JPH03182703A - Coupling method for planar optical waveguide and optical fiber and auxiliary coupling device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of coupling a planar optical waveguide to an optical fiber and a coupling auxiliary device. More specifically, the present invention relates to a method and an auxiliary device that make it possible to easily couple a planar optical waveguide and an optical fiber with fewer alignment operations.

BACKGROUND OF THE INVENTION A method of coupling a planar optical waveguide and an optical fiber using a conventional coupling auxiliary device will be described with reference to FIGS. 6 and 7.

The conventional coupling auxiliary device shown in FIG. 6 is comprised of a connector 11 that holds two optical fibers 5 at equal intervals to two planar optical waveguides 3 formed on a substrate 2. In this device, two optical fibers 5 held by a connector 11
are connected at the end surface of the substrate 2. In this case, x as the alignment axis
, y, and z axes, rotations θ8, θ9, and θ2 are added, and alignment of six axes at one end is required.

On the other hand, FIG. 7 shows an auxiliary device for coupling a planar optical waveguide and an optical fiber, which is disclosed in Japanese Patent Application No. 63-310739 filed on December 8, 1988 by the present applicant. In this device, a substrate 2 on which a planar optical waveguide is formed is mounted so that the surface on which the planar optical waveguide is formed is in contact with a mounting surface 1a, and is fixed with a holding plate 12, and a connector 11 holding an optical fiber 5 is connected to the It mainly consists of a base 1 which is fixed so that the optical axis of the fiber 5 is on the same plane as the optical axis of the planar optical waveguide.

Using this device, the optical axis of the optical fiber and the optical axis of the planar optical waveguide are arranged on the same plane, reducing the number of alignment axes, but it is still necessary to perform alignment within that plane. Ta.

Problems to be Solved by the Invention As mentioned above, when conventional coupling auxiliary devices are used, complicated alignment work is required. Also, the seventh
In the device shown in the figure, a substrate 2 on which a planar optical waveguide is formed is placed on a base 1.
When fixing the substrate 2 to the base 1, the substrate 2 and the base 1 may not be in complete contact with each other. Therefore, the optical axis of the optical fiber and the optical axis of the planar optical waveguide may not match, resulting in connection loss.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a method and a coupling auxiliary device for coupling a planar optical waveguide and an optical fiber without requiring complicated alignment work and without causing connection loss. Our goal is to provide the following.

Means for Solving the Problems According to the present invention, a planar optical waveguide formed on a substrate;
In a method for determining the positions of optical fibers when optically coupling and fixing them, the optical fiber is fixed to an optical fiber holder, and the optical axis of the optical fiber is at a predetermined position and in a predetermined direction. Place the optical fiber holder on a guide groove formed on the base so that the optical fiber holder can be placed thereon, and guide the optical fiber so that the center of the optical fiber and the optical axis of the planar optical waveguide are on the same plane. There is provided a method characterized in that the substrate on which the planar optical waveguide is formed so that it can be held by a groove is held by the guide groove and the position is determined.

Further, in the present invention, in an apparatus for positioning an optical fiber fixedly held in an optical fiber holder and a planar optical waveguide when optically coupling the two, when the optical fiber holder is placed, the optical fiber is A planar light guide is provided with a guide groove formed in a base so that the optical axis of the fiber is at a predetermined position and in a predetermined direction, and a part of the guide groove is processed to have a complementary shape. A planar optical waveguide and an optical waveguide, characterized in that the center of the optical fiber and the optical axis of the planar optical waveguide are on the same plane when a substrate on which a waveguide is formed is held in the guide groove. A fiber coupling aid is provided.

In one embodiment of the device of the present invention, the guide groove has a cross section of 9
It is preferable to make it into a letter shape.

Operation In the method of the present invention, an optical fiber is fixed to an optical fiber holder and placed in a guide groove in which the optical axis of the optical fiber is at a predetermined position and in a predetermined direction. Then, the substrate on which the planar optical waveguide is formed is processed so that it can be held by the guide groove so that the center of the optical fiber and the optical axis of the planar optical waveguide are on the same plane, and the planar optical waveguide is held on the guide groove. The main feature is that the optical fibers are positioned and coupled.

Further, the device of the present invention has a guide groove formed in the base so that the optical fiber holder holding the optical fiber fixedly is placed so that the optical axis of the optical fiber is at a predetermined position and in a predetermined direction. Be equipped. Then, when a substrate on which a planar optical waveguide processed into a shape matching this guide groove is formed is held by the guide groove, the center of the optical fiber and the optical axis of the planar optical waveguide are on the same plane. is the main feature.

In the device of the present invention, for example, the guide groove has a V-shaped cross section, and the optical fiber holder has a cylindrical shape to hold the optical fiber at the center. The optical fiber holder is configured such that when the optical fiber holder is placed in the guide groove, the optical axis of the optical fiber held at the center becomes parallel to the guide groove on the base surface.

Further, the substrate on which the planar optical waveguide is formed is processed so that both side surfaces parallel to the planar optical waveguide are sloped to match the V-shape of the guide groove. That is, the cross section of the substrate perpendicular to the planar optical waveguide is made to be an isosceles trapezoid.

A planar optical waveguide is provided on the long base side of the isosceles trapezoid, so that when the substrate is placed in the guide groove, the surface of the base and the surface of the substrate on which the planar optical waveguide is formed are on the same plane.

By configuring the apparatus of the present invention as described above, the optical axes of the optical fiber and the planar optical waveguide can be aligned by simply performing alignment work. Therefore, when the apparatus of the present invention is used, the efficiency of the coupling operation between an optical fiber and a planar optical waveguide is greatly improved.

In the method of the present invention, the above-described apparatus is used to process a substrate on which a planar optical waveguide is formed into a predetermined shape and hold it on a guide groove. Further, an optical fiber holder holding an optical fiber fixed thereon is placed on the guide groove holding the substrate. In this state, the optical axis of the planar optical waveguide and the geometric center of the optical fiber are on the same plane. In a single-core optical fiber, the geometric center of the optical fiber and the optical axis coincide, so in this state, the optical axis of the planar optical waveguide and the optical axis of the optical fiber coincide. Furthermore, in the case of multicore optical fibers, by rotating the optical fiber holder on the guide groove, the optical axis of each planar optical waveguide and the optical axis of the optical fiber can be aligned.

Therefore, with the method of the invention, the alignment work is greatly simplified. When the optical axis of the planar optical waveguide and the optical axis of the optical fiber match, the substrate on which the planar optical waveguide is formed and the optical fiber or optical fiber holder are fixed with resin or the like, and the planar optical waveguide and optical fiber are connected. are optically coupled and fixed.

Once the planar optical waveguide and optical fiber are fixed, both can be removed from the guide groove. It is also possible to remove the optical fiber holder if necessary.

As described above, by using the device of the present invention and following the method of the present invention, a planar optical waveguide and an optical fiber can be easily coupled.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the following disclosure is merely an example of the present invention and does not limit the technical scope of the present invention in any way.

Embodiment FIG. 1 shows how optical fibers 5 are coupled to both ends of a planar optical waveguide 3 using the apparatus of the present invention. In FIG. 1, a substrate 2 on which a planar optical waveguide 3 is formed is placed approximately at the longitudinal center of a groove 6 with a V-shaped cross section formed in a base l, and the surface on which the planar optical waveguide 3 is formed is It is held facing upward. In front and behind the substrate 2 held in the V-shaped groove 6, cylindrical optical fiber holders 4, which fixedly hold the optical fiber 5 at the center, are placed in contact with the substrate 2.

In this state, the optical axis of the planar optical waveguide 3 and the optical axis of each optical fiber 5 are configured to match, and the planar optical waveguide 3 and the optical fibers 5 are coupled and fixed by fixing with resin or the like. can do.

As described above, once the planar optical waveguide 3 and the optical fiber 5 are coupled and fixed, the planar optical waveguide 3 and the optical fiber 5 can be removed from the V-shaped groove 6. Furthermore, the optical fiber holder 4 can be removed if necessary.

FIGS. 2(a) and 2(b) show a planar optical waveguide 3, respectively.
1 shows a front view and a perspective view of a substrate 2 on which is formed.

In this example, LiNbO2 was used for the substrate 2, and the planar optical waveguide 3 was formed at the center of the surface by thermally diffusing T1. Furthermore, side surfaces 9.90 of the substrate 2 parallel to the planar optical waveguide 3 were polished obliquely to match the V-shaped grooves 6 of the base 1.

FIGS. 3(a) and 3(a) show conceptual diagrams when fixing the optical fiber 5 to the optical fiber holder 4. A fiber insertion hole 41 is provided at the center of the optical fiber holder 4, into which the fiber 5 is inserted. After the fiber 5 is inserted, it is fixed with resin or the like and polished together with the end surface 42 of the optical fiber holder 4.

In FIG. 4(a), V formed on the base 1 of the first fffl
A cross section of the groove 6 is shown. In this embodiment, the angle α of the V-shaped groove 6 is
was set at 90°, and the maximum width (upper end) was set at 3 mm.

In FIG. 4(b), the substrate 2 on which the planar optical waveguide 3 is formed is
It shows how it is held in the groove 6. As shown in FIG. 4(b), the substrate 2 is held so that its center coincides with the center of the V-shaped groove 6 and the surface on which the planar optical waveguide 3 is formed is flush with the surface of the base l. . Figure 4(C) shows the optical fiber 5.
The optical fiber holder 4, which is held at the center, is shown being placed in the V-shaped groove 6. As shown in FIG. 4(C), the optical fiber holder 4 is placed so that the core 7 of the optical fiber 5 held at the center is on the same plane as the surface of the base 1 at the center of the V-shaped groove 6. Ru.

