JPS6136977Y2 - - Google Patents

Description

[Detailed explanation of the invention] (1) Field of the invention This invention is a thin film deflector mounted on a ceramic plate that utilizes the acousto-optic effect (Bragg diffraction phenomenon) in a thin film optical waveguide formed on the surface of a crystal substrate. The present invention relates to a light deflection device.

(2) Prior art and its problems Conventionally, this type of optical deflection device was constructed as shown in FIG. In the figure, numeral 10 is a crystal substrate constituting a thin film optical deflector, on the surface of which a thin film optical waveguide is formed, and a comb-shaped electrode 11 for propagating surface acoustic waves on the waveguide; a light input section 12 that introduces a light beam into the waveguide at a Bragg angle with respect to the surface acoustic wave; and a light output section 13 that guides the light beam Bragg diffracted by the surface acoustic wave from the waveguide. is formed. This crystal substrate 10 is bonded to the upper surface of a ceramic plate 20 serving as a substrate of the device, and is attached to a chassis 30 via this ceramic plate 20.
Terminals 21, 22, etc. are formed on the surface of the ceramic board 20 by ordinary printed wiring technology. Both ends of the comb-shaped electrode 11 on the crystal substrate 10 are bonded to terminals 21 and 22 of the ceramic plate 20 with wires, respectively. Further, a coil 40 is connected between the terminal 21 and the external connector 31.

The coil 40 is connected to the comb-shaped electrode 11 in order to efficiently generate surface acoustic waves. In other words, a drive circuit consisting of a high-frequency oscillator is connected to the comb-shaped electrode 11, and a high-frequency voltage is applied to it.The comb-shaped electrode 11 is almost equivalent to a capacitive capacitor, and the drive circuit for this capacitive load is Most of the incident power from the comb-shaped electrode 11 is reflected, and the power consumed by the comb-shaped electrode 11 becomes extremely small.
Therefore, a coil 40 is added between the comb-shaped electrode 11 and the drive circuit to increase the power consumed by the comb-shaped electrode 11.

By the way, there are various problems with the coil 40 and its mounting. First, the impedance of the comb-shaped electrode 11 includes variations due to manufacturing, and the inductance of the coil 40 required to maximize the power consumption of the comb-shaped electrode 11 is also not constant. Therefore, it is necessary to add a coil 40 having an optimum value for each comb-shaped electrode 11. It is very time-consuming and troublesome to create the optimum coil for each device and attach it as shown in FIG. 1 in this way. Further, as can be seen from FIG. 1, the space occupied by the coil 40 becomes large, and there is also the problem that the chassis 30 has to be made larger.

(3) Purpose of the invention The purpose of this invention is to provide an optical deflection device in which the above-mentioned coil necessary for maximizing the power consumption of the comb-shaped electrode is easy to implement, and its inductance can be easily adjusted. be.

(4) Structure and effect of the invention In order to achieve the above object, this invention forms a printed coil with a plurality of intermediate taps on the surface of the ceramic plate, and connects one end of the comb-shaped electrode with the printed coil. One end of the coil is connected, and the other end of the printed coil or a suitable intermediate tap is connected to a drive circuit.

According to the above configuration, since the coil is printed on the ceramic plate, the space it occupies is not a problem, and an extremely compact and high-density device can be realized. Furthermore, adjustment of the coil inductance according to the impedance of each comb-shaped electrode is very simple, as it is only necessary to select a tap.

(5) Description of Embodiment FIG. 2 shows an embodiment of the optical deflection device to which this invention is applied, and the chassis 30 in FIG.
Only the main parts are shown, excluding. A thin film optical waveguide is formed on the surface of the crystal substrate 10, and the above-described comb-shaped electrode 11, optical input section 12, and optical output section 13 are formed on the surface. A thin film optical deflector made of this crystal substrate 10 is bonded to the upper surface of a ceramic plate 20. Terminals 22 and coils 40 are previously formed in metal patterns on the upper surface of the ceramic board 20 by printed wiring. The printed coil 40 in this embodiment is formed into a crank shape. Terminals 41 are provided at both ends of the printed coil 40.
and 44 are formed respectively, and a coil 40
Two intermediate taps 41 and 43 are formed in the. One end of the comb-shaped electrode 11 is bonded to one end terminal 41 of the coil 40 with a wire, and the comb-shaped electrode 1
The other end of 1 is bonded to a terminal 22 with a wire. Then, the middle tap 41 of the coil 40,
Either the terminal 43 or the other end terminal 44 is connected to the connector as shown in FIG. 1, and then connected to the drive circuit. Terminals 42, 43 of the coil 40,
44 to be connected to the drive circuit is selected in accordance with the impedance of the comb-shaped electrode 11 of the thin-film optical deflector actually mounted so as to maximize the power consumed by the comb-shaped electrode 11. .

3A and 3B show other patterns of the printed coil 40 formed on the surface of the ceramic board 20, and it may be a circular spiral type as shown in the figure, or a rectangular spiral type. .

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the configuration of a conventional optical deflection device, Fig. 2 is a perspective view showing the main parts of an optical deflection device to which this invention is applied, and Fig. 3 is another pattern of a printed coil according to this invention. FIG. DESCRIPTION OF SYMBOLS 10... Crystal substrate, 11... Comb-shaped electrode, 12... Light input part, 13... Light output part, 20... Ceramic board, 4
0...Coil, 42, 43...Middle tap of coil 40.

Claims (1)

[Claims for Utility Model Registration] A thin film optical waveguide is formed on the surface of a crystal substrate, a comb-shaped electrode for propagating surface acoustic waves on the optical waveguide, and a light beam arranged at a Bragg angle with respect to the surface acoustic wave. An optical deflector in which a thin film deflector is mounted on a ceramic plate, the thin film deflector having a light input section for introducing the light beam into the waveguide, and a light output section for guiding the light beam blurred by the surface acoustic wave from the waveguide. In the device: A printed coil with a plurality of intermediate taps is formed on the surface of the ceramic plate, one end of the comb-shaped electrode and one end of the printed coil are connected, and the other end of the printed coil or a suitable intermediate tap is connected. An optical deflection device characterized in that the optical deflection device is connected to a drive circuit.