JPH05224079A - Coupling structure of optical waveguide path and optical fiber - Google Patents

Abstract

PURPOSE:To make the constitution of an optical waveguide path base body lower in cost and superior in transmission characteristics, in the structure that the optical waveguide path base body and an optical fiber holding member are positioned via a guide pin and are coupled optically. CONSTITUTION:The optical waveguide path base body 13 is composed of a combination of a first base body 13a having an optical waveguide path 12 and being formed using a LiNbO3 crystal, and a second substrate 13b having a groove 16 for guide pin on the upper surface and being formed using Si. An optical fiber 8 and the guide pin 17 are clamped via V shaped grooves 14, 20 at the abutting surface of an upper side plate 18 and a lower side plate 19 which constitute the optical fiber holding member 11, and non-aligning mounting of the optical waveguide path 12 and the optical fiber 8 is carried out by being engaged the guide pin 17 with the groove 16 for guide of the optical waveguide path base body 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coupling structure between an optical waveguide formed on an optical waveguide substrate and an optical fiber.

[0002]

2. Description of the Related Art In order to make an optical signal enter or exit an optical waveguide, it is necessary to connect an end face of an optical fiber to an end face of the optical waveguide. Since this optical connection requires a high accuracy of 0.1 μm, it takes a lot of time to align the optical waveguide and the optical fiber at the time of connection, resulting in poor work efficiency. For this reason, various improvements have been made in the past, and for example, JP-A-63-278471 of the present applicant is known.

In the coupling structure of an optical waveguide and an optical fiber according to this Japanese Patent Laid-Open Publication No. Sho.
Is to combine. In this optical coupling structure, the optical fiber holding member 1 is composed of the upper plate 4 and the lower plate 5, and the optical fiber 8 and the guide pin 7 held by the two V grooves 6 and 10 formed on the joint surfaces of both plates. It is configured.

The optical fiber 8 is constructed so as to be optically coupled to the end face of the optical waveguide 2 when the optical fiber holding member 1 is mounted on the optical waveguide substrate 3. In this case, the positioning of the optical fiber 8 in the Z direction is performed by the lower surface 4a of the upper plate 4,
This is done by contact with the upper surface 3a of the optical waveguide substrate 3. Further, the positioning of the optical fiber 8 in the X direction (optical axis direction) is performed by bringing the front surface of the lower plate 5 of the optical fiber holding member 1 into contact with the side surface 3b of the optical waveguide substrate 3. Further, the positioning of the optical fiber 8 in the Y direction is performed by the upper plate 4 and the lower plate 5 of the optical fiber holding member 1.
The guide pins 7 held in the V-shaped grooves 10 and 10a formed facing the contact surface of the optical waveguide substrate 3 on the upper surface of the optical waveguide substrate 3.
And is formed in parallel with the V-shaped guide pin groove 9 formed in parallel.

According to the above-described optical waveguide / optical fiber coupling structure, the guide pin 7 mounted on the optical fiber holding member 1 is engaged with the guide pin groove 9 of the optical waveguide substrate 3, and the optical fiber holding member 1 is further provided. By contacting the two surfaces of the optical waveguide substrate 3 with the two surfaces of the optical waveguide substrate 3, the input / output ends of the optical waveguide 2 formed in the optical waveguide 3 and the optical fiber 8 can be mounted without alignment.

[0006]

The present inventor has conducted the research to further improve the above-mentioned coupling structure between the optical waveguide and the optical fiber, and has encountered the following problems. That is, LiNbO ₃ (lithium niobate) crystal is generally used as the material of the optical waveguide substrate 3. Although this LiNbO ₃ crystal is very expensive, since the guide pin groove 9 is formed on the upper surface of the optical waveguide substrate 3, the optical waveguide substrate 3 becomes large. Therefore, LiNbO ₃
There is a drawback that the size of the crystal becomes large and the cost increases. Further, depending on the LiNbO ₃ crystal, it was fragile, and it was difficult to form the guide pin groove 9 in the optical waveguide substrate 3.

It is an object of the present invention to provide a coupling structure for an optical waveguide and an optical fiber, which has improved the above drawbacks.

[0008]

SUMMARY OF THE INVENTION According to the present invention, an optical waveguide and an optical fiber are formed by positioning an optical waveguide substrate and an optical fiber holding member through a guide pin and coupling the optical fiber to an end face of the optical waveguide. In the coupling structure of 1., the optical waveguide substrate comprises a first substrate on which the optical waveguide is formed, and a second substrate formed of a material different from that of the first substrate and having the first substrate mounted thereon. However, the first substrate and the second substrate are flattened by surface polishing, and a groove for a guide pin is formed in the second substrate.

The above-mentioned first substrate is formed of LiNbO ₃ crystal, and the second substrate is formed of Si material.

[0010]

The first substrate is made of a material such as LiNbO ₃ crystal which is expensive but is optimal for forming an optical waveguide. The second substrate holds the first substrate and For example, Si suitable for forming the guide pin groove can be used. Moreover, the optical fiber can be optically coupled to the end face of the optical waveguide by a simple operation by coupling the optical waveguide base made of the combination of the first and second substrates and the optical fiber holding member via the guide pin.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a perspective view of an optical waveguide substrate 13 and an optical fiber holding member 11 according to the present invention, and FIGS. 2A, 2B, 2C and 3 are shown.
8A, 8B and 8C are perspective views showing the manufacturing process of the optical waveguide substrate 13.

