JPH05257033A - Structure of joining part between optical waveguide and optical fiber - Google Patents

Abstract

PURPOSE:To prevent connection loss from being generated owing to the rubbing between an optical waveguide end surface and an optical fiber end surface when the optical waveguide and optical fiber are optically connected. CONSTITUTION:The waveguide substrate 3 of the optical waveguide 2 and the connectors 4 and 5 of the optical fiber are attached on holders 6, 7 and 8. Further, the end surface 3a of the waveguide substrate 3 is arranged at a position which is specific size L recessed from the end surface 6a of the holder 6. The size L from this holder end surface 6a to the end surface 3a of the optical waveguide 3 is set to 5-50mum. Further, the end surfaces 6a, and 7a and 8a of the respective holders 6, 7 and 8 of the waveguide substrate and optical fiber 10 are fixed together by welding or adhesion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for joining an optical waveguide and an optical fiber in an optical waveguide component manufactured by laser welding or adhesively fixing an optical waveguide holder and an optical fiber holder.

[0002]

2. Description of the Related Art In recent years, with the development of technology in the technical fields of optical communication and optical information processing, an optical fiber for single mode transmission (hereinafter abbreviated as single mode fiber), an optical coupling circuit and an optical branching circuit. It is earnestly desired to mount the optical waveguides that compose the above with high reliability. in this case,
Since the core diameter of the single-mode fiber is about several μm to 10 μm, when connecting the single-mode optical fiber and the optical waveguide, the relative positional deviation between them is suppressed to about 1 μm or less to reduce the connection loss. It is necessary to prevent the increase.

Conventionally, when splicing an optical waveguide and a single-mode optical fiber, a holder for holding the optical waveguide so that the splice loss is minimized by aligning relative positions while monitoring the splice loss thereof. And position each abutting surface of the holder that holds the optical fiber by butting
This butted portion is fixed by an adhesive or laser welding.

Referring to FIG. 5, the optical waveguide component 1 is constructed by disposing optical connectors 4 and 5 to which optical fibers are connected on both sides of a waveguide substrate 3 having an optical waveguide 2. .. The optical waveguide substrate 3 is mounted on a stainless steel substantially U-shaped waveguide holder 6, and the optical connectors 4 and 5 are respectively mounted on a substantially U-shaped optical connector holders 7 and 8 having a stainless steel bottom surface. ..

In one optical connector 4, a single mode optical fiber 10 with an outer cover 9 peeled is embedded. To the other optical connector 5, the connection ends of a plurality of single-mode optical fibers 10 from which the outer cover 9 is peeled off are connected.
Then, the optical waveguide substrate 3 and the abutting ends 11 of the holders 6, 7, and 8 of the optical connectors 4 and 5 are spot-welded with a YAG (yttrium-aluminum-garnet) laser as appropriate and integrated with each other.

The light incident from the one optical fiber 10 is branched into eight in the optical waveguide 2, and eight optical fibers 1 are provided.
0 is transmitted.

[0007]

In the conventional optical waveguide component shown in FIG. 5, the end face 2a of the optical waveguide 2 and the end face 6a of the holder 6 holding the end face 2a, or the optical fiber 1 is used.
The end surface 10a of 0 and the end surfaces 7a and 8a of the holders 7 and 8 holding it are substantially in the same plane. Therefore, in the relative alignment between the optical waveguide 2 and the optical fiber 10, the end faces 2 of the optical waveguide 2 and the optical fiber 10 are aligned.
When the positions of a and 10a are adjusted while they are in contact with each other, there has been a situation in which the optical junction parts of the parts are worn and scratched, causing deterioration of the connection loss.

[0008]

SUMMARY OF THE INVENTION According to the present invention, an optical waveguide having an optical waveguide substrate and an optical fiber connector supporting an optical fiber are mounted on a holder, respectively, and end faces of the holders are fixed to each other. In the joint structure of the optical waveguide and the optical fiber, at least one of the end face of the waveguide substrate and the end face of the optical fiber connector is arranged at a position retracted from the contact end face of the holder. The dimension from the contact end face to the retracted position is preferably set in the range of 5 to 50 μm.

[0009]

When performing relative alignment between the optical waveguide and the optical fiber, at least one of the end face of the waveguide substrate and the end face of the optical fiber connector is arranged at a position retracted from the contact surface between the holders. Therefore, the optical joint between the optical waveguide and the optical fiber is not worn or damaged.

[0010]

Embodiments of the present invention will be described below with reference to FIGS. The same elements as those of the conventional example will be described with the same reference numerals.

As shown in FIG. 1, the connection end of the single-mode optical fiber 10 on the light incident side, which is covered with the jacket 9, is embedded in the first optical fiber connector 4 with the jacket 9 removed. The optical fiber connector 4 is attached to the holder 7. The optical waveguide 2 connected to the optical fiber 10 supported by the optical fiber connector 4 is opposed to the optical fiber connector 4. The optical waveguide 2 is formed on a waveguide substrate 3, and the waveguide substrate 3 is mounted on a holder 6. The optical waveguide 2 is a Y branch circuit that is branched into eight. The other end of the optical waveguide 2 is connected to the connection end of the single mode optical fiber 10 held by the second optical fiber connector 5, and the optical fiber connector 5 is mounted on the holder 8. ing.

In the above structure, the end surfaces 3a on both sides of the waveguide substrate 3 are arranged at positions recessed from the end surface 6a of the holder 6 by a predetermined dimension L. The dimension L of the recess 12 is preferably set in the range of 5 to 50 μm. In addition, the refractive index matching grease 11 is provided in the recess 12.
To fill the end face 2a of the optical waveguide 2 and the optical fiber 10
The surface reflection at the end face 10a of the is suppressed. In addition, instead of the refractive index matching grease 11, the end face 2 of the optical waveguide 2
An antireflection coat may be applied to a.

Next, the operation of the present invention will be described.

The holder 6 of the waveguide substrate 3 and the optical fiber 10
When the end faces 6a, 7a, 8a of the holders 7, 8 are brought into contact with each other to perform the relative alignment between the optical waveguide 2 and the optical fiber 10, the end face 3a of the waveguide substrate 3 recedes from the end face 6a of the holder 6. Since the optical waveguide 2 is arranged at such a position, the end face 2a of the optical waveguide 2 and the end face 10a of the optical fiber 10 do not come into contact with each other, and the optical junction is not worn or damaged, so that the connection loss is not deteriorated. Moreover, the dimension L of the recessed portion 12 is set to 5 to 50.
Since it is provided in the range of μm, the increase of the coupling loss due to the provision of the recess 12 can be suppressed to less than about 0.2 dB.

This will be described with reference to FIGS. 3 and 4. The optical fiber 10 of FIG. 3 is surrounded by the clad 10c and the core 10b of which the diameter dimension a [μm] is 10 μm and the clad 2c of the optical waveguide 2. When the cores 2b are coupled at a spacing of d [μm], the relationship between the coupling loss and the spacing dimension is shown in FIG.
become that way. It can be seen from FIG. 4 that the coupling loss becomes 0.2 dB when the spacing is 50 μm. Therefore, it is understood that it is preferable to set the recessed portion of the end surface 2a of the optical waveguide 2 in this embodiment within the range of 5 to 50 μm.

The inventors of the present invention have made a prototype of the product according to the embodiment, which will be described below. An optical waveguide having a 1 × 8 branch structure shown in FIG. 1 was formed on a waveguide substrate, and both end faces of this waveguide substrate were polished in advance and cut so that they could be attached to a separately prepared optical waveguide holder. The holder was processed so that its total length was longer than that of the waveguide substrate by about 20 μm.

The waveguide substrate mounting holder thus manufactured was aligned with the optical fiber holder by the method shown in FIG. At that time, matching oil was filled in the gap between the waveguide substrate and the optical fiber connector. In the process of this alignment, the optical waveguide core and the optical fiber core do not come into contact with each other, the optimum coupling position can be searched for smoothly, and a low coupling loss optical waveguide / optical fiber coupling component is obtained. I was able to do it.

In the above embodiment, the end face 3a of the waveguide substrate 3 is recessed from the end face 6a of the holder 6 by a predetermined dimension L. However, in contrast to this, the first and second light beams are inverted. The end faces 4a, 5a of the fiber connectors 4, 5 are attached to the holders 7,
Alternatively, the end faces 7a, 8a of 8 may be recessed by a predetermined dimension (not shown). In this case, the end face 3a of the waveguide substrate 3 and the end face 6a of the holder 6 are provided on the same plane.

[0019]

As described above, according to the present invention,
When aligning the waveguide substrate and the optical fiber connector, which are respectively mounted on the holders, the end faces of the optical waveguide and the end faces of the optical fibers do not come into contact with each other so that they are not worn and deteriorated. This makes it possible to manufacture a highly accurate optical waveguide / optical fiber connection component.

[Brief description of drawings]

FIG. 1 is an explanatory plan view according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the optical waveguide and its holder of FIG. 1 in a separated state.

FIG. 3 is an enlarged explanatory diagram showing a connection relationship between an optical fiber and an optical waveguide.

FIG. 4 is a graph showing a distance between an end face of an optical waveguide and an end face of an optical fiber and a coupling loss.

FIG. 5 is an explanatory plan view showing a conventional joint structure between an optical waveguide and an optical fiber.

[Explanation of symbols]

1 ... Optical waveguide component, 2 ... Optical waveguide, 3 ... Waveguide substrate, 4
… Optical fiber connector, 5… Optical fiber connector, 6…
Holder, 7 ... Holder, 8 ... Holder, 10 ... Optical fiber,
12 ... Recessed part.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masahide Saito 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works (72) Tatsuhiko Saito 1 Taya-cho, Sakae-ku, Yokohama, Kanagawa Sumitomo Electric Industry Co., Ltd. Yokohama Works

Claims (2)

[Claims] 1. A waveguide substrate on which an optical waveguide is formed and an optical fiber connector supporting an optical fiber are mounted on a holder, respectively, and an end face of each holder is fixed to the optical waveguide and the optical fiber. In the joint structure, at least one of the end face of the waveguide substrate and the end face of the optical fiber connector is arranged at a position retracted from the contact end face of the holder. Part structure. 2. The dimension from the contact end face to the retracted position is 5 to 50 μm.
The structure of the joint between the optical waveguide and the optical fiber described in.