JP2575742Y2 - Connection structure between optical waveguide and optical fiber - Google Patents

Description

[Detailed description of the invention]

[0001]

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

[0002]

2. Description of the Related Art To couple an optical waveguide and an optical fiber by distributed coupling, a part or the entire circumference of the cladding of the optical fiber is usually thinned by polishing (may be cut or etched) for a predetermined distance. The portion was fixed on the optical waveguide by contacting the core with the optical waveguide and the core of the optical fiber by a predetermined distance. It is desirable that the length of the coupling portion be a length necessary for transmitting light most efficiently.

FIG. 5 is a perspective view showing a conventional method for connecting an optical waveguide and an optical fiber. As shown in FIG. 1A, in this conventional example, first, a connector 7 having a rectangular parallelepiped shape and provided with three V grooves 73 parallel to the upper surface thereof is provided.
Prepare 1 The interval between the V grooves 73 is the same as the interval between the optical waveguides 61 described below. Then, an optical fiber 75 is inserted into each V-groove 73 of the connector 71 and fixed. Then, the clad portion of the optical fiber 75 exposed from the V groove 73 is polished to eliminate a step with the surface a of the connector 71.

Then, as shown in FIG. 1B, the polished surface a of the connector 71 is brought into close contact with the optical waveguide substrate 60 so that each optical waveguide 61 and the core of the optical fiber 75 are brought close to each other.
The position where the coupling efficiency between the two is maximized is determined by adjusting (aligning), and then the two are bonded.

[0005]

However, when the optical waveguide and the optical fiber are connected by the above method, the positioning between them is adjusted by the axial direction of the optical fiber 75 and the optical fiber 7.
5 has to be performed in two directions, that is, the direction parallel to the polished surface a of the connector 71, and the adjustment work is complicated and time-consuming.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide an optical waveguide and an optical fiber which can easily perform alignment work when connecting the optical waveguide and the optical fiber and can surely connect the two. To provide a connection structure.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an optical waveguide for distributively coupling an optical waveguide 4 provided on an optical waveguide substrate 5 and a core 2 of an optical fiber 10 by bringing them close to each other by a predetermined distance. In the connection structure between the optical fiber and the optical fiber, a connector 7 having a linear V-groove (V-groove 61 for a coupling portion) on the surface is provided, and the cladding 1 of the optical fiber 10 is concentrically removed. A coupling portion 3 in which the thickness of the clad 1 is concentrically reduced or eliminated is provided,
The optical waveguide substrate 5 is provided with a convex portion 11 in which the optical waveguide substrate 5 having a predetermined width including the optical waveguide 4 is formed at a predetermined height, and an optical fiber is provided in a V-groove (V-groove 61 for a coupling portion) of the connector 7. 10 and the V-groove (V
The optical waveguide substrate 5 is put on the connector 7 so that the projection 11 of the optical waveguide substrate 5 is inserted into the groove 61), and the coupling portion 3 of the optical fiber 10 is connected to the V-groove (V-groove 6 for coupling portion) of the connector 7.
1) and the convex portion 11 of the optical waveguide substrate 5.

[0008]

The coupling section 3 of the optical fiber 10 is securely positioned and housed at the bottom of the V-groove (V-groove 61 for the coupling section). Indicates the convex portion 11 of the optical waveguide substrate 5 and the V groove (V for the coupling portion)
It is clamped by the groove 61). Therefore, the optical fiber 10
And the optical waveguide 4 can be easily aligned.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a front view showing one embodiment of a connection structure between an optical waveguide and an optical fiber according to the present invention. In this embodiment, as shown in FIG.
The coupling portion 3 of the optical fiber is inserted into the (coupling portion V-groove 61), and the optical waveguide substrate 5 is put on the connector 7, and the coupling portion 3 is connected to the V-groove 6 of the connector 7 (coupling portion V-groove 61). And the convex portion 11 provided on the optical waveguide substrate 5,
Thus, the coupling portion 3 and the optical waveguide 4 are connected.
Hereinafter, each component will be described.

FIGS. 2A and 2B are diagrams showing an end portion of the optical fiber 10 used in the present embodiment. FIG. 2A is a left side view, and FIG. 2B is a side sectional view. As shown in the drawing, a coupling portion 3 in which the clad 1 is concentrically thinned is provided at the end of the optical fiber 10. In addition, the length L of the connecting portion 3
Reference numeral ₁ denotes a coupling length L necessary for transmitting light most efficiently in distributed coupling when the coupling portion 3 is brought close to an optical waveguide 4 described below.

The coupling portion 3 is formed by etching the end of the optical fiber 10 (for example, immersing it in concentrated hydrogen fluoride or the like). Since the cladding 1 of the optical fiber 10 is concentric, by controlling the time during which the optical fiber 10 is immersed in the etching solution, it is possible to obtain the coupling portion 3 having a uniform cladding thickness over the entire circumference. It is preferable to manufacture the optical fiber 10 by using the etching means in this manner because a large number of coupling portions 3 of the optical fibers 10 can be manufactured at one time. Note that the root portion A of the coupling portion 3 of the optical fiber 10 manufactured in this manner is fragile in terms of strength and is easily broken, so it is preferable to reinforce by applying a resin or the like.

FIG. 3 is a perspective view showing the connector 7 used in this embodiment. As shown in the figure, the connector 7 is configured by providing three parallel V-shaped grooves 6 on the surface of a plate formed in a substantially rectangular parallelepiped shape. The V-groove 6 is constituted by two steps of a V-groove 61 for a coupling portion for inserting the coupling portion 3 of the optical fiber 10 and a V-groove 63 for an optical fiber for inserting an unetched portion of the optical fiber 10. The distance between the V grooves 6 is the same as the distance between the optical waveguides 4 described below. The length L of the V groove 61 for the coupling portion
₂ is the same as the length L ₁ of the coupling portion 3 of the optical fiber 10.