In FIG. 1, an optical waveguide substrate 13 has a first substrate 13a having an optical waveguide 12, and a guide pin groove 1
It is configured by combining and coupling the second substrate 13b having 6 together. Moreover, the first substrate 13a and the second substrate 13a
Since different materials are used for the substrate 13b, the first substrate 13a is expensive and fragile in strength, but it is an optimal material for forming the optical waveguide 12.
iNbO ₃ crystals have been used. The second substrate 13b instead of expensive than LiNbO _3, also good workability in manufacturing the guide pin grooves 16, moreover the Si that can be expected improvement of the machining accuracy are used.

The first substrate 13a and the second substrate 13b
A process of manufacturing the optical waveguide substrate 13 by combining the above will be sequentially described with reference to FIGS.

First, as shown in FIG. 2A, a cutter blade (not shown) is used at the center of the upper surface of a rectangular second base material 13b made of a Si material having a width of 10 mm, a length of 30 mm and a thickness of 2 mm. The recessed groove 20 having a predetermined width is counterbored. Next, as shown in FIG. 2B, the groove 20 has a width of 3 mm and a length of 30 mm.
mm made of LiNbO ₃ crystal with a thickness of 0.5 mm
The substrate 13a is attached. Thereafter, as shown in FIG. 2C, the surface of each substrate 13b is flattened. After that, FIG.
As shown in A, the groove 16 for inserting the guide pin is cut on the second substrate 13b. Further, as shown in FIG. 3B,
The optical waveguide 12 is produced on the LiNbO ₃ crystal that is the second substrate 13b by the Ti diffusion method to produce the optical waveguide base 13.

Optical waveguide substrate 1 produced as described above
3, the optical fiber holding member 11 is coupled to the optical waveguide 12
The optical fiber 8 can be optically coupled to the end face of the. (Refer to FIG. 1) The optical fiber holding member 11 is the upper plate 1 formed of a silicon chip or plastic as in the conventional case.
8 and the lower plate 19 are joined together, and the upper plate 18 is provided longer than the lower plate 19. The V groove 20 for the optical fiber and the groove 1 for the guide pin facing the contact surfaces of the upper plate 18 and the lower plate 19
4 are formed. Then, the optical fiber 8 from which the outer cover 8a is peeled off is clamped and fixed in the V groove 20 and the guide pin 17 is clamped and fixed in the guide pin groove 14.

By coupling the above-mentioned optical fiber holding member 11 to the end of the optical waveguide base 13, the optical fiber 8 can be coupled to the end face of the optical waveguide. In this case, as in the conventional case, the lower surface of the upper plate 18 is brought into contact with the upper surface of the optical waveguide substrate 13 to position the optical fiber 8 in the upward direction in FIG. In addition, by bringing the front end face of the lower plate 19 into contact with the end face of the optical waveguide body 13,
Is positioned in the optical axis direction. Further, by engaging the guide pin 17 with the guide pin groove 16, the optical fiber 8 can be positioned in the lateral direction. In this way, in the present embodiment as well, the guide pin 17 is engaged with the guide pin groove 16 to couple the optical waveguide base 13 and the optical fiber holding member 11 to each other, whereby the optical waveguide 1 is non-aligned.
2 and the optical fiber 8 can be mounted.

[0018]

As described above, according to the present invention, the optical waveguide substrate is composed of the combination of the first substrate and the second substrate. Therefore, each substrate should be made of a different material. It is possible to construct an optical waveguide substrate that is most advantageous in terms of cost and transfer characteristics. Especially,
The first substrate forming the optical waveguide is expensive and brittle,
For the guide pin for positioning the optical waveguide base and the optical fiber holding member at a low cost on the second substrate while forming it to the minimum necessary size by using the optimal LiNbO ₃ crystal for forming the optical waveguide. It is possible to construct an optical waveguide substrate by using Si, which can easily and accurately process the groove of, and attach the first substrate to the second substrate. Therefore, an inexpensive and high-performance optical waveguide and optical fiber can be formed. It is possible to realize a coupling structure with.

[Brief description of drawings]

FIG. 1 is a perspective view of a coupling structure of an optical waveguide and an optical fiber according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which an optical waveguide is manufactured by pasting a first substrate on a second substrate.

FIG. 3 is a perspective view showing a state in which a guide pin groove and an optical waveguide are formed on a second substrate and a first substrate, respectively, to produce an optical waveguide.

FIG. 4 is a perspective view showing a conventional coupling structure of an optical waveguide and an optical fiber.

[Explanation of symbols]

8 ... Optical fiber, 11 ... Optical fiber holding member, 12 ... Optical waveguide, 13 ... Optical waveguide base, 13a ... First substrate, 1
3b ... 2nd base | substrate, 16 ... Groove for guide pins, 17 ... Guide pin, 18 ... Upper plate, 19 ... Lower plate.

Claims (2)

[Claims] 1. A coupling structure of an optical waveguide and an optical fiber, wherein the optical waveguide substrate and the optical fiber holding member are positioned via a guide pin and the optical fiber is coupled to an end face of the optical waveguide. The substrate comprises a first substrate having an optical waveguide and a second substrate made of a material different from that of the first substrate and having the first substrate mounted thereon. The coupling structure of an optical waveguide and an optical fiber, wherein the second substrate is flattened by surface polishing, and a groove for a guide pin is further formed in the second substrate. 2. The optical waveguide and the optical fiber according to claim 1, wherein the first substrate is made of LiNbO ₃ crystal and the second substrate is made of Si. Bond structure.