JPH04333004A - Light guide device - Google Patents

Abstract

PURPOSE:To guide light, propagated in a light guide, out at right angles to a substrate without any loss and to eliminate the need for accuracy which is high enough to form a diffraction grating on the light guide. CONSTITUTION:The light guide device is equipped with the substrate made of a material transmitting light and the light guide 2 which is formed on the substrate 1 by making the refractive index a little bit high. Further, the device has a V-shaped groove 3 consisting of an optically polished end surface 4 which is perpendicular to the surface of the substrate 1 and also perpendicular to the traveling direction of the light and an optically polished reflecting surface 5 which is at 45 deg. to the end surface 4.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide device, and more particularly to an optical waveguide device configured to extract light perpendicularly to a substrate surface.

0002

[Prior Art] Conventionally, when extracting light from an optical waveguide,
As shown in FIG. 4, by placing the prism 11 on the optical waveguide 2, the prism 11 and the optical waveguide 2 are coupled,
There is an optical waveguide device that extracts light (outgoing light) 12 from a prism 11. Furthermore, as shown in FIG. 5, there is an optical waveguide device in which a diffraction grating 13 is formed on the surface of the optical waveguide 2 and light (output light) 12 is extracted from the optical waveguide 2 at a specific angle. In addition, in FIGS. 4 and 5, 1 is a substrate, 8 is incident light, and 10 is transmitted light.

0003

[Problems to be Solved by the Invention] However, the conventional technology has the following problems.

(1) In the prism coupling shown in FIG. 4, light is extracted by coupling between the optical waveguide and the prism.
Light cannot be extracted perpendicularly to the optical waveguide surface.

(2) According to the diffraction grating shown in FIG. 5, radiation loss increases in order to extract light perpendicularly to the surface of the optical waveguide.

(3) According to the diffraction grating shown in FIG. 5, an accuracy of 1 μm or less is required to create the diffraction grating, which is extremely difficult to create.

[0007]

[Means for Solving the Problems] The optical waveguide device of the present invention includes:
A substrate made of a material that transmits light, an optical waveguide formed by slightly increasing the refractive index on this substrate, and an optical waveguide that is perpendicular to the surface of the substrate and perpendicular to the direction of propagation of light. 45° to the polished end face and said end face.
and an optically polished reflective surface having an angle of .

Further, the optical waveguide device of the present invention includes a substrate made of a material that transmits light, an optical waveguide formed on the substrate by slightly increasing the refractive index, and a an optically polished end face that is perpendicular to the direction of propagation of the light and 45° to said end face;
a V-shaped groove having an angle of , and a mirror surface on which a metal layer and a glass layer are deposited.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

Referring to FIG. 1 showing a first embodiment of the present invention, titanium is patterned into a desired optical waveguide shape on the surface of a LiNbO3 substrate 1 using photolithography, and the titanium is further thermally diffused. The optical waveguide 2 is created by this. Next, a part of the optical waveguide 2 is mechanically cut to form a V-shaped groove 3. One surface of the V-shaped groove 3 is an optically polished end surface 4 that is perpendicular to the direction in which the light travels, allowing the incident light 8 propagating through the optical waveguide 2 to propagate into space without loss. The spatially propagated light passes through the reflected light 9 that is reflected perpendicularly to the substrate 1 on the optically polished reflective surface 5 that has an angle of 45° with respect to the end surface 4, and is reflected again. Transmitted light 10 propagating through the optical waveguide 2
It is divided into two parts. With this configuration, the light propagating through the optical waveguide 2 can be extracted perpendicularly to the substrate 1. Furthermore, the incident light 8 can be divided into reflected light 9 and transmitted light 10 with less loss. Furthermore, the depth of the V-shaped groove 3 is 20μ.
m, and does not require the precision required to create a diffraction grating on the optical waveguide 2.

2 and 3 showing a second embodiment of the present invention
Referring to , an optical waveguide 2 is created by patterning titanium into a desired optical waveguide shape on the surface of a LiNbO3 substrate 1 using photolithography technology, and then thermally diffusing the titanium. Next, a part of the optical waveguide is mechanically cut to form a V-shaped groove 3. One surface of the V-shaped groove is an optically polished end surface 4 that is perpendicular to the traveling direction of the light, and allows the incident light 8 propagating through the optical waveguide 2 to propagate into space without loss. The light that propagated in space is
A mirror surface (reflection surface) 5 having an angle of 45° with respect to the end surface 4
0, the reflected light 9 is reflected perpendicularly to the substrate 1 without loss.
becomes. As is clear from FIG. 3 showing an enlarged configuration of the V-shaped groove 3, the mirror surface 50 has an angle of 45° with respect to the end surface 4.
consists of a metal layer 51 and a glass layer 52 deposited using sputtering techniques. In this configuration, the optical waveguide 2
The light propagating through the substrate 1 can be taken out perpendicularly to the substrate 1 without any loss. Further, the depth of the V-shaped groove 3 is about 20 μm as in the first embodiment, and the precision required to form a diffraction grating on the optical waveguide 2 is not required.

0012

[Effects of the Invention] As explained above, according to the present invention, by providing a V-shaped groove in the optical waveguide, the light propagating in the optical waveguide can be extracted perpendicularly to the substrate without loss. can. Furthermore, the precision required to create a diffraction grating on an optical waveguide is not required.

[Brief explanation of drawings]

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

FIG. 2 is a sectional view showing a second embodiment of the invention.

FIG. 3 is a sectional view showing a second embodiment of the invention.

FIG. 4 is a sectional view showing a conventional example.

FIG. 5 is a sectional view showing a conventional example.

[Explanation of symbols]

1　　　　Substrate 2 Optical waveguide 3 V-shaped groove 4 End face 5 Reflective surface 8 Incident light 9 Reflected light 10 Transmitted light 50 Mirror surface 51 Metal layer 52 Glass layer

Claims (2)

[Claims] 1. A substrate made of a material that transmits light, an optical waveguide formed on this substrate by slightly increasing the refractive index, and a direction perpendicular to the surface of the substrate and in which light travels. a V-shaped groove comprising an optically polished end face perpendicular to said end face and an optically polished reflective face at an angle of 45° to said end face. wave device. 2. A substrate made of a material that transmits light, an optical waveguide formed on this substrate by slightly increasing the refractive index, and a direction perpendicular to the surface of the substrate and in which light travels. a V-shaped groove comprising an optically polished end face perpendicular to said end face and a mirror face having a metal layer and a glass layer deposited thereon and at an angle of 45° to said end face. optical waveguide device.