JP2590123Y2 - 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 FIGS. 5, 6 and 7 are perspective views showing a conventional connection method between an optical waveguide and an optical fiber.

That is, in the conventional example shown in FIG. 5, an optical fiber 55 is bonded to an end face of an optical waveguide 53 provided on an optical waveguide substrate 51 to adjust the optical axes of the two, and thereafter, the adhesive 57 is used. Is fixed.

[0006] In the conventional example shown in FIG.
9, an optical fiber 65 is placed in a groove 63 provided in a guide block 61, and an end face of the optical fiber 65 is joined to an end face of an optical waveguide 67 to adjust both optical axes. Is fixed in the groove 63 with an adhesive 69.

In the conventional example shown in FIG. 7, a guide groove 75 is provided at an end of an optical waveguide 73 in an optical waveguide substrate 71, and a concave portion 77 is provided in the guide groove 75. The fiber 79 is inserted and its end face is bonded to the end face of the optical waveguide 73, and the concave portion 77 is filled with an adhesive (not shown) to fix the optical fiber 79 to the optical waveguide substrate 71.

[0006]

However, in each of the above-mentioned conventional examples, the optical fibers 55, 65, and 79 are bonded at the time of bonding.
Are the optical waveguide substrate 51, the guide block 61 and the guide groove 7.
5, the adhesive strength of the adhesive becomes weak due to the change with time and the external environment (particularly, temperature and vibration). In the worst case, the optical fibers 55, 65, and 79 are attached to the optical waveguide substrate. There was a problem that it deviated from 51 etc. This is fatal for an optical device.

[0007] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a light guide even when the adhesive strength of an adhesive connecting an optical waveguide and an optical fiber is reduced due to a change over time or an external environment. An object of the present invention is to provide a connection structure between an optical waveguide and an optical fiber that can reliably maintain a connection state between a waveguide and an optical fiber.

[0008]

In order to solve the above-mentioned problems, the present invention is directed to an optical waveguide in which an end of an optical fiber 1 is joined and fixed to an end of an optical waveguide 3 provided on an upper surface side of an optical waveguide substrate 4. In the connection structure between a waveguide and an optical fiber, a groove-shaped optical fiber insertion portion 6 for inserting the optical fiber 1 is provided at an end of the optical waveguide 3 of the optical waveguide substrate 4 itself.
To provided, smaller than the bottom portion of the area S2 of the area S1 of the surface portion when viewed through the optical fiber insertion portion 6 from the upper surface side of the optical waveguide substrate 4, and the optical fiber 1 the optical fiber insertion part 6 The width on the end face side of the optical waveguide substrate 4 when viewed from the insertion side is set to be smaller than the maximum width in the optical fiber insertion portion 6.

[0009]

The optical fiber insertion portion is filled with the adhesive and the optical fiber is fixed, so that the optical fiber insertion portion can be applied to the front surface of the optical waveguide substrate even when a force for pulling the optical fiber in the front direction is applied. Since the width is smaller than the maximum width of the hardened portion of the adhesive 5 in the optical fiber insertion portion 6, it does not come off. Even if a force for lifting the optical fiber 1 upward is applied, the area S ₁ is smaller than the area S _{2 and} does not come off.

[0010]

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 perspective view showing a first embodiment of the present invention. As shown in the drawing, in this embodiment, a groove-shaped optical fiber insertion portion 6 is formed at an end of an optical waveguide 3 provided on an optical waveguide substrate 4, and an end of the optical fiber 1 is provided in the optical fiber insertion portion 6. The end portion of the core 2 is joined to the end surface of the optical waveguide 3 by inserting a portion, and then the optical fiber insertion portion 6 is filled with an adhesive 5 and cured.

FIG. 2 is a diagram showing a state when the optical fiber insertion section 6 is viewed from the upper surface side, and FIG. 2A shows a state when the optical fiber 1 is inserted into the optical fiber insertion section 6. FIG. 3B is a diagram showing an area S ₁ of a surface portion of the optical fiber insertion portion 6, and FIG. 3C is a diagram showing an area S ₂ of a bottom portion of the optical fiber insertion portion 6. is there. On the other hand, FIG. 3 is a diagram showing a state when the optical fiber insertion section 6 is viewed from the side where the optical fiber 1 is inserted.

As shown in both figures, this optical fiber insertion portion 6
Are formed such that the area S ₁ of the surface portion when viewed from the top surface side is smaller than the area S _{2 of the} bottom surface portion. When the optical fiber insertion section 6 is viewed from the side where the optical fiber 1 is inserted, the width at the end face 8 of the optical waveguide substrate 4 is:
It is formed smaller than the maximum width in the optical fiber insertion section 6. Therefore, the width b shown in FIG. 2A is formed larger than the width a.

