JPH0573607U - Optical waveguide and optical fiber connection structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a connection structure for an optical waveguide and an optical fiber, which facilitates alignment work when connecting the optical waveguide and the optical fiber. [Structure] A connection structure of an optical waveguide and an optical fiber, in which the optical waveguide 4 provided on an optical waveguide substrate 5 and a core of the optical fiber are brought close to each other by a predetermined distance and the two are distributed and coupled. A connector 7 having a linear V groove 61 for a coupling portion on its surface is prepared. On the other hand, the optical fiber is provided with a coupling portion 3 in which the clad is removed and the thickness of the clad is concentrically thinned. Further, the optical waveguide substrate 5 is provided with a convex portion 11 in which the optical waveguide substrate 5 including the optical waveguide 4 and having a predetermined width is formed at a predetermined height. The coupling portion 3 of the optical fiber is inserted into the coupling portion V groove 61, and the convex portion 1 of the optical waveguide substrate 5 is inserted into the coupling portion V groove 61.
1 is inserted so that the optical waveguide substrate 5 is covered on the connector 7 and the optical fiber coupling portion 3 is connected to the coupling portion V of the connector 7.
It is sandwiched between the groove 61 and the convex portion 11 of the optical waveguide substrate 5.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a connection structure between an optical waveguide and an optical fiber.

[0002]

[Prior art]

 In order to couple the optical waveguide and the optical fiber by distributed coupling, usually, a part or the whole circumference of the optical fiber cladding is thinned by polishing (cutting or etching etc.) a predetermined distance, and the thinned portion is thinned. The optical waveguide and the core of the optical fiber were brought into contact with each other and fixed to each other by a predetermined distance, whereby the both were coupled. In addition, it is desirable that the length of this coupling portion is set to a length necessary for the most efficient transmission of light.

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 71 having a rectangular parallelepiped shape and provided with three V grooves 73 parallel to the upper surface thereof is prepared. The spacing between the V-grooves 73 is the same as the spacing between the optical waveguides 61 described below. Then, the optical fiber 75 is inserted and fixed in each V groove 73 of the connector 71. Then, the clad portion exposed from the V groove 73 of the optical fiber 75 is polished to eliminate a step with respect to the surface a of the connector 71.

Then, as shown in FIG. 2B, the polishing surface a of the connector 71 is brought into close contact with the optical waveguide substrate 60 to bring the optical waveguides 61 and the cores of the optical fibers 75 close to each other, so that the coupling efficiency between them is improved. Adjust (align) the maximum position, and then bond the two.

[0005]

[Problems to be solved by the device]

 However, when the optical waveguide and the optical fiber are connected by the above method, the positioning adjustment between them is performed in the axial direction of the optical fiber 75 and in the radial direction of the optical fiber 75, which is parallel to the polishing surface a of the connector 71. However, there is a problem that the adjustment work is complicated and takes time.

The present invention has been made in view of the above points, and an object of the present invention is to perform an aligning operation when connecting an optical waveguide and an optical fiber and to reliably connect the optical waveguide and the optical fiber. It is to provide a fiber connection structure.

[0007]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides an optical waveguide-optical fiber connection structure in which the optical waveguide 4 provided on the optical waveguide substrate 5 and the core 2 of the optical fiber 10 are brought close to each other by a predetermined distance and the two are distributedly coupled. The optical fiber 10 is provided with a connector 7 having a straight V-shaped groove (a V-shaped groove 61 for a coupling portion) on the top thereof, and the cladding 1 of the optical fiber 10 is removed concentrically so that the thickness of the cladding 1 is concentric. Is provided with a connecting portion 3 which is thinned or lost, and the optical waveguide substrate 5 is provided with a convex portion 11 in which an optical waveguide substrate 5 having a predetermined width including the optical waveguide 4 is formed at a predetermined height. So that the coupling portion 3 of the optical fiber 10 is inserted into the V groove (V groove 61 for coupling portion) of the optical fiber 10 and the convex portion 11 of the optical waveguide substrate 5 is inserted into the V groove (V groove 61 for coupling portion). Cover the connector 7 with the optical waveguide substrate 5 It was allowed clamped by the V-groove (coupling portion for V groove 61) and the convex portion 11 of the optical waveguide substrate 5 of the coupling part 3 the connector 7 of the optical fiber 10.

[0008]

[Action]

 The coupling portion 3 of the optical fiber 10 is reliably positioned and stored in the bottom of the V groove (the coupling portion V groove 61), and by covering the connector 7 with the optical waveguide substrate 5, the coupling portion 3 is formed. Is sandwiched between the convex portion 11 of the optical waveguide substrate 5 and the V groove (V groove 61 for coupling portion). Therefore, the alignment work of the optical fiber 10 and the optical waveguide 4 can be easily performed.

[0009]

【Example】

 Hereinafter, an embodiment of the present invention will be described in detail with reference to 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. As shown in the figure, in this embodiment, the coupling portion 3 of the optical fiber is inserted into the V groove 6 (V groove 61 for coupling portion) of the connector 7 and the optical waveguide substrate 5 is placed on the connector 7 to cover it. The coupling portion 3 is sandwiched between the V groove 6 of the connector 7 (the coupling portion V groove 61) and the convex portion 11 provided on the optical waveguide substrate 5, whereby the coupling portion 3 and the optical waveguide 4 are connected. Each component will be described below.

2A and 2B are views 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 figure, at the end of the optical fiber 10, there is provided a coupling portion 3 in which the cladding 1 is thinly concentrically formed. The length L ₁ of the coupling portion 3 is set to a coupling length L required for the most efficient transmission of light by distributed coupling when the coupling portion 3 is brought close to the optical waveguide 4 described below.

