JPS63300217A - Temperature control type light guide - Google Patents

Abstract

PURPOSE:To lower electric power consumption and to prolong the life of the titled light guide by forming the light guide in the central part on the surface layer of a quartz substrate, covering the entire surface including this light guide with a buffer layer, providing a heater 4 facing the light guide thereon and constituting a protective layer of a low heat conductive material at the time of covering the entire surface with the protective layer. CONSTITUTION:The light guide 2 is formed to several-10mum at the center in the surface layer part of the substrate 1 consisting of quartz glass or the like by diffusion or ion exchange of Ti and the entire surface including this light guide is covered with the SiO2 buffer layer 3 of about 4mum thickness. The heater 4 having nearly the same size as the size of the light guide 2 is provided thereon so as to face the light guide and the SiO2 layer 5 having low heat conductivity is deposited over the entire surface inclusive of said heater while the thickness thereof is adjusted to about the same size as the depth of the light guide 2. Then, the heater 4 is merely required to increase the temp. by 20 deg.C at the most at the time of energizing the heater 4 to increase the temp. of the light guide 2. The electric power consumption of the temp. control type light guide is thus decreased and since the temp. is shut off by the protective layer 5, the longer life is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] In a temperature-controlled optical waveguide, at least the heater is coated with a layer of low thermal conductivity for low power control 'Bl.

[Industrial application field]

The present invention relates to an optical waveguide, and particularly to a guiding waveguide that utilizes changes in refractive index due to temperature changes.

[Conventional technology]

A waveguide formed by introducing titanium (Ti), for example, into a substrate such as quartz glass by diffusion or ion exchange is used. The so-called glass waveguide is generally
It utilizes the change in optical path length based on the change in refractive index caused by applying a temperature change to the waveguide or its vicinity. This guide wavepath is used to construct a temperature-controlled optical switch, for example. In order to provide the above-mentioned temperature change, a heater is provided on or near the waveguide along the waveguide.

[Problem that the invention seeks to solve]

The heater of the optical switch described above consists of a thin film of gold or copper deposited on top of the waveguide. Normally, since this heater has a structure in which it comes into direct contact with air, the heat generated is not efficiently used for heating the waveguide. As a result, large amounts of power are required to produce the required temperature changes, and
The heater itself suffers from air oxidation due to overheating and deteriorates, resulting in a short lifespan.

(Means for solving the problems) The problems with the conventional temperature-controlled optical waveguide described above are as follows:
The present invention is characterized by having an optical waveguide formed on the surface of a substrate, a heater formed above, below, or near the optical waveguide, and an electrically insulating heat resistance layer formed at least on the heater. This problem is solved by optical waveguide.

[Effect]

In temperature-controlled waveguide optical switches.

By covering at least the heater with a heat resistance layer, it is possible to provide an optical switch with lower control power and longer life.

〔Example〕

, FIG. 2 is a diagram showing the principle structure of a conventional temperature-controlled optical waveguide for comparison. An optical waveguide 2 is formed by introducing titanium or the like into a substrate 1 made of quartz glass or the like using a method such as diffusion or ion exchange. On the surface of the substrate 1 on which the optical waveguide 2 is formed, a material 1 having a slightly lower refractive index than the optical waveguide 2 is usually made of silicon dioxide (Si02), which is the same as the quartz of the substrate 1. thickness 4
A buffer layer 3 having a thickness of approximately μm is formed.

Further, on top of the buffer N3, there is a heater 4 made of a gold (Au) thin film, for example, several microns wide and several thousand thick.
It is provided directly above the optical waveguide 2 or in the vicinity of the optical waveguide 2. In the figure, 141 and 42 are a lead wire portion and a terminal portion of the heater 4, respectively. Heater 4
By applying current and heating, the temperature of the waveguide portion of the substrate 1 is increased. As a result, the refractive index of this waveguide portion changes, and the effective optical path length of the waveguide changes. This guide waveguide can be constructed into a Matsuhatsu-Enda type waveguide, for example, and used as an optical switch.

FIG. 1 is a sectional view showing the structure of the temperature-controlled optical waveguide of the present invention. In the figure, the same parts as in FIG. 2 are given the same reference numerals.

As shown in the figure, in one optical waveguide of the present invention.

A protective layer 5 serving as a heat resistance layer is formed on the surface of the substrate 1 on which the heater 4 is provided. The protective layer 5 is equivalent to the portion of the optical waveguide 2 of the substrate l, or.

Si having lower thermal conductivity 1, for example, has a thickness of several μm to about 108° C., which is about the same depth as the leading waveguide 2.
02 layer 1 is formed using conventional chemical vapor deposition (CVD) or other thin film techniques.

In the conventional optical waveguide shown in FIG. 2, most of the heat generated from the heater 4 was directly dissipated into the atmosphere.
By introducing the above protective layer 5, at least half of the light flows to the optical waveguide 2 side.

contributes to the temperature rise. As a result, conventionally, the optical waveguide 2
In order to cause a predetermined change in the refractive index in the part, it was necessary to supply power so that the temperature of the heater 4 would be 9, for example, 100°C. In order to do so, it is sufficient to raise the temperature of the heater 4 by at most 20° C. above room temperature.

As mentioned above, according to the temperature-controlled optical waveguide of the present invention,
Lower power operation is possible compared to conventional leading waveguides. Further, since the operating temperature of the heater 4 is lowered and it is isolated from the atmosphere by the protective layer 5, a longer life is achieved.

〔Effect of the invention〕

According to the present invention, it is possible to provide a low-power, long-life, temperature-side fIII type optical waveguide.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of a temperature-controlled optical waveguide according to the present invention. FIG. 2 is a diagram showing the principle structure of a conventional temperature-controlled rate sensor for comparison. In fig. 1 is the board. 2 is the leading wave path. 3 is the buffer layer. 4 is a heater. 5 is a protective layer. 41 and 42 are a lead wire portion and a terminal portion of the heater 4, respectively. Follow - the meaning of the pot Heshi parable 2 Kasumi

Claims (1)

[Scope of Claims] An optical waveguide formed on the surface of a substrate, a heater formed above, below, or near the optical waveguide, and an electrically insulating heat resistance layer formed at least on the heater. A temperature-controlled optical waveguide characterized by: