JPH11190810A - Method and device for connecting optical waveguide and optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the method and device for connecting a flexible optical waveguide which has small connection loss and is small-sized, lightweight, superior in operability, and high in reliability to an optical fiber. SOLUTION: The end surface of the optical waveguide 10 with a core and a clad which is perpendicular to the light propagation direction is machined into a convex shape having its peak in the center of the core 11 and the end surface of the optical fiber 14 is pressed and connected to the convex shape part. This connecting device is equipped with a substrate 16 where the optical waveguide and a microcapillary are arrayed and fixed where the center of the optical waveguide 10 having the end surface of its core 11 machined into the convex shape having its peak in the center of the core is aligned with the center axis of the microcapillary 16 and a plug where the optical fiber having an external diameter a little less than the internal diameter of the microcapillary is arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for connecting an optical waveguide to an optical fiber and a connecting device therefor.

[0002]

2. Description of the Related Art As a conventional technique relating to the connection between an optical waveguide and an optical fiber, for example, a paper by Asakawa et al. A technique for manufacturing a connector by connecting a PC (Physical Contact) with a PC has been reported. FIG. 1 is a cross-sectional view showing an example of a PC connection between a silica-based optical waveguide and an optical fiber described in this report.

In the figure, a quartz optical waveguide 1 formed on a Si substrate 2 is provided with a glass block 3 for connection reinforcement, and a precision glass sleeve 4 is provided on an end face as a fiber alignment member. The core is aligned and attached to the core end face. The inner diameter of the glass sleeve 4 is the optical fiber 5
Since the diameter is larger than the outer diameter by 1 μm and the opening is tapered, the optical fiber 5 can be inserted smoothly. The outer peripheral portion of the end face of the optical fiber 5 is chamfered to further facilitate insertion. Optical fiber 5
Is buckled by being pressed against the end face of the waveguide as shown in FIG. With this buckling pressure, a stable PC connection is obtained between the optical fiber and the waveguide. In the figure, reference numeral 6 denotes a fixing member.

On the other hand, in order to enhance the connectivity between a soft and flexible optical waveguide and an optical fiber, for example, Japanese Unexamined Patent Publication No. 8-43652 discloses that a flexible embedded optical waveguide has a substantially cylindrical end formed in a core unit. There has been proposed a method of separating them. FIG. 2 is a diagram showing the shape of the optical waveguide in the proposal, and the end 8 of the flexible optical waveguide 7 is shown.
Are processed into a substantially cylindrical shape in core units. In the figure, reference numeral 9 denotes a core of the optical waveguide. This proposal intends to improve the matching with the optical fiber by processing the end 8 of the embedded optical waveguide into a shape similar to the optical fiber, and to increase the degree of freedom in connection and mounting.

[0005]

However, when the optical waveguide is made of a material softer than quartz, for example, an organic material, in the case of PC connection, an optical fiber is connected to the optical waveguide end face 7 as shown in FIG. 5 is pressed, the optical waveguide 7 is dented, and there is a problem that PC connection cannot be realized. In the case of processing the end of the optical waveguide into a substantially cylindrical shape, if the processed end of the optical waveguide has the same size and shape as the optical fiber, the connection can be made in accordance with the connection between the optical fibers. Yes, but such connections are not possible if they differ in size or shape. For this reason, the end of the optical waveguide must be processed with extremely high precision, but there is a problem that it is extremely difficult to precisely process the end into a cylindrical shape.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a flexible connection method between a flexible optical waveguide and an optical fiber, and a connection device therefor, which has a small connection loss, is small, lightweight, has excellent workability, and has high reliability. It is in.

[0007]

In order to achieve the above object, a method for connecting an optical waveguide and an optical fiber according to the present invention is characterized in that an end face perpendicular to the light propagation direction of the optical waveguide has a convex shape with the center of the core as the vertex. And the end face of the optical fiber is pressed against and connected to the convex portion.

