JP2007183469A - Optical waveguide for optical path conversion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical-path-conversion optical waveguide that can form a reflection area in an optical waveguide by simple machining. <P>SOLUTION: An optical incident/exit hole 14 of a conical or a semispherical shape is formed from the surface of the optical waveguide 10 into the core 12 by means of a machining drill 15, with a reflection film 16 formed on one side of the optical incident/exit hole 14, and also with resin 17 filled therein. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical waveguide for optical path conversion capable of converting an optical path of an optical signal propagating in a core, such as a polymer optical waveguide.

  In an optical transmission / reception module in which an optical transmission / reception element such as an LD or PD and an optical waveguide are combined, an oblique 45 ° reflection surface is formed on the core of the optical waveguide, and an optical signal propagating in the core is transmitted through a 90 ° optical path Is transmitted to the receiving element or the optical signal from the transmitting element into the core via the reflection surface, so that the signal can be propagated between the optical transmitting and receiving elements.

  In order to form a reflection surface on the core of the optical waveguide, a blade having an inclination angle at the cutting edge, such as a dicing saw, is used, and the reflection surface is formed on the core by cutting the surface of the optical waveguide into a V-shaped cross section (Patent Literature). 1) When manufacturing an optical waveguide, a 45 ° reflection surface is previously formed on the core (Patent Documents 2 and 3).

Japanese Patent Laid-Open No. 10-300961 JP 2002-107561 A JP 2004-78084 A

  However, when cutting the V-shaped cross section in the optical waveguide using a dicing saw or the like as in Patent Document 1, the cutting is performed with the dicing saw so as to cross the optical waveguide. There is a problem of cutting. Further, in Patent Documents 2 and 3, since the reflection surface is formed at the time of manufacturing the optical waveguide, there is a problem that the reflection surface cannot be formed later on a normal optical waveguide.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an optical path conversion optical waveguide that can solve the above-described problems and can form a reflection surface on the optical waveguide by simple processing.

  In order to achieve the above object, an invention according to claim 1 is an optical waveguide comprising a substrate, a core formed on the substrate for transmitting an optical signal, and a clad covering the core and the substrate. Through the core to form a conical or hemispherical light entrance / exit hole, a reflective film is formed on one side of the light entrance / exit hole, and the light entrance / exit hole is formed on the optical waveguide. An optical waveguide for optical path conversion, characterized in that it is formed with an angle of 45 ° with respect to the surface and a conical hole and the core faces the conical surface.

  According to a second aspect of the present invention, after a reflection film is formed in the light incident / exit hole, the light incident / exit hole is filled with a resin having a refractive index equivalent to that of the core. It is.

  A third aspect of the present invention is the optical path converting optical waveguide according to the first or second aspect, wherein the light incident / exit hole is formed by cutting a tip with a conical or semi-circular processing drill.

  According to a fourth aspect of the present invention, a positioning small hole is formed by laser processing or the like in an optical waveguide in which a light incident / exit hole is to be formed, and the positioning small hole is cut with a machining drill to form a light incident / exit hole. An optical waveguide for changing an optical path according to claim 3.

  According to the present invention, the light incident / exit hole can be easily processed only at a desired position by cutting the surface of the optical waveguide with a machining drill or the like, and the core surface facing the light incident / exit hole is a curved surface. Therefore, an excellent effect of improving the coupling efficiency due to the lens effect is exhibited.

  A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

  1 and 2 show an embodiment of the present invention.

  In the optical waveguide 10, a core 12 having a rectangular cross section serving as an optical transmission path is formed on an underclad 11 made of epoxy resin, acrylic resin, polyimide resin, or the like, and an overclad 13 is formed on the underclad 11 so as to cover the core 12. Formed.

  For example, a conical light incident / exit hole 14 is formed on the surface of the optical waveguide 10 over the core 12.

  The light incident / exit hole 14 is formed by cutting the surface of the optical waveguide 10 with a machining drill 15 having a conical tip 15 s, and the core 12 is formed on the conical surface of the light incident / exit hole 14. Is formed to such a depth as to face (FIG. 1A).

  A reflective film 15 having a film thickness of 100 nm or more formed of a vapor deposition surface of gold or aluminum is formed on one side of the light incident / exit hole 14, that is, the surface facing the core surface 12s on the incident / exit side (FIG. 1B). )), And then filled with a resin 16 having a refractive index equivalent to that of the core 12 (FIG. 1C).