The coupling portion 3 is formed by etching (for example, immersing in the concentrated hydrofluoric acid or the like) the end portion of the optical fiber 10. Since the clad 1 of the optical fiber 10 is concentric, by controlling the time for immersing the optical fiber 10 in the etching solution, it is possible to obtain the joint portion 3 having a uniform clad thickness over the entire circumference. If it is manufactured by using the etching means as described above, a large number of the coupling portions 3 of the optical fibers 10 can be manufactured at one time, which is preferable. The root portion A of the coupling portion 3 of the optical fiber 10 manufactured in this manner is fragile in strength and easily broken, so it is preferable to apply a resin or the like to reinforce it.

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-grooves 6 on the surface of a plate formed in a substantially rectangular parallelepiped shape. The V-groove 6 has two stages of a V-groove 61 for the coupling portion into which the coupling portion 3 of the optical fiber 10 is inserted and a V-groove 63 for the optical fiber into which the unetched portion of the optical fiber 10 is inserted. The spacing between the respective V-grooves 6 is the same as the spacing between the optical waveguides 4 described below. The length L ₂ of the V groove 61 for the coupling portion is the same as the length L ₁ of the coupling portion 3 of the optical fiber 10.

Next, FIG. 4 is a perspective view showing an optical waveguide substrate 5 used in this embodiment. As shown in the figure, the optical waveguide substrate 5 is formed in a rectangular parallelepiped shape, and three convex portions 11 are formed on the upper surface by the linear optical waveguide 4 and the optical waveguide substrates 5 having a predetermined width on both sides thereof. Is made. The convex portion 11 is formed by removing the surface B of the optical waveguide substrate 5 other than the convex portion 11 by etching or polishing. The length L ₃ of the convex portion 11 is longer than the length L ₁ of the coupling portion 3 of the optical fiber 10 (that is, L ₃ > L ₁ = L ₂ = L in this embodiment). ).

To connect the optical waveguide 4 and the optical fiber 10, the optical fiber 10 is first inserted into the V groove 6 as shown in FIG. At this time, the coupling portion 3 of the optical fiber 10 is inserted into the coupling portion 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 the optical waveguide substrate 5 is covered and bonded / fixed on the connector 7 shown in FIG. It should be inserted in the V groove 61.

The state at this time is shown in FIG. 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 set to a height required for the coupling portion 3 of the optical fiber 10 to be sandwiched between the convex portion 11 and the coupling portion V groove 61 from above and below.

On the other hand, as shown in the same figure, the width of this convex portion 11 is set to a width required for both corner portions to abut on the inner surface of the V groove 61 for the coupling portion. By doing this, the positioning of the optical waveguide substrate 5 when the convex portion 11 is inserted into the coupling portion V groove 61 becomes reliable, and the optical waveguide substrate 5 can be positioned by simply inserting the convex portion 11 into the coupling portion V groove 61. The central portion of the waveguide 4 is surely brought into close contact with the outer peripheral surface of the coupling portion 3 of the optical fiber 10, and a good 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 is transmitted most efficiently without any special alignment work (because of the length L of the coupling portion 3). ₁ is L).

It should be noted that the void C in the V groove 61 for the coupling portion may be filled with matching oil.

Although one 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 was left thin on the surface of the coupling part of the optical fiber, but the clad may be completely removed. In this case, a layer (eg, 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-described embodiment, the length of the coupling portion of the optical fiber and the length of the coupling portion V groove of the connector into which the coupling portion is inserted are set to the length L at which light is most efficiently transmitted. However, these lengths may be L or more. In this case, the relative positional relationship between the respective 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 becomes L.

[0021]

[Effect of the device]

 As described in detail above, the optical waveguide and optical fiber connection structure according to the present invention has the following excellent effects. The alignment work of the optical fiber and the optical waveguide becomes easy or unnecessary.

Since the coupling portion of the optical fiber is formed concentrically by removing the clad, it is not necessary to polish the clad as in the conventional example shown in FIG. 5, and a large amount can be manufactured at once by etching.

Since the film thickness of the clad at the coupling portion of the optical fiber is constant, no matter how the coupling portion is inserted and fixed in the V groove, the coupling efficiency does not change.

[Brief description of 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 portion of an optical fiber 10 used in this embodiment.

FIG. 3 shows an optical fiber 10 as a connector 7 used in this 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 this embodiment.

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

[Explanation of symbols]

 10 Optical Fiber 1 Clad 2 Core 3 Coupling Section 4 Optical Waveguide 5 Optical Waveguide Substrate 11 Convex Section 6 V-Groove 61 V-Groove for Coupling 63 V-Groove for Optical Fiber 7 Connector

Claims (1)

[Scope of utility model registration request] 1. A connection structure between an optical waveguide and an optical fiber, wherein the optical waveguide provided on an optical waveguide substrate and the core of the optical fiber are brought close to each other by a predetermined distance and distributedly coupled to each other, a linear V groove is provided on the surface. The optical fiber includes a connector, and the optical fiber is provided with a coupling portion in which the clad is removed concentrically so that the thickness of the clad is concentrically thinned or eliminated, and the optical waveguide substrate includes a predetermined optical waveguide. An optical waveguide substrate having a width is formed at a predetermined height so that a convex portion of the optical waveguide substrate can be inserted into the V groove while inserting the coupling portion of the optical fiber into the V groove of the connector. A connection structure of an optical waveguide and an optical fiber, characterized in that an optical waveguide substrate is covered on a connector so that a coupling portion of the optical fiber is sandwiched between a V groove of the connector and a convex portion of the optical waveguide substrate.