According to the connection method of the present invention, the end face of the core of the optical waveguide having the core and the clad is processed into a convex shape with the center of the core as the vertex, so that the optical fiber is pressed against the core end face of the optical waveguide. At the time of connection, the adhesion between the core end face and the optical fiber is ensured, and a highly reliable connection method with small loss can be realized. At this time, not only is the shape of the core end face easily adhered to the optical fiber, but also the core end face has an effect of being slightly deformed by pressing from the optical fiber, and high adhesion can be secured. For this reason, it is effective to make the convex shape of the core end surface into a tapered shape or a smooth curved shape.
If the width of such a protruding portion is larger than the core of the optical fiber and the optical waveguide and smaller than the outer diameter of the optical fiber, the purpose is achieved, so that precise processing is not required.

Further, the connecting device for an optical waveguide and an optical fiber according to the present invention has a core center and a central axis of a microcapillary having a core and a clad, wherein the end face of the core is processed to have a convex shape with the core center as an apex. And a plug on which an optical fiber having an outside diameter slightly smaller than the inside diameter of the microcapillary is arranged.

According to the connecting device of the present invention, since the end face of the core of the optical waveguide is processed so as to protrude from the end face of the clad, the adhesion between the end face of the core and the optical fiber in the microcapillary of the plug is improved. Is easily secured.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 4 is a view for explaining the first embodiment of the present invention. FIG. 4 (a) is a perspective view before connection, and FIG.
(B) is a plan view after connection. Projection 13 of optical waveguide 10
Is processed into a desired shape by, for example, RIE (reactive ion etching). In FIG. 4, the protrusion 13 is a core.
It is processed into a semi-cylindrical shape with 11 as the center. As described above, the optical fiber 14 is pressed against the protruding portion 13 of the core 11 that has been processed into a shape protruding from the end face of the clad 12 to perform connection.

Further, by polishing the rotating optical waveguide on the polishing paper, the upper and lower portions of the projection 13 of the optical waveguide 10 can be chamfered, and the end surface of the projection 13 can be processed into a spherical shape. . With this configuration, the mutual contact between the core end faces of the optical waveguide and the optical fiber is more preferably ensured.

The shape of the projection 13 of the optical waveguide 10 can be various shapes as shown in FIG. FIG.
5A is a rectangular cross section, FIG. 5B is a triangular prism with a tapered cross section, and FIG. 5C is a smooth curved cross section of the end face. . In order to reduce the pressing force from the optical fiber, some tapered shape is desirable. FIG. 6 is a perspective view showing a state in which an optical fiber 14 is connected to the optical waveguide end face 13 protruded into a triangular prism shape shown in FIG. 5B. In this way, according to the present invention, by forming the core end face of the optical waveguide into a protruding shape, a small loss, small size, light weight, excellent workability, and reliability can be achieved between the optical fiber and the optical waveguide. High connection is possible.

FIG. 7 is a diagram for explaining an embodiment of the connection device according to the second embodiment of the present invention. The optical waveguide 10 whose end surface is processed into a semi-cylindrical shape is fixed to a substrate 16 having a V-groove 17. At this time, the core 11 of the optical waveguide is aligned so as to be parallel to and directly above the V-groove 17. The microcapillaries 15 are aligned and fixed on the V-groove substrate 16 by V-grooves 17. Further, the distance from the surface of the substrate 16 to the center of the microcapillary is designed to be equal to the distance from the surface of the substrate 16 to the center of the optical waveguide core 11.

That is, the center of the core 11 of the optical waveguide and the center of the microcapillary 15 are on the same line. The inner diameter of the microcapillary 15 is made slightly larger than the outer diameter of the optical fiber 14, and the optical fiber 14 can be smoothly inserted therein. Microcapillary 15
The opening on the side where the optical fiber 14 is inserted is formed with a taper so that the optical fiber 14 can be easily inserted. If the outer peripheral portion of the end face of the optical fiber 14 is chamfered, insertion into the microcapillary 15 is further facilitated.

