JPH03163534A - Optical deflecting element - Google Patents

Abstract

PURPOSE:To provide the element which is lower in electric power consumption, larger in deflection angle and higher in performance by laminating plural pieces of unit base materials, each having a thin-film layer consisting of an electrode layer and insulating layer adjacent to the opposite outside surfaces of an electrooptical layer via edge parts inclined with incident light, and connecting a driving power source which impresses a voltage to the electrooptical layer to the electrode layers. CONSTITUTION:The unit base materials 13, each formed with the thin-film layer 17 consisting of the electrode layer 15 and insulating layer 16 adjacent to the opposite outside surfaces of the flat plate electrooptical layer 14 via the edge parts inclined with the incident light are provided and plural pieces of the unit base materials 13 are integrally laminated and formed in the film thickness direction. The driving power source for impressing the voltage to the electrooptical layers 14 is connected to the electrode layers 15. The refractive index of the electrooptical layers 14 inversely proportional to the inter-electrode distance increases in proportion to the impressed voltage and, therefore, the larger deflection angle than the impressed voltage is obtd. and the number of resolving points is increased by increasing the thickness of the device and expanding the beam diameter. Thus, the high-performance optical deflecting element 12 having the small electric power and the large deflection angle is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical deflection element that performs optical path switching using electro-optic effects.

BACKGROUND OF THE INVENTION In recent years, optical deflection elements that utilize an acousto-optic effect and mechanically drive prisms or optical fibers have been proposed. However, since it is difficult to achieve high-speed optical deflection with these mechanisms, it is being considered to utilize electro-optic effects to perform optical deflection.

Therefore, as a conventional example of such a light deflection element, the device disclosed in Japanese Patent Application Laid-open No. 192926/1983 is
This will be explained based on the diagram and FIG. This optical deflection element 1 is formed by integrally joining two electro-optic elements 2 and 3, each of which has a triangular prism shape and whose optical axes are opposite to each other, to form a rectangular parallelepiped element pair 4. Each element 2 of element pair 4,
Optical fibers 5 to 8 forming an optical transmission path are connected to opposing surfaces corresponding to the third end surface, and electrode layers 9 and 10 are formed on the opposing surfaces having the boundary between each element 2 and 3 of the element pair 4. The drive power source 11 is connected to the drive power source 11. The optical fibers 5 to 8 are composed of a pair 5, 7 whose optical axes coincide with each other, and fibers 6, 8 adjacent to these, respectively.

In such a configuration, the optical deflection element 1 is connected to the electrode layer 9,
When no voltage is applied between each electro-optical element 2.
3 have the same refractive index, the light emitted from the optical fiber 5 into the element pair 4 enters the optical fiber 7 with the same optical axis. As illustrated in FIG. 6(b), when a voltage is applied between the electrode layers 9 and 10 from the drive power supply l1, the refractive index between the electro-optic elements 2 and 3 whose optical axes are in different directions changes. Therefore, the light emitted from the optical fibers 5 and 6 into the element pair 4 is refracted at the interface between the electro-optic elements 2.3 and enters the optical fibers 8 and 7, respectively.

Problems to be Solved by the Invention The above-mentioned optical deflection element l makes it possible to switch the optical transmission path by turning on and off the drive power supply 11 by utilizing the electro-optic effect, and the function of the optical information processing device (not shown) is improved. It can be used for parts, etc.

Here, the number of resolution points is one of the parameters that determines the performance of the optical deflection element l as described above.

This number of resolution points N is expressed by the deflection angle φ and the spread angle θ with respect to the optical axis of the beam destination, as N=φ/θ...■ The larger this number is, the better the performance of the optical deflection element l is. . Also, the spread angle θ of the beam light is determined by the wavelength λ of the beam light and the beam diameter ω, as follows: θ=ελ/ω ・・
・Represented as ■. Note that ε in the above equation is a constant that depends on the beam shape and intensity distribution and is approximated to 1. For example, if the beam shape is circular and the intensity distribution is suction, ε=1.22. As is obvious from the above formulas (■) and (■), in order to improve the number of resolution points N, it is necessary to decrease the spread angle θ of the beam light with respect to the deflection angle φ. The beam diameter ω may be expanded.

In other words, the number of resolution points N of the optical deflection element 1 having the structure as described above is
In order to improve this, it is necessary to increase the thickness of the element pair 4 to enlarge the beam diameter ω, but this would result in the refractive index between the electro-optical elements 2 and 3 being proportional to the applied voltage and inversely proportional to the distance between the electrodes. Therefore, in order to secure the necessary deflection angle, it becomes necessary to increase the capacity of the drive power source l1, which is not practical.

Means for Solving the Problem A thin film layer consisting of an electrode layer and an insulating layer is formed on opposing outer surfaces of a flat electro-optic layer, each of which is adjacent to the other through an edge inclined with respect to the optical axis of the incident light. A plurality of unit base materials are integrally laminated in the film thickness direction, and a driving power source for applying a voltage to the electro-optic layer is connected to the electrode layer.

Unit substrates each having a thin film layer formed of an electrode layer and an insulating layer adjacent to each other via edges inclined with respect to the optical axis of incident light are provided on opposing outer surfaces of the electro-optical layer in the form of a plate. , by integrally laminating multiple unit substrates in the film thickness direction and connecting a driving power source that applies voltage to the electro-optic layer to the electrode layer, the voltage is proportional to the applied voltage and inversely proportional to the distance between the electrodes. Since the refractive index of the electro-optic layer increases, a larger deflection angle can be obtained compared to the applied voltage, and the number of resolution points can also be improved by increasing the thickness of the device and expanding the beam diameter.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 to 4. Note that the same parts as in the conventional example described above are given the same names and numerals, and explanations thereof will be omitted. First, the optical deflection element l2 of this embodiment is a plurality of unit base materials 13 that function in the same way as the optical deflection element 1 described above and are laminated in the film thickness direction. Electrode layers l5 and #l! are adjacent to each other on opposing outer surfaces of the electro-optic layer 14, which is an electro-optical element, through edges inclined with respect to the optical axis of incident light. It has a structure in which thin film layers 17 each consisting of an edge layer 16 are formed. In this optical deflection element 12, a drive power source (not shown) is connected to the electrode layers 15 facing each other via the electro-optic layer l4.

Further, as illustrated in FIG. 3 etc., the thin film layer 17 of each unit base material 13 is integrated between the electro-optic layers 14,
The optical axis directions of the electro-optic layers l4 are alternately opposite.

In such a configuration, this optical deflection element 12
As illustrated in the figure, when the driving power source is off, the electrode layer 15
When no voltage is applied to the electro-optic layer 14, the refractive index of the electro-optic layer 14 is uniform, so that the light incident on the