JPH01133029A - Acoustooptic element - Google Patents

Abstract

PURPOSE:To facilitate application of the title element to a light guide type optical integrated device and to eliminate the restriction of a light guide material by providing a substrate in which the thickness changes in the perpendicular direction are distributed partially or over the entire part in the direction of the main face and an ultrasonic transducer provided on the surface intersecting with the main face of the substrate. CONSTITUTION:An ultrasonic flux 24 to be acted on the light waves propagating in the light guide 22 is generated by the ultrasonic transducer 23 provided on the surface intersecting with the main face of the substrate 21 having the light guide 22 on the main face. The thickness changes in the direction perpendicular to the main face of the substrate 21 are distributed partially or over the entire part in the direction of the main face and, therefore, the ultrasonic flux 24 excited by the ultrasonic transducer 23 can be propagated into the light guide 22 provided on the main face of the substrate 21. The application of this optical element to the light guide type optical integrated device is thereby facilitated and the restriction on the light guide material is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a so-called acousto-optic device that utilizes the interaction between ultrasonic waves and light waves.

BACKGROUND OF THE INVENTION Conventionally, this type of acousto-optic device has had a configuration as shown in FIG. In FIG. 2, 1 is an acousto-optic medium, 2 is an ultrasonic transducer provided on the main surface of the acousto-optic medium 1,
3 is a schematic representation of an ultrasonic bundle emitted from an ultrasonic transducer, 4 is an incident light, 5 is a diffracted light, and 6 is a transmitted light. The ultrasonic beam 3 emitted from the acousto-optic medium 1 forms a diffraction grating inside the acousto-optic medium 1, so that the incident light 4 incident from a suitable direction is diffracted by the diffraction grating to generate diffracted light 5. Further, when the excitation of the ultrasonic transducer 2 is stopped, the diffracted light 5 is extinguished and only the transmitted light 6 remains. Applying such a control effect on the intensity of diffracted light, this type of acousto-optic element is used as an external modulator for gas lasers, etc., and has been put into practical use, for example, in laser printers.

As another method, an optical waveguide type acousto-optic element having 16 configurations as shown in FIG. 3 has been proposed. In FIG. 3, 11 is a substrate, 12 is an optical waveguide formed on the surface of the substrate 11, 13 is an ultrasonic transducer consisting of comb-shaped electrodes formed on the optical waveguide 12, and 14 is a schematic diagram of radiation emitted from the ultrasonic transducer. The ultrasonic flux expressed in 15
is incident light, 16 is diffracted light, and 17 is transmitted light. The ultrasonic transducer 13 uses a piezoelectric material as the material of the optical waveguide 12 and applies a voltage using a comb-shaped electrode.
It excites ultrasonic waves (elastic waves). In operation, the ultrasonic beam 14 emitted from the ultrasonic transducer 13 forms a diffraction grating in the optical waveguide 12 provided on the substrate 11, so that when incident light 15 is irradiated from an appropriate direction, diffracted light 16 is generated. Occur. Furthermore, when the excitation of the ultrasonic transducer 14 is stopped, the diffracted light 16 is extinguished and only the transmitted light 17 remains.

Problems to be Solved by the Invention Such a conventional configuration, for example the example shown in FIG. It is difficult to incorporate it into devices such as Furthermore, in the example shown in Fig. 3, ultrasonic waves are excited by applying an electric field to the surface of a piezoelectric material using interdigitated electrodes provided on the surface of an optical waveguide as an ultrasonic transducer, and the optical waveguide material must have piezoelectricity. Therefore, there was a problem in that there were limitations in terms of material composition.

The present invention solves these problems, and aims to provide an acousto-optic element that can be easily applied to an optical waveguide type integrated optical device and has no restrictions on the selection of substrates or optical waveguide materials. be.

Means for Solving the Problems In order to solve the above problems, the present invention provides two-dimensional or three-dimensional
A substrate having a main surface provided with a three-dimensional optical waveguide, and a thickness variation in the direction perpendicular to the main surface is partially or entirely distributed in the direction of the main surface, and a substrate intersecting the main surface of the substrate. The device is equipped with an ultrasonic transducer mounted on the surface of the device.