Optical waveguide 10 and microcapillary 15
Are aligned and fixed to the substrate 16 with an adhesive or the like. When the optical fiber 14 aligned and fixed to the fixed component 18 is inserted into the aligned microcapillary 15 and pressed against the end face of the optical waveguide 10, the center of the core of the optical fiber 14 and the center of the core 11 of the optical waveguide 10 are positioned. Optical fiber
14 and the optical waveguide 10 can be connected. At this time, the optical waveguide
Since the end face of 10 is processed into a shape protruding from the clad end face, the contact between the optical fiber and the optical waveguide is good, and when a slight pressure is applied to the optical fiber, the end face of the optical waveguide is slightly deformed, and the PC is deformed. The connection is realized. For this pressing, a force due to the buckling of the optical fiber as described in FIG. 1 can be used. In this manner, according to the present invention, by forming the core end face of the optical waveguide to protrude from the clad end face, the loss is small, the light weight is excellent in workability, and the optical waveguide and the optical fiber have high reliability. Is obtained.

[0017]

As described above, according to the present invention,
When connecting the optical fiber having the core and the cladding to the optical fiber, by processing the end face perpendicular to the light propagation direction of the optical waveguide into a convex shape with the central portion of the core as a vertex, the end face of the optical fiber and the optical waveguide has a small area. Therefore, the two are easily brought into close contact with each other, and the optical waveguide is slightly deformed by the pressing of the optical fiber, thereby performing the PC connection. As a result, a connection between the optical waveguide and the optical fiber with small connection loss, small size, light weight, excellent workability, and high reliability can be obtained.

Further, a substrate in which the optical waveguide and the microcapillary are aligned and fixed at a position where the core center of the optical waveguide whose end face is formed into a convex shape with the core center as the vertex coincides with the central axis of the microcapillary; According to the connection device of the present invention, comprising a plug in which an optical fiber having an outer diameter slightly smaller than the inner diameter of the microcapillary is arranged, a good connection between the optical waveguide and the optical fiber can be obtained simply by inserting the optical fiber into the microcapillary. A connection can be obtained, and therefore, a connection device between an optical waveguide and an optical fiber having small loss, small size, light weight, excellent workability, and high reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a PC connection between an optical waveguide and an optical fiber.

FIG. 2 is a diagram illustrating an example in which an end face of an optical waveguide is processed into a substantially cylindrical shape in core units.

FIG. 3 is a diagram showing an example of a PC connection between an optical waveguide having a soft flat end face and an optical fiber.

FIG. 4 is a diagram illustrating a connection example according to the present invention.

FIG. 5 is a diagram illustrating an example of a shape of a protruding portion on an end face of an optical waveguide core.

FIG. 6 is a perspective view showing a state in which an optical fiber is connected to an end face of an optical waveguide protruded into a triangular prism shape.

FIG. 7 is a diagram for explaining an embodiment of the optical waveguide and optical fiber connecting device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silica-based optical waveguide 2 Si substrate 3 Glass block for connection reinforcement 4 Precision glass sleeve 5 Optical fiber 6 Fixing member 7 Flexible optical waveguide 8 End of optical waveguide 9 Core of optical waveguide 10 Optical waveguide 11 Core 12 Cladding 13 Projection 14 Optical fiber 15 Microcapillary 16 Substrate 17 V-groove 18 Fixed part

Claims (2)

[Claims] 1. A method for connecting an optical fiber having an optical waveguide having a core and a clad to an optical fiber, wherein an end surface of the optical waveguide perpendicular to the light propagation direction is processed into a convex shape with a central portion of the core as a vertex, and the end surface of the optical fiber is A method for connecting an optical waveguide and an optical fiber, wherein the optical waveguide is connected by being pressed against a convex portion. 2. The optical waveguide and the microcapillary are aligned at a position where the core axis of the optical waveguide, which has a core and a clad and whose end face is processed into a convex shape with the core center as the apex, coincides with the central axis of the microcapillary. An apparatus for connecting an optical waveguide and an optical fiber, comprising: a fixed substrate; and a plug on which an optical fiber having an outer diameter slightly smaller than the inner diameter of the microcapillary is arranged.