FIG. 4 is a perspective view showing an optical waveguide substrate 5 used in this embodiment. As shown in the figure, this optical waveguide substrate 5 is formed in a rectangular parallelepiped shape, and a linear optical waveguide 4 and optical waveguide substrates 5 of a predetermined width on both sides thereof are provided on the upper surface thereof.
Thus, three convex portions 11 are formed. This convex part 1
1 is formed by removing the surface B of the optical waveguide substrate 5 other than the projections 11 by etching or polishing. The length L ₃ of the convex portion 11 is the same as that of the optical fiber 1.
0 is formed longer than the length L ₁ of the coupling portion 3 (that is, in this embodiment, L ₃ > L ₁ = L ₂ = L).

The optical waveguide 4 and the optical fiber 1
0, first, as shown in FIG.
0 is inserted into the V groove 6. At this time, the coupling part 3 of the optical fiber 10 is inserted into the coupling part V groove 61 of the connector 7, and the unetched portion of the optical fiber 10 is inserted into the optical fiber V groove 63. Next, the optical waveguide substrate 5 shown in FIG. 4 is turned upside down and put on and adhered and fixed on the connector 7 shown in FIG. 3. At this time, each convex portion 11 of the optical waveguide substrate 5 is connected to each connecting portion V of the connector 7. It is inserted into the groove 61.

FIG. 1 shows the state at this time. As shown in the figure, the coupling portion 3 of the optical fiber 10 is sandwiched between the coupling portion V-groove 61 of the connector 7 and the convex portion 11 of the optical waveguide substrate 5. Here, the height of the convex portion 11 is a height necessary for the coupling portion 3 of the optical fiber 10 to be clamped from above and below by the convex portion 11 and the V groove 61 for the coupling portion.

On the other hand, as shown in the figure, the width of the convex portion 11 is a width necessary for both corners of the convex portion 11 to come into contact with the inner surface of the V groove 61 for the joint portion. By doing so, the optical waveguide substrate 5 when the convex portion 11 is inserted into the V-groove 61 for the coupling portion is formed.
And the convex portion 11 is connected to the V-groove 6 for the connecting portion.
The center portion of the optical waveguide 4 is securely brought into close contact with the outer peripheral surface of the coupling portion 3 of the optical fiber 10 simply by being inserted into the optical fiber 10, and a favorable coupling state can be formed.

The coupling length between the optical waveguide 4 and the optical fiber 10 is the length L at which light can be transmitted most efficiently without performing any special alignment work (because the length L of the coupling portion 3). ₁
Is L).

The gap C in the joint V-groove 61 may be filled with matching oil.

Although the embodiment of the present invention has been described in detail above, the present invention is not limited to this, and the following modifications are possible, for example. In the above embodiment, the clad is left thin on the surface of the coupling portion of the optical fiber, but the clad may be completely removed. In this case, any layer (for example, an adhesive) corresponding to the clad may be interposed between the core of the optical fiber to be coupled and the optical waveguide.

In the above embodiment, the length of the coupling portion of the optical fiber and the V for the coupling portion of the connector into which the coupling portion is inserted.
The lengths of the grooves are set to the lengths L at which light is transmitted most efficiently, but these lengths may be longer than the lengths L. In this case, the relative positional relationship between the members may be adjusted in the optical axis direction so that the coupling length between the coupling portion of the optical fiber and the convex portion of the optical waveguide substrate is L.

[0021]

As described above in detail, according to the connection structure between the optical waveguide and the optical fiber according to the present invention, the following excellent effects are obtained. Alignment work of the optical fiber and the optical waveguide becomes easy or unnecessary.

Since the coupling portion of the optical fiber is formed by removing the clad concentrically, it is not necessary to polish the clad as in the conventional example shown in FIG.

Since the thickness of the cladding at the coupling portion of the optical fiber is constant, the coupling efficiency does not change regardless of how this coupling portion is inserted or fixed in the V-groove.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a connection structure between an optical waveguide and an optical fiber according to the present invention.

FIG. 2 is a diagram showing an end of an optical fiber 10 used in the present embodiment.

FIG. 3 shows an optical fiber 10 connected to a connector 7 used in the present embodiment.
It is a perspective view which shows the state which attaches.

FIG. 4 is a perspective view showing an optical waveguide substrate 5 used in the present embodiment.

FIG. 5 is a perspective view showing a conventional method for connecting an optical waveguide and an optical fiber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Optical fiber 1 Cladding 2 Core 3 Coupling part 4 Optical waveguide 5 Optical waveguide board 11 Convex part 6 V groove 61 V groove for coupling part 63 V groove for optical fiber 7 Connector

Claims (1)

(57) [Scope of request for utility model registration] 1. A connection structure of an optical waveguide and an optical fiber for distributing and coupling the optical waveguide provided on the optical waveguide substrate and the core of the optical fiber by a predetermined distance, wherein a linear V-groove is provided on the surface. In addition to the connector, the optical fiber is provided with a coupling portion in which the clad is removed concentrically to reduce or eliminate the thickness of the clad concentrically, and the optical waveguide substrate includes an optical waveguide. A convex portion having a width of an optical waveguide substrate formed at a predetermined height is provided, and a coupling portion of an optical fiber is inserted into a V-groove of the connector and the convex portion of the optical waveguide substrate is inserted into the V-groove. A connection structure between an optical waveguide and an optical fiber, wherein the optical waveguide substrate is put on the connector, and the coupling portion of the optical fiber is held between the V groove of the connector and the projection of the optical waveguide substrate.