FIG. 5(a) shows how the substrate 2 on which the planar optical waveguides 31 and 32 are formed is held in the V-shaped groove 6 of the base 1, and FIG. 5(b) shows how the two optical fibers are connected. Optical fiber holder 4 holds 51 and 52 in the center and fixed with resin 10
is shown being placed in the V-shaped groove 6 of the base 1. The planar optical waveguides 31 and 32 are formed symmetrically with respect to the center line at least near both ends of the substrate 2. Also,
The distance between the optical axes of the optical fibers 51 and 52 is equal to the distance between the optical axes of the planar optical waveguides 31 and 32.

In the case of FIG. 5(a), the center of the substrate 2 coincides with the center of the V-shaped groove 6, and the planar optical waveguide 3
The surface on which 1 and 32 are formed is held flush with the surface of the base 1. In addition, in the case of the 5th Kaizan),
The midpoint of the line segment connecting the cores 71 and 72 of the two optical fibers 51 and 52 is the center of the V-shaped groove 6, and the cores 71 and 72 of the optical fibers 51 and 52 are on the same plane as the surface of the base 1. Optical fiber holder 4 so that it is on top
is placed.

In the device of the present invention, the substrate 2 on which the two planar optical waveguides 31 and 32 are formed and the optical fiber holder 4 that fixedly holds the two optical fibers 51 and 52 are arranged as described above. Ru. Therefore, by simply rotating the optical fiber holder 4, the planar optical waveguide 3132 and the optical fiber 51.
It is possible to align with 2.

Although this embodiment shows a case where the surface on which the planar optical waveguide is formed is on the same plane as the upper surface of the base, the configuration of the device of the present invention is not necessarily limited to this. That is, when the substrate on which the planar optical waveguide is formed is held and the optical fiber holder is also placed on the guide groove of the base, the optical axis of the planar optical waveguide and the optical axis of the optical fiber coincide. Both may be arranged in any manner as long as they are configured as follows.

Effects of the Invention As detailed above, by using the auxiliary device of the present invention, it becomes possible to easily couple a planar optical waveguide and an optical fiber with high precision.

This is because, due to the unique configuration of the device of the present invention, the optical axis of the planar optical waveguide and the center of the optical fiber are on the same plane without alignment work.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of the state in which the planar optical waveguide and optical fiber coupling auxiliary device of the present invention are used, and FIG. 2(a)
3A and 3B are a front view and a perspective view of an example of a substrate on which a planar waveguide used in the device of the present invention is formed, and FIGS. FIG. 4(b) is a conceptual diagram showing a state when an optical fiber is fixed to an example of a fiber holder; FIG. 4(a) is a sectional view of an example of a guide groove of the device of the present invention; FIG. 4(C) is a cross-sectional view of a substrate on which a planar waveguide is formed is held in an example of the guide groove of the device of the present invention, and FIG. FIG. 5(a) is a cross-sectional view of a state in which an optical fiber holder that fixedly holds an optical fiber is placed, and FIG. FIG. 5(b) is a cross-sectional view of a state in which a substrate is held, and FIG. FIG. 6 and FIG. 7 are perspective views of a conventional coupling auxiliary device for a planar optical waveguide and an optical fiber. [Main reference numbers] 1. Base, 2. Substrate, 3. Planar optical waveguide, 4. Optical fiber holder, 5. Optical fiber, 6. V-groove, 7. Core,
10... Resin, 11... Connector, 12... Holding plate

Claims (3)

[Claims] (1) In a method of optically coupling and fixing a planar optical waveguide formed on a substrate and an optical fiber, the optical fiber is fixed to an optical fiber holder, and the optical axis of the optical fiber is positioned at a predetermined position. The optical fiber holder is placed on a guide groove formed on a base so that the optical fiber holder can be placed in a predetermined direction, and the center of the optical fiber and the optical axis of the planar optical waveguide are on the same plane. A method for coupling a planar optical waveguide and an optical fiber, characterized in that a substrate on which the planar optical waveguide is formed so that it can be held by the guide groove is held by the guide groove to determine the position. (2) In a device that positions an optical fiber fixedly held in an optical fiber holder and a planar optical waveguide formed on a substrate when optically coupling and fixing both, the optical fiber holder is placed A guide groove is formed on the base so that the optical axis of the optical fiber is at a predetermined position and in a predetermined direction when the optical fiber is placed in a predetermined direction. characterized in that when the processed substrate on which the planar optical waveguide is formed is held in the guide groove, the center of the optical fiber and the optical axis of the planar optical waveguide are on the same plane. An auxiliary device for coupling a planar optical waveguide and an optical fiber. (3) A coupling auxiliary device for a planar optical waveguide and an optical fiber, wherein the guide groove has a V-shaped cross section.