is fixed by UV adhesion or YAG welding. In UV bonding, a UV curable resin material of a fluid is applied to the edge portions of the optical element 3 and the optical connector 2 to bond them, but the UV resin material shrinks when it cures, so that The element 3 and the optical connector 2 are displaced and an optical axis shift is generated between the optical waveguide and the optical fiber. However, since the optical fiber connection requires alignment with an accuracy of 0.1 μm, the above-mentioned problem of optical axis deviation cannot be ignored.

Also, in the case of welding using a YAG laser, the contact surfaces 5 of the optical element 3 and the optical connector 2 are welded at, for example, four side edges, as shown in FIG. In doing so, thermal stress is generated and the optical element 3 and the optical connector 2 move in the X direction in FIG. 7, and the movement is likely to be non-uniform at the welded portions on each side. The fixation becomes uncertain and the optical axis is likely to shift.

[0004]

As described above, in the conventional coupling structure in which the end surface of the optical element and the end surface of the optical connector are butted and the contact surface is fixed by UV adhesion or YAG welding, the optical element and the optical connector are connected. Is uncertain,
There is a problem that the optical axis is displaced at the connection between the optical waveguide and the optical fiber.

An object of the present invention is to provide a coupling structure between an optical waveguide and an optical fiber which solves the above problems.

[0006]

According to the present invention, an optical waveguide and an optical fiber are fixed to a metallic optical waveguide block and an optical connector block, respectively, and a flange portion is provided at least at a connecting end portion of the one block. The flange portion and the other block are butted, and the butted portion is fixed.

Further, the abutting portion between the above-mentioned flange portion and the other block may be fixed by YAG laser welding.

[0008]

When the abutting surfaces of the respective metal blocks holding the optical waveguide and the optical fiber are fixed by YAG welding or the like from the end face direction of the flange portion, distortion caused by thermal stress or the like in the fixed portion causes the flange of one of the metal blocks. It is absorbed as a deflection of the section and does not exert an influence such as causing an optical axis shift at the connecting section between the optical waveguide and the optical fiber. Moreover, the above-mentioned abutting surface can be welded through the wall thickness of the flange portion of the metal block. In this case as well, thermal expansion occurs at the welded portion, but the presence of the flange portion does not cause optical axis deviation.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an optical connector block 1 according to the present invention.
2 is an explanatory plan view in which the optical waveguide block 13 and the optical waveguide block 13 are coupled and fixed by welding, FIG. 2 is a perspective view of the optical connector 12, and FIG. 4 is an exploded perspective view of the optical element 13.

First, referring to FIGS. 1 to 3, an optical connector block 12 has a flange portion 14a at an end thereof and a block main body 14 having a concave groove 14b inside and an optical fiber 11 fitted into the concave groove 14b. And a holding plate 16 for holding the V-groove substrate 15 in the concave groove 14b. Among these members, at least the block body 14 and the pressing plate 16 are made of a metal material such as stainless steel.
In addition, a V groove 15 a into which the optical fiber 11 fits is formed on the upper surface of the V groove substrate 15. In this case, the optical fiber 1
1 has a bare wire 11a from which the coating layer is peeled off, the tip of the V-groove 15a has a small diameter V-groove 15a accordingly.
It is assumed to be b. Then, the optical fiber 11 is fitted into the V-groove 15a of the V-groove substrate 15 and the upper part thereof is pressed by the pressing plate 16. In this state, the V-groove substrate 15 is fitted into the concave groove 14b, and the V-groove substrate 15, the block main body 14 and the pressing plate 16 are further bonded. The tip of the optical fiber 11 fitted in the V groove 15 a of the V groove substrate 15 has the V groove substrate 15 and the pressing plate 16.
It is polished so that it is aligned with the end surface of.

