JPS60243642A - Optical switch - Google Patents

Abstract

PURPOSE:To obtain an optical switch which is less in light quantity loss, and generates stable foams with simple constitution, by forming one-dimensionally plural optical waveguides on a substrate, providing a liquid loading part loaded with a liquid whose refractive index is equal to that of the optical waveguide, at a prescribed angle between the adjacent waveguides, and providing a heating means on said part. CONSTITUTION:Two optical waveguides 4a, 4b are formed on one straight line on a substrate 2. A liquid filling part 8 filled with a liquid whose refractive index is roughly equal to that of the optical waveguides 4a, 4b is provided between the optical waveguides 4a, 4b at an angle of 45 deg. to the optical waveguides 4a, 4b. On the lower part of the liquid filling part 8, a heating resistor 10 is provided, and a resistance protective layer 4, an electrode 16 and a top board 12 are provided. Light advancing in the optical waveguide 4a travels straight in the liquid filling part 8 and advances in the optical waveguide 4b. When a current is made to flow to the heating resistor 10 through the electrode 16, air foams 18 are generated in the liquid filling part 8, and the light advancing in the optical waveguide 4a is totally reflected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an optical switch that can electrically switch the direction of propagation of light.

[Prior art]

Optical switches that switch optical paths are generally classified into two types. That is, a town with an appropriate shape, a town ρII-rA, a mountain, and a moon can also be destroyed.
-+L? (7) Optical switches can be divided into optical switches that switch the optical path by disturbing the optical path, and optical switches that switch the optical path using electro-optic or magneto-optic effects and have no moving parts. The former type of optical switch has low insertion loss and high efficiency, but because it has mechanically moving parts, its switching speed is inferior to the latter type of optical switch.

On the other hand, the latter type of optical switch is LiNbO3
Many proposals have been made, including those using crystals, but all of them have the disadvantages of large insertion loss and small switching angle.

Therefore, an optical deflector has been devised in which the liquid is foamed to form air bubbles, and the light is totally reflected to change the path of the light depending on the presence or absence of the air bubbles. That is, the optical polarizer disclosed in Japanese Patent Publication No. 49-5475 has a configuration as shown in FIG. The liquid 104 is loaded into the transparent container 102, and the transparent container 1
A source medium 106 having a approximate oil contact ratio with the liquid 104 is provided so as to form an angle of approximately 45 degrees with 02, and this source medium 106
Foaming means 108 for vaporizing liquid 104 on surface 0
It has a configuration that provides. Foaming means 10 with this optical deflector
When no voltage is applied to the foaming means 108 (FIG. 4(a)), the incident light 110 travels straight; however, when a voltage is applied to the foaming means 108 (FIG. 4(b)), the liquid 104 is vaporized. ,
The vaporized bubbles 112 totally reflect the incident light 110, and the incident light 110 is totally reflected, resulting in the incident light 106 and the reflected light 114.
direction changes.

However, an optical deflector having such a configuration has a transparent container 1.
Since the optical medium 106 is provided at an angle of approximately 45 degrees to the wall surface of the optical deflector 02, the structure of the optical deflector itself is complicated and difficult to manufacture. Furthermore, even if the optical medium 106 is made of a transparent material, it is inevitable that light will be reflected to some extent when it passes through, resulting in a loss of light quantity. It had drawbacks such as an unstable shape.

〔the purpose〕

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned drawbacks, it is an object of the present invention to provide an optical switch that is simple in construction and capable of generating stable bubbles with little light loss.

〔composition〕

To achieve the above object (the present invention forms a plurality of optical waveguides in a one-dimensional shape on a substrate; forming between adjacent optical waveguides among the plurality of optical waveguides so as to form a predetermined angle with the optical waveguide; and forming a heat generating means for increasing the temperature of the liquid loading section between the substrate and the liquid loading section. It is characterized by

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings. FIG. 1 shows the first embodiment of the present invention.
is a plan view of the optical switch, (b) is a sectional view taken along line xx' of (,), and (C) is a sectional view taken along y-y' of (,). However, c) shows a state in which bubbles 18 are generated.

As shown in the figure (in this example, there are two optical waveguides 4 on the substrate 2).
Form a and 4b on a straight line. the optical waveguide 4a,
4b uses optical glass BK7.

A liquid loading section 8 loaded with a liquid 6 having an oil contact ratio approximately equal to the oil contact ratio (1, 51) of the optical waveguides 4m and 4b is provided between the optical waveguides 4a and 4b. As the liquid 6, benzene with an oil contact ratio of 1.50 is used.

Further, a heating resistor 10 is provided between the liquid loading section 8 and the substrate 2 as a heating means for increasing the temperature of the liquid 6 charged into the liquid loading section 8. Note that 12 is a top plate, 14 is a resistor protection layer that protects the heating resistor 10, 16 is an electrode of the heating resistor 10, and 18 is a bubble.