  As shown in FIG. 2, the light entrance / exit holes 14 are formed for each core 12 when many cores 12 are aligned.

  In this case, if the light entrance / exit hole 14 is a cone, it is formed with a 45 ° angle and a conical hole with respect to the surface of the optical waveguide. In order to make the core 12 face the conical surface. The diameter of the light entrance / exit hole 14 needs to be 1.5 times or more the width of the core 12 (usually 30 to 100 μm), but it is adjacent when the interval between the aligned cores 12 is narrow. The light entrance / exit holes 14 are formed so as to wrap to some extent within a range where there is no hindrance.

  In the above, the optical waveguide 10 on the light entrance / exit hole 14 is mounted with a transmitting / receiving element (not shown) such as a surface light emitting element or a light receiving element, and for example, an optical signal propagated in the core 12 is used for light entrance / exit The light is emitted to the hole 14, reflected by the reflective film 16, and the optical path is converted upward as shown by the arrow in the figure. In this case, since the reflection surface 12s is formed in a shape along the conical surface of the light incident / exit hole 14, it is condensed when reflected by the reflection film 16, so that the coupling efficiency can be improved.

  FIG. 3 shows another embodiment of the present invention.

  In the embodiment of FIG. 1 and FIG. 2, the example in which the light incident / exit hole 14 is formed by cutting the front end 15 s of the processing drill 15 directly on the surface of the optical waveguide 10 has been described. Is about 50 to 500 μm, which is thicker than the core diameter. Therefore, in order to cut the light incident / exit hole 14 more accurately, positioning with a laser beam LB as shown in FIG. By forming the small hole 20 and cutting the contact small hole 20 by applying the tip 15s of the machining drill 15 to the positioning small hole 20, as shown in FIG. 3B, the light incident / exit hole 14 can be accurately formed. it can. The positioning small holes 20 may be formed so as to penetrate the polymer substrate 11 as illustrated, or may be formed to a depth that reaches the polymer substrate 11.

  After forming the light incident / exit hole 14, as described in FIG. 1, the reflective film 16 is formed by vapor deposition of gold or aluminum, and then the light incident / exit hole 14 is filled with the resin 17.

  FIG. 4 shows still another embodiment of the present invention.

  In the embodiment described above, an example in which the light incident / exit hole 14 is formed in a conical shape has been shown, but in the present embodiment, an example in which the light incident / exit hole 14a is a semi-spherical shape is shown. Further, depending on the shape of the drill, it can be formed in a shape with high optical path conversion efficiency and coupling efficiency, such as a semi-oval shape and a semi-elliptical cross section.

  Thus, by forming the light entrance / exit hole 14a in a semi-spherical shape or a semi-oval shape instead of a conical shape, the light condensing property can be further improved.

It is a figure which shows one embodiment of this invention. FIG. 2 is an overall perspective view of FIG. It is a figure which shows other embodiment of this invention. It is a figure which shows other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical waveguide 12 Core 14 Light incident / exit hole 15 Processing drill 16 Reflective film 17 Resin

Claims (4)

  An optical waveguide comprising a substrate, a core formed on the substrate for transmitting an optical signal, and a clad covering the core and the substrate, and having a conical or hemispherical shape penetrating the core from the surface of the optical waveguide. A light entrance / exit hole is formed, a reflective film is formed on one side of the light entrance / exit hole, and the light entrance / exit hole has a 45 ° angle and a conical hole with respect to the surface of the optical waveguide. An optical waveguide for optical path conversion, characterized in that the optical waveguide is formed so that the core faces the conical surface.   The optical waveguide for changing an optical path according to claim 1, wherein after the reflective film is formed in the light incident / exit hole, the light incident / exit hole is filled with a resin having a refractive index equivalent to that of the core.   The optical path converting optical waveguide according to claim 1 or 2, wherein the light entrance / exit hole is formed by cutting a tip with a conical or semi-circular processing drill. 4. The optical path conversion according to claim 3, wherein a positioning small hole is formed by laser processing or the like in an optical waveguide in which a light incident / exit hole is to be formed, and the positioning small hole is cut by a machining drill to form a light incident / exit hole. Optical waveguide.

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