The optical fiber insertion section 6 is formed by photolithography, but may be formed by another method.

Then, the end of the optical fiber 1 is inserted into the optical fiber insertion section 6, the end face of the core 2 is joined to the end face of the optical waveguide 3, and the optical axis between the two is adjusted. The adhesive 5 is filled in the fiber insertion section 6 and cured. Before the optical axis adjustment of the core 2 and the optical waveguide 3 of the optical fiber 1 is performed, the adhesive 5 is filled in the optical fiber insertion portion 6, and after the optical axis adjustment is performed, the adhesive 5 is cured. Good. Further, low melting point glass or solder may be used instead of the adhesive 5.

If the optical waveguide substrate 4 and the optical fiber 1 are connected and fixed as described above, even if the adhesive force of the adhesive 5 is reduced due to aging or an external environment, the adhesive 5
The optical fiber 1 does not shift in any of the front-back direction (optical axis direction), the up-down direction, and the left-right direction due to the shape of the optical fiber insertion section 6. That is, even if a force for pulling the optical fiber 1 in the forward direction is applied, the width a is smaller than the width b, and thus the optical fiber 1 does not come off. Also, even if a force for pulling the optical fiber 1 upward is applied, the area S ₁ is smaller than the area S _{2 and} does not come off.

FIG. 4 is a view showing a state in which the optical fiber 11 is inserted into the optical fiber insertion section 16 according to the second embodiment of the present invention. FIG. 4A is a plan view thereof, and FIG. )
FIG. 3 is a view of the optical fiber insertion section 16 as seen from the side where the optical fiber 11 is inserted.

As shown in FIG. 1, the optical fiber insertion section 16 according to this embodiment also
The area S ₃ of the surface portion when viewed from the upper surface side is formed to be smaller than the area S ₄ of the bottom portion. The width c at the end face 18 of the optical waveguide substrate 14 when the optical fiber insertion section 16 is viewed from the side where the optical fiber 11 is inserted is formed to be smaller than the maximum width d in the optical fiber insertion section 16. ing.

Even with such a configuration, the optical fiber 11
There is no displacement in any of the front-back, left-right, and up-down directions, and the fixing is secure.

[0019]

As described above in detail, according to the connection structure between the optical waveguide and the optical fiber according to the present invention, the adhesive force of the adhesive used for connecting the optical waveguide and the optical fiber changes with time. It has an excellent effect that the connection state between the optical waveguide and the optical fiber can be reliably maintained even if it becomes weak due to the influence of the external environment.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a view showing a state when the optical fiber insertion section 6 is viewed from the upper surface side, and FIG. 2A is a view showing a state when the optical fiber 1 is inserted into the optical fiber insertion section 6; FIG. 2B shows the area S ₁ of the surface of the optical fiber insertion section 6, and FIG. 2C shows the area S ₁ of the bottom of the optical fiber insertion section 6.
It is a diagram illustrating a _2.

FIG. 3 is a diagram showing a state when the optical fiber insertion section 6 is viewed from a side where the optical fiber 1 is inserted.

FIG. 4 is a diagram showing a state when the optical fiber 11 is inserted into the optical fiber insertion section 16 according to the second embodiment of the present invention.

FIG. 5 is a perspective view showing a conventional connection method between an optical waveguide and an optical fiber.

FIG. 6 is a perspective view showing a conventional method for connecting an optical waveguide and an optical fiber.

FIG. 7 is a perspective view showing a conventional method for connecting an optical waveguide and an optical fiber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1,11 Optical fiber 2,12 Optical fiber core 3,13 Optical waveguide 4,14 Optical waveguide board 5 Adhesive 6,16 Optical fiber insertion part 8,18 End face of optical waveguide board

Claims (1)

(57) [Scope of request for utility model registration] 1. A connection structure between an optical waveguide and an optical fiber, wherein an end of an optical fiber is joined to and fixed to an end of the optical waveguide provided on an upper surface side of the optical waveguide substrate. At the end, a groove-shaped optical fiber insertion part for inserting the optical fiber is provided on the optical waveguide base.
The optical fiber insertion portion is provided on the plate itself, the surface area of the optical fiber insertion portion when viewed from the top surface side of the optical waveguide substrate is smaller than the area of the bottom portion, and the optical fiber insertion portion is formed of an optical fiber. connection structure of the optical waveguide and the optical fiber, characterized in that it has less than the maximum width of the optical fiber insertion portion the width of the optical waveguide substrate end surface side as viewed from the side of inserting the.