JPS6141132A - Optical switch apparatus - Google Patents

Abstract

PURPOSE:To eliminate mutual affection between two optical switches and to enhance the extent of integration by forming a groove on the base plate between the positions where the two thermal elements that individually switch different rays of light. CONSTITUTION:Optical waveguides 11 and 12 having high refractive index are built on base plate 10 and a heating electrode 13 in the section on the upper surface of the base plate 10 where said optical waveguides are not present, and in parallel with said optical waveguides 11 and 12, the other pair of optical waveguides 21 and 22 and the other heating electrode 23 are also built, and electrodes 13 and 23 are supplied with electric current from power supplies 14 and 24, respectively. When power is now supplied to heat the electrode 13, the section right under the electrode 13 and the refractive index becomes high, forming an optical path between waveguides 11 and 12. As a groove 30 was prepared between the electrodes 13 and 23, the heat is dissipated from the electrodes 13 and 23, whereby the heat generated at one electrode are not transmitted to the other electrode and whereby both electrodes are not mutually affected by heat generated at electrodes. Therefore, the mutual affection between two optical switches is eliminated and their extent of integration can be enhanced.

Description

BACKGROUND OF THE INVENTION [Technical Field of the Invention] The present invention relates to an optical switch device that utilizes thermo-optic effects.

[Description of prior art]

Optical switch devices that utilize thermo-optic effects include:
There are various methods such as those that change the refractive index by heat between two optical waveguides formed on a substrate with a thermo-optic effect, and switch the optical path between these two optical waveguides, or connect or disconnect the optical path. There is a type.

- As an example, let's consider an optical switch in which two optical waveguides are formed in the same line on a substrate, with their ends slightly heated. A heating element is provided between the ends of these optical waveguides. If the refractive index of the part of the substrate immediately below the heating element increases due to the heat generated by the heating element, this part becomes a type of optical waveguide because the refractive index of this part becomes higher than that of the surrounding area. Since an optical waveguide is formed between the ends of two optical waveguides formed with their ends separated, these two
The two optical waveguides are optically connected. That is, the optical switch is turned on and light in one optical waveguide can propagate to the other optical waveguide.

Consider a case where two such optical switches exist at adjacent positions on one substrate. When heat is generated from the heating element to turn on one optical switch, this heat is also conducted to the other adjacent optical switch. If one optical switch is kept on for a long time by keeping its heating element at a high temperature for a long time, the other optical switch will gradually become hot, and eventually this other switch will also turn on. It ends up. In addition, since the entire area including these two optical switch parts becomes high temperature, this entire area becomes an optical waveguide area, and the optical signal that is supposed to propagate through one optical switch part propagates to the other optical switch part. Situations like this also occur.

In order to prevent such switching chain effects and optical signal leakage between the two optical switches, it is necessary to provide a sufficiently large distance between the two optical switches. However, this requires a large area on the substrate, making it impossible to increase the degree of integration.

Summary of the Invention [Object of the Invention] The purpose of the present invention is to eliminate mutual influence between two optical switches formed on one substrate and to increase the degree of integration.

[Structure, operation, and effects of the invention]

The present invention is an optical switch device in which a thermal element is provided on a substrate having a thermo-optic effect, and the light propagating within the substrate is switched by changing the refractive index of the substrate due to heat generation or absorption of heat by the thermal element. It is characterized in that a groove is formed in the substrate between the positions where two thermal elements for switching, respectively, are provided.

The groove formed between the two thermal elements has the effect of blocking the heat conduction path between the two thermal elements and promoting heat dissipation by increasing the surface area. Thermal isolation between elements is improved. Therefore, 2 containing two thermal elements
There is no thermal interaction between the two optical switch parts, each switch part can achieve independent switching functions, and optical signal leakage is eliminated. In addition, since it is only necessary to have an area between two thermal elements to form a groove, the two thermal elements can be brought close to each other, and the degree of integration of the substrate can be increased.

