JPS60178408A - Optical waveguide - Google Patents

Abstract

PURPOSE:To reduce cost by covering a material to be formed as an optical waveguide which allows transmission of light at a low loss with a material which reflects light at low loss without using a costly semiconductor single crystal wafer. CONSTITUTION:For example, blue sheet glass, white sheet glass, molten quartz or the like is used for a substrate 1 and a metallic film 2 deposited by evaporation is selectively formed on the part of the substrate 1 to be used as the bottom of an optical guide. A material which does not change in the stage of forming a material 4 to be used as an optical waveguide, for example, Ni, Cr, W, Mo, Ti, N, Ta or the like which does not change at the forming temp. of SiO2 or during glow discharge if the material 4 is SiO2 is used for the film 2. Another metallic film 15 to be deposited by evaporation is formed on the film 2 so as to overlap partly or wholly thereon. A material which is liable to diffuse during or after the formation of the material 4 is selected for the film 15 and is diffused into the material 4, by which a diffused layer 5 to serve as a wall of the optical waveguide is formed. A metallic film 3 deposited by evaporation so as to be used as a cap is then formed. The optical waveguide which can transmit efficiently light is thus manufactured inexpensively.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an integrated circuit using light, and particularly to an optical waveguide used in a circuit integrated on a single substrate.

Conventional configurations and their problems Integrated circuits that use light have advantages such as high-speed calculations and low noise compared to those that use electrical signals, so there is a high demand for the development of low-cost manufacturing methods. 1 is there. Conventionally, single crystal wafers such as InP and GaAs have been used as substrates for optical integrated circuits.

These substrates are expensive and difficult to popularize.

OBJECTS OF THE INVENTION In view of the problems of the conventional example, an object of the present invention is to provide an inexpensive optical waveguide without using an expensive semiconductor single crystal wafer.

Structure of the Invention The present invention is to cover a material that becomes an optical waveguide that transmits light with little loss with a material that reflects light with little loss.KJ:
17 The cheapest option is to get the buttock, the mother-in-law, and the winter side.

Description of examples An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a cross section of an optical waveguide in a first embodiment of the present invention.

Reference numeral 1 denotes a substrate, and in this example, blue plate glass, white plate glass, fused silica, etc. were used. 2 and 3 are metal vapor deposited films that reflect light with little loss; in principle, the metal vapor deposit film 2 must not be altered or deformed during the formation of a substance 4 that transmits light. For example, if the material 4 that transmits light is Sio2, which is formed by decomposing SiH4 and 02 by a glow discharge decomposition method, Ni, Cr, W, Mo, Ti, Mn, which does not change at the formation temperature of S102 or during glow discharge.
, Ta, etc. may be used. The metal vapor deposited film 3 has no such limitations. Reference numeral 5 denotes a diffusion layer formed in the substance 4, which reflects light with little loss, such as a substance that easily diffuses into S s O 2 , such as metals such as Cu, Zn, and P.
d, Ag, Au.

This is a diffusion layer in which Al, In, Sn, etc. are diffused. With this configuration, an optical waveguide 6 made of the substance 4 is configured.

FIG. 2 shows an example of the configuration of an optical integrated circuit using this optical waveguide. 1 to 6 in FIG. 2 are the same as those in FIG. 1. For example, a metal plate 11 exhibiting good heat dissipation and conductivity is attached onto a substrate 1o different from the substrate 1o.

This serves as a heat sink and an electrode for a light emitting source 12, such as a semiconductor laser or a light emitting diode, which generates light that passes through the waveguide 6. Reference numeral 13 denotes a dielectric material necessary to introduce light from the light emitting source 12 into the optical waveguide with little loss, and its refractive index has a value between that of the light emitting source 12 and the refractive index of the optical waveguide 6. By attaching substrate 1 and substrate 10, an optical integrated circuit is completed. According to the configuration example shown in FIG. 2, the light from the light emitting source 12 is separated into four parts. Conversely, if a light receiving element is used instead of a light emitting source, it is clear that an AND circuit with four inputs will be used.

FIG. 3 explains the manufacturing process of this example.

Since the components are the same as those in FIG. 1, the same numbers are shown. A metal vapor deposition film 2 is selectively formed on a substrate 1 at a portion that will become the bottom of an optical waveguide. The metal vapor deposited film 2 is chosen to be one that does not change during the formation of the material 4 that will become the optical waveguide as described above. Another metal evaporation film 16 is formed on the metal evaporation BIA2 so as to partially or completely cover the metal evaporation BIA2 (FIG. 3a). As mentioned above, this metal vapor deposited film 15 is also selected from a material that is easily diffused during or after the formation of the material 4 that will become the optical waveguide.

The metal of this vapor-deposited film 16 is diffused into the substance 4 to form a diffusion layer 5 which becomes the wall of the optical waveguide. That is, after FIG. 3a, a material 4 that will become an optical waveguide is formed, and a metal vapor deposition film 3 that will become a lid of the waveguide is formed (FIG. 3b). For example 51
The case where 02 is used will be explained. Place the substrate in a vacuum device, maintain the substrate temperature at 100 to 500''C, and evacuate it to vacuum.
Adjust the flow rate and displacement to ~10 Torr. A direct current or high-frequency electric field is applied within a vacuum device to generate a glow discharge. SiH4 and 02 are decomposed by glow discharge, and a substance 4 made of Sio2 is deposited on the substrate 1. The discharge power is 1 mW/cd to IW/cd, and the SiO2 growth rate is 0.1 μm to 10 μηL/
It was h.

During the S zO 2 growth, the metal evaporated film 15 diffuses into the 5iO 24 and reaches the surface. In case of partial diffusion or insufficient diffusion, after forming 31024, the metal vapor deposited film 16
Heat it with strong light, etc. and diffuse it sufficiently. In this way, the diffusion layer 6 is formed. The metal vapor deposited film 3, which becomes the lid of the optical waveguide, is selectively etched to create a light inlet or a light outlet, resulting in a structure as shown in FIG.

The light inlet or the light outlet may have a cross section as shown in FIG. In addition, if the refractive index of the material whose refractive index can be easily changed in the thickness direction is increased, for example, by increasing the X value of SiO material as it approaches the substrate surface and the surface, the reflective metal vapor deposited films 2 and 3 on the bottom surface may disappear. good.

FIG. 4 shows a second example of creating a diffusion layer 5 that becomes the wall of an optical waveguide. In this embodiment, a material 4 that will become an optical waveguide is first deposited, and then a metal vapor deposited film 15 that will become a wall is deposited.
(Figure 4a).

Thereafter, the substrate is heated to diffuse the metal vapor deposited film 16 into the material 4 that will become the optical waveguide (FIG. 4b).

Thereafter, a metal vapor deposited film 3 which will become the lid of the optical waveguide is formed (FIG. 4C) and selectively etched to complete the process as shown in FIG. 1.

Even metals that are difficult to diffuse into 5iO24 can be diffused by strong heating. The third example described below uses this property to fabricate an optical waveguide wall. Without forming the metal vapor deposited film 15 that becomes a wall, the end portion of the metal vapor deposited film 2 that becomes the bottom is heated by irradiating strong light such as a laser beam. In this case, there is an advantage that the optical waveguide can be freely manufactured depending on the laser irradiation position.

In addition, in the above examples, E) by glow discharge decomposition method
102 film was used as the material for the optical waveguide, but S I H4
If NH3 is mixed with the S, iN film, a 5i
A SiC film can be produced by mixing CH4 with I(4).

Since these can sufficiently transmit visible light, it is clear that they can be used as optical waveguides, and depending on the wavelength of the light, amorphous silicon films or germanium films can also be used. It goes without saying that the above-mentioned thin film can be produced not only by the glow discharge decomposition method but also by the Spantary/G method and the thermal decomposition method.

Effects of the Invention As described above, the present invention provides an optical waveguide that can efficiently transmit light at low cost by creating a wall by diffusing a substance that reflects light, such as a metal, through a thin film that becomes an optical waveguide. can be created.

[Brief explanation of the drawing]

FIG. 1 is a structural sectional view of an optical waveguide according to an embodiment of the present invention, and FIG. 2 is a process diagram showing a method of emitting light using the optical waveguide of FIG. 1. 1.10...Substrate, 2...Metal vapor deposited film that will become the bottom of the optical waveguide, 3...Metal vapor deposited film that will become the lid of the optical waveguide, 4... ...Substance that transmits light with little loss, 5.. Diffusion layer that becomes the wall of the optical waveguide, 6.. Optical waveguide. Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure 3 (Yu・) and 2 Do Figure 4 (Nori! To? (C)

Claims (1)

[Claims] (1) A thin film layer that transmits light with low loss, a thin film layer that reflects light with low loss, and a layer that diffuses and reflects light with low loss in the thin film layer that transmits light with low loss are at least the constituent elements; An optical waveguide characterized in that the transmitting thin film layer is configured such that all surfaces except at least one surface are covered by the light reflecting thin film layer and the light diffusing layer. b) A thin film layer that reflects the light with little loss is provided on both sides of the thin film layer that transmits light with little loss, and a light reflecting layer is provided between the thin film layers that reflect the light that is diffused through the thin film layer that transmits the light. . A guiding waveguide characterized in that the light-transmitting thin film layer is surrounded by a light-reflecting thin film layer in a cylindrical shape.