Next, the operation of the first embodiment will be explained based on FIG. 2. FIGS. 2(a) and 2(b) show a state in which the heating resistor 10 is generating heat and a state in which it has generated heat, respectively. When the heating resistor 10 is not generating heat, the inside of the optical waveguide 4a (FIG. 1) is
The light traveling in the direction also travels straight through the liquid loading section 8 and further straight through the optical waveguide 4b.

This is because the oil contact ratio n□ (1, 51) of the optical waveguide 4 and the oil contact ratio n2 (1, 50) of the liquid 6 are approximately equal, so the incident angle θ is the middle angle of incidence.

By the way, when a voltage is applied to the heating resistor 10 through the electrode 16, the bottom of the heating resistor 10 rises, and the liquid 6 above the heating resistor 10 vaporizes and foams. That is, air bubbles 18
occurs in the liquid loading section 8.

In this case, the light incident in the A direction is totally reflected at the interface between the optical waveguide 4a and the liquid loading section 8, as shown in FIG. 2(b), and travels in the B direction. This is because the conditions for total internal reflection in Figure 2(b) are multiplied by 3. Here, nl = 1.51 jn3 = 1. O
By substituting O (the refractive index of gaseous benzene), the above equation becomes θ1
〉41°. In this embodiment, the angle φ formed by the optical waveguide 4& and the liquid loading section 8 is set to 45°, so that θ=45°, and formula (1) is satisfied. That is, when bubbles 18 are generated, total reflection occurs as shown in FIG. 2(b).

In the embodiment described above, the optical waveguides 5a and 5b are used as the optical waveguides 4a and 4b.
Although benzene was used as the liquid BK7 and liquid 6, other combinations of FKI and carbon tetrachloride are also conceivable. That is, it goes without saying that the present invention is effective for any combination of optical waveguide material and liquid that satisfies the condition of formula (1).

In addition, in this example, the heating resistor 10K Ta2N,
8102 was used for the resistor protection layer 6 and Au was used for the electrode 16, and the optical switch according to this example was manufactured by a normal method for manufacturing a thermal head. Therefore, it is very easy to miniaturize and increase the integration of this element because the manufacturing method of a thermal head can be applied.

Further, when the incident direction is changed from A to C direction as shown in FIG. 2(b), the light is reflected in D direction. This can also be done by inputting light from the direction opposite to fiA.

Furthermore, as mentioned above, the optical switch according to the present invention can be made smaller and highly integrated, so by arranging the elements in an array and connecting a light source such as a laser diode to one end,
A very compact optical scanning element can be obtained.

FIG. 3 illustrates the optical scanning element as a second practical example of the present invention. FIG. 3 is a plan view of the optical scanning element, and as shown in the figure, a plurality of optical waveguides 4-2.4-2. ..., 4-(
N+1) is formed in a -dimensional shape, a liquid loading section 8 is provided between adjacent optical waveguides, one end of this liquid loading section 8 is all connected, and a heating resistor is installed between each liquid loading section 8 and a substrate (not shown). Body 111°10-2.・ , 1O-(N+1) is provided. 2° is a radar diode.

Here, a drive circuit (not shown) is connected to the heating resistor 10-1.
10-2.・By selectively applying power to =, 1O-(N+1), a bubble 18 is generated at an arbitrary position (in this example, the position 10-N) to change the traveling direction of the light and scan the light. I can do it.

〔effect〕

As described above in detail and specifically, the present invention provides the following effects.

(1) The configuration is simple because the heating resistor, optical waveguide, liquid loading section, and top plate are formed in layers on the substrate.

(2) There is almost no light loss.

(3) Since bubbles are generated within the liquid loading section, bubbles can be generated stably.

(4) Even if the direction of incidence is rotated by 180 degrees, it can function as a switch.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an optical switch according to the first embodiment of the present invention, (,) is a plan view, (b) is a sectional view taken along line X-x' of (,), and (C) is a y of (,). -, / is a sectional view. Fig. 2 is an explanatory diagram showing the operation of the first embodiment, Fig. 3 is a schematic configuration diagram of the second embodiment of the present invention, and Fig. 4 is a conventional optical polarizer Q.
It is a sectional view, and (,) shows a state in which no voltage is applied to the foaming means, and (b) shows a state in which a voltage is applied to the foaming means. In the figure, 2...substrate, 4a, 4b...optical waveguide, 6...
Liquid, 8...Liquid loading part, 1o...Heating resistor, φ
...It is a predetermined angle. @Figure 1 (b) (C)

Claims (1)

[Claims] (1) A plurality of optical waveguides are formed in a one-dimensional shape on a substrate; a liquid loading section loaded with a liquid having an oil contact ratio approximately equal to that of the optical waveguide is set at a predetermined angle with the optical waveguide. An optical switch characterized in that the optical switch is formed between adjacent optical waveguides among the plurality of optical waveguides; and a heat generating means for increasing the temperature of the liquid loading section is formed between the substrate and the liquid loading section.