This invention provides an optical switch device that deflects light using a refractive index gradient based on the temperature distribution of a substrate, an optical switch device that switches an optical path between optical waveguides formed on a substrate, or an optical switch device that disconnects an optical path, etc. It is applicable to all optical switch devices used. Furthermore, as the thermal element, not only a heat generating body but also a heat absorbing body such as a Peltier element can be used.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 3.

On a substrate QG having a thermo-optic effect, an optical waveguide 01) having a higher refractive index than the surrounding area is formed in a straight line. Opposing ends of these optical waveguides U and O2 are slightly layered, and a heating electrode 0J is formed on the upper surface of the portion where the optical waveguide does not exist. A heating current is applied to the heating electrode f131 by the power source 041 via the switch 051.

Similarly, on the substrate aO1, two linear optical waveguides f21) (22) are connected to the above-mentioned optical waveguide (11).
It is formed parallel to Q2+. There is also a slight layer between the opposing ends of the optical waveguide (Mold) and Co., Ltd., and a heating electrode is formed on the part where the optical waveguide does not exist. A heating current is applied to the heating electrode f23+ by the power source 0141 via the switch (25).

An R gloss is formed between the heating electrode (13) and the heating electrode (13). The size, depth, shape, etc. of the groove (2) are appropriately determined so as to produce the desired thermal isolation effect. If necessary, grooves may be formed on the sides opposite to the grooves, sandwiching the heating electrode uii.

For example, L i N b O3 crystal is used as the substrate (10). Optical waveguide Ql) tJ7J c21+
(2) is created by, for example, the substrate (101 surface - Ti
was deposited or sputtered, a waveguide pattern made of Ti was formed using this Ti film by a lift-off method, and the Ti was further heated at 970° C. for 5 hours in an oxygen atmosphere.
This is done by diffusing heat into the substrate 0. groove[
The phase] can be formed, for example, by the following method. After forming an optical waveguide by thermal diffusion of Ti, the substrate 0
0) Spin code a photoresist on the surface, and form a window in the resist at the part where the groove is to be formed by exposing it to light using a photomask and developing the resist. Then, argon ions are made to collide with the substrate 0 through the window by sputtering to form a groove in the window. Alternatively, after forming a resist window, the portion of the window 1 is etched using a heated etching solution HF + HNO3 to form a groove 2. The grooves can also be formed by electron beam processing, ultrasonic processing, or the like. The heating electrode a31i is, for example, AI! It is formed by sputtering or vapor deposition. Ni is used as a heating element.

Cr etc. are also used.

Since the optical waveguides 01) and 02 are disconnected, there is almost no propagation to the heat generating waveguide (12).When the heat generating electrode 03 is energized and the heat generating electrode α3 generates heat, the part directly under the electrode α3 is heated. Its refractive index increases. As shown by the chain lines in Figures 2 and 3, there is a part with a higher refractive index than the surrounding area, which becomes a type of optical waveguide, so an optical path is formed between optical waveguides 01) and 1. Therefore, the optical signal of the optical waveguide 01) propagates to the optical waveguide 02.

The heat immediately below the heating electrode 03 is radiated to the surroundings as shown by arrows in FIG. 3, and a portion of the heat is radiated into the atmosphere from the wall surface of the groove (2). Since the heat conducted around the bottom of the groove 00) has a long conduction distance, the temperature gradually decreases, and the heat is radiated into the atmosphere from the bottom of the groove 2. Therefore, the influence of the heat generated from hitting the heat generating electrode on the other optical switch (the part immediately below the heat generating electrode @) becomes very small.

Note that the operation of the optical switch consisting of the optical waveguide clIl and the heating electrode (to) is also the same as described above.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, 0th ω...
Substrate, αDa21 (211■... optical waveguide, oJ (to)... heating electrode, (to)... 9 grooves. Patent applicants: 4 people other than Tateishi Electric Co., Ltd.

Claims (1)

[Claims] In an optical switching device, a thermal element is provided on a substrate with a thermo-optic effect, and the light propagating within the substrate is switched by changing the refractive index of the substrate due to heat generation or absorption of heat by the thermal element. 2 to do
1. An optical switch device characterized in that a groove is formed in a substrate between positions where two thermal elements are provided.