Next, as shown in FIG. 4, the optical waveguide block 13 has a block body 17 having a groove 17a.
And an optical waveguide substrate 18 that fits into the above-mentioned groove 17a,
It is composed of a pressing plate 19 for pressing the optical waveguide substrate 18 fitted in the groove 17a. The optical waveguide substrate 18 is
In the case of the illustrated example, it is configured to have four 2 × 2 branch circuits 18a (partly omitted in FIG. 4). Further, at least the block body 17 and the pressing plate 19 are made of a metal material such as stainless steel. Then, the above-mentioned optical waveguide substrate 18 is fitted into the concave groove 17a, adhered to the block body 17, and further, the pressing plate 19 is attached to the upper surface of the block body 17.
Glue. Then, the optical waveguide substrate 18 and the block 1
The optical waveguide block 13 is obtained by polishing so that the end faces of 7 are aligned.

To connect the optical connector block 12 and the optical waveguide block 13 configured as described above, as shown in FIG. 1, the core of the optical fiber held in each block and the core of the optical waveguide are in contact with each other. While aligning, the end face of the optical connector block 12 and the end face of the optical waveguide block 13 are brought into close contact with each other. This flange part 1 is irradiated with laser.
4a is welded to the optical waveguide block 13. In this case, A
When welding from the direction, the place where the YAG laser welds 2
A thermal stress is generated at 0, and a force acts on the optical connector block 12 and the optical waveguide block 13 such that the core portions of the optical fiber 11 and the optical waveguide 18a are displaced from each other. The core portions of the optical fiber 11 and the optical waveguide 18a are not displaced by being absorbed by the deflection of the portion 14a. When the thickness of the flange portion 14a is 1 mm or less, penetration welding can be performed from the direction B in FIG. In this case as well, thermal expansion occurs at the welded portion 20, but due to the presence of the flange portion 14a, stress does not act in a direction that accommodates the gap between the block body 14 and the pressing plate 19.

[0014]

As described above, according to the present invention,
When connecting the optical fiber and the optical waveguide, the flange of the optical connector is fixed to the optical waveguide block by YAG welding, etc., so distortion such as thermal stress generated in this fixed portion can be reliably absorbed by the bending of the flange described above. Therefore, it is possible to eliminate the factor that causes the optical axis shift between the optical fiber and the optical waveguide and reduce the connection loss.

[Brief description of drawings]

FIG. 1 is a plan view showing a state in which an optical connector block and an optical waveguide block are fixed to each other.

FIG. 2 is a perspective view of an optical connector block.

FIG. 3 is a perspective view of an optical fiber and a V-groove substrate.

FIG. 4 is a perspective view showing each member of the optical waveguide block separately.

FIG. 5 is a plan view of an optical waveguide.

FIG. 6 is a perspective view showing a conventional method for connecting an optical connector and an optical element.

FIG. 7 is an enlarged perspective view showing a connection portion formed by conventional YAG welding.

[Explanation of symbols]

11 ... Optical fiber, 12 ... Optical connector block, 13 ...
Optical waveguide block, 14 ... Block body, 14a ... Flange portion, 15 ... V groove substrate, 15a ... V groove, 16 ... Holding plate, 17 ... Block body, 18 ... Optical waveguide substrate, 18a
... optical waveguide, 19 ... pressing plate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shinji Ishikawa 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works (72) Hiroshi Yokota 1 Taya-cho, Sakae-ku, Yokohama, Kanagawa Sumitomo Denki Kogyo Co., Ltd. Yokohama Works (72) Inventor Masahide Saito 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Denki Kogyo Co., Ltd. Yokohama Works

Claims (2)

[Claims] 1. An optical waveguide and an optical fiber are respectively fixed to a metallic optical waveguide block and an optical connector block, and a flange portion is provided at least at a connection end portion of the one block, and the flange portion and the other block are provided. A coupling structure of an optical waveguide and an optical fiber, characterized in that the abutting portions are fixed to each other by abutting. 2. The coupling structure for an optical waveguide and an optical fiber according to claim 1, wherein the butting portion between the flange portion and the other block is fixed by YAG laser welding.