JPS60254102A - Manufacture of optical circuit element - Google Patents

Abstract

PURPOSE:To uniform the temperature distribution of the optical circuit element by providing a light shield layer in contact with at least electrodes on the substrate surface of the optical circuit element. CONSTITUTION:The optical circuit element which has an optical waveguide 2 and electrodes 3 formed on a substrate 1 is provided with the light shield material layer 4 of, for example, a black paint with high heat absorptivity. The light shield material layer 4 may be adhered on an electrode part, over the entire surface of the substrate, or to the reverse side of the substrate 1. When external heat is applied to this element, the light shield layer 4 becomes hot firstly. The metallic electrodes 3 have high heat conductivity, so the inside of the light shield material layer short-circuits thermall including the electrodes. Consequently, the temperature difference is eliminated and the external heat is relaxed.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a method for manufacturing an optical circuit element, and more specifically, a method for manufacturing an optical circuit element by uniformly absorbing and dissipating heat through radiant heat etc. to maintain an average temperature within the element. The present invention relates to a method of forming a light-shielding material for use in light-blocking materials.

(2) Background of the technology As optical communication technology becomes more widespread, the elements used there tend to become more diverse. The environments in which these parts are used are harsh and changing conditions such as high temperatures, low temperatures, and high humidity, and research into elements that can withstand these conditions is actively underway.

A waveguide device is a device in which a light guide (waveguide) is formed on a flat substrate and an integrated optical circuit element is provided therein, and is formed for the purpose of mass production, miniaturization, and integration.

An example of this is an optical switch made of lithium niobate (
Titanium (Ti) is deposited on a LiNb03) substrate by vapor deposition, a waveguide is created by thermal diffusion, and electrodes are provided on the waveguide to provide a switch or modulation function.

(3) Prior art and problems By the way, it has been experienced that the original properties of optical circuit elements change when subjected to temperature cycles. Electrodes are made of metal materials and generate heat by absorbing not only light but also radiant heat.The heat release (absorption) coefficient of metal electrodes is different from that of the surrounding substrate without metal, and as a result, the electrodes Feeling hot or cold locally.

The width of the waveguide is, for example, on the order of 4 μm, and the width is on the order of 4 μm.
Since they are arranged at intervals of 7 μm, they are strongly affected by the temperature non-uniformity described above, which is also a cause of changes in the characteristics of the optical circuit element.

(4) Purpose of the Invention In view of the above-mentioned conventional problems, an object of the present invention is to provide an optical circuit element with uniform temperature distribution.

(5) Structure and object of the invention According to the present invention, an optical circuit element is provided with a light shielding material layer in close contact with at least an electrode on the surface of the substrate of the optical circuit element made of a plurality of materials. This can be achieved by providing a manufacturing method, and a buffer layer may be formed between the light shielding material layer and the optical circuit element substrate using a protective material having electrical, optical, and chemical insulation properties.

(6) Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

When a temperature change occurs outside, this change is transmitted to the element as conductive heat or radiant heat. At this time, when the element is made of different materials, each material has a different heat absorption coefficient and conductivity, so a temperature distribution occurs in the element.

Since the refractive index of a substance usually changes due to temperature changes, a refractive index distribution follows the temperature distribution. Such a refractive index distribution is often important in optical circuit elements. In order to eliminate this, in the present invention, a light shielding material is provided in close contact with the element inside the housing.

FIG. 1 shows an optical waveguide 2 and an electrode 3 made on a LiNbO3 substrate 1. Electrodes are usually aluminum (^β)
It is formed by vapor depositing metals such as Such a board is made of SUS,
It is placed on a table made of glass or Al.

When heat is applied to this element from the outside, for example when it is irradiated with a lamp or the surroundings become high temperature, the electrode portions are selectively heated because the metal used for the electrodes 3 has a high heat absorption efficiency. As a result, the refractive index under the electrode changes and this switching characteristic is adversely affected.

In contrast, according to the present invention, a light shielding material layer 4 is provided as shown in FIG. For example, black paint with high heat absorption rate is used as the light shielding material. Then, the temperature distribution inside the element becomes uniform, and since the electrode metal has high thermal conductivity, the temperature distribution of the surface layer of LiNbO31 becomes uniform within the plane. Note that in FIGS. 2 and 3, the same parts as those already illustrated are designated by the same reference numerals.

The light shielding material was made of black material with high radiant heat absorption rate,
First, the light shielding material layer 4 becomes hot. Since the metal electrode 3 has high thermal conductivity, the inside of the light shielding material layer including the electrode is thermally short-circuited. As a result, there is no temperature difference, and heat from the outside is alleviated.

When there is no light-shielding material layer, the transparent radiant heat passes through the electrode and reaches the waveguide 2 below, causing a change in the refractive index of that part as described above, which affects the characteristics of the element. It is.

The light shielding material layer 4 may be deposited only on the electrode portions, on the entire surface of the substrate, or on the back side of the LjNbOa substrate 1 as shown in FIG.

FIG. 3 shows another embodiment of the present invention, in which a buffer layer 5 is further provided below the light shielding material layer 4. Buffer N5 is made of alumina (An2.03) or silicon dioxide (5302). By providing the buffer layer, the element is electrically, optically, and chemically insulated and protected from oxidation, humidity, etc., and has the effect of preventing leakage due to the conductivity of the material used for the light shielding layer.

(7) Effects of the Invention As explained in detail above, according to the present invention, by providing a light-shielding material layer in close contact with the optical circuit element, the temperature distribution inside the optical circuit element is made uniform, and heat from the outside is This is highly effective in preventing changes in device characteristics. Note that the materials for the light-shielding material and the buffer layer are not limited to the above examples, and can be appropriately selected in consideration of the type of optical circuit element and the environment in which it is used.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a partial cross section of a bipolar optical switch, and FIGS. 2 and 3 are cross sectional views of an embodiment of the present invention. 1-LiNbO3 substrate, 2-waveguide, 3-electrode, 4-light shielding material layer, 5-buffer layer Fig. 1 Fig. 3

Claims (1)

[Scope of Claims] +11 A method for manufacturing an optical circuit element, characterized in that a light-shielding material layer is provided in close contact with at least an electrode on the surface of a substrate of an optical circuit element made of a plurality of materials. (2) There is an electrical connection between the light shielding material layer and the optical circuit element substrate.
2. The method according to claim 1, wherein the buffer layer is formed of a protective material having optical and chemical insulating properties.