Effect With the above configuration, the ultrasonic flux that acts on the light waves propagating in the optical waveguide can be applied not by the comb-shaped electrode but by the ultrasonic beam provided on the surface intersecting the main surface of the substrate having the optical waveguide as the main surface. Since it is generated by a sonic transducer, it is possible to widen the practical range of ultrasonic frequencies to be excited.

Further, by distributing the thickness change in the direction perpendicular to the main surface of the substrate partially or entirely in the direction of the main surface, the ultrasonic flux excited by the ultrasonic transducer is provided on the main surface of the substrate. This makes it possible to propagate the ultrasonic wave into the optical waveguide, and interaction between the optical wave and the ultrasonic wave can be realized within the optical waveguide.

Example An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a perspective view of an acousto-optic device showing an embodiment of the present invention. In FIG. 1, 21 is a substrate, 22 is a substrate 21
The substrate 21 is a two-dimensional or three-dimensional optical waveguide provided on the main surface, and the thickness variation in the direction perpendicular to the main surface is partially or entirely distributed in the direction of the main surface. 23
is an ultrasonic transducer provided on a surface intersecting the main surface of the substrate 21, and 24 is a schematic representation of an ultrasonic flux emitted from the ultrasonic transducer 23, where the thickness change in the direction perpendicular to the main surface is the main surface. Since the optical waveguide 22 is provided on the substrate 22 distributed in the direction of , the ultrasonic beam 24 is formed within this two-dimensional or three-dimensional optical waveguide 22 . 25 is incident light, 26 is diffracted light, and 27 is transmitted light.

The closing operation of the acousto-optic element configured as described above will be described below. An optical waveguide 22 is provided on the main surface of the substrate 21, and light propagates while being confined within the optical waveguide 22.

Further, since the substrate 21 is provided with an ultrasonic transducer 23 intersecting with the main surface on which the optical waveguide 22 is provided, the ultrasonic beam 24 can be emitted in the direction of the main surface of the substrate 21, and Since the thickness of the substrate 21 is distributed in a tapered manner in the direction of the principal surface of the substrate 21 in FIG. That will happen. Therefore, a diffraction grating is formed in the optical waveguide 22 by the ultrasonic beam 24 propagating in the optical waveguide 22. Therefore, the incident light 25 entering from a suitable direction is diffracted by the ultrasonic beam 24 and generates diffracted light 26. Moreover, if the excitation of the ultrasonic transducer 23 is stopped,
The diffracted light 26 is extinguished and only the transmitted light 27 remains. By applying the above operation, it becomes possible to suppress light waves propagating inside the optical waveguide 22.

Effects of the Invention As described above, the present invention has a main surface provided with four two-dimensional or three-dimensional optical wave paths, and the thickness change in the direction perpendicular to the main surface partially extends in the direction of the main surface. By having a substrate distributed over the entire surface of the substrate and an ultrasonic transducer provided on a surface intersecting the main surface of the substrate, it can be used as an acousto-optic element that controls light waves propagating in an optical waveguide type optical device. , the excitation range of the ultrasonic frequency used can be widened, and it can also operate at low frequencies, so the drive circuit can be constructed at low cost. This has the effect of eliminating the restriction that a piezoelectric material must be used for the wave path surface.

[Brief explanation of the drawing]

FIG. 7 is a perspective view showing an acousto-optic device according to an embodiment of the present invention, and FIGS. 2 and 3 are perspective views showing conventional acousto-optic devices, respectively. 21... Substrate, 22... Optical waveguide, 23... Ultrasonic transducer, 24... Ultrasonic bundle, 25...
Incident light, 26... Diffracted light, 27... Transmitted light. Agent Morimoto Zan Hiroshi 1st figure 21...en n-・Maruki rika 2 yo-atshi skin torashi person shi-su 24-, super person 9ri 2 east gar 2＼kaku γ6- 2 ot -1 ward] Takemeichi 27-... 9 (tsu (light) Figure 2 Figure 3-

Claims (1)

[Claims] A substrate having a main surface provided with a one-, two-dimensional, or three-dimensional optical waveguide, and a thickness variation in a direction perpendicular to the main surface is partially or entirely distributed in the direction of the main surface; An acousto-optic element comprising an ultrasonic transducer provided on a surface intersecting the main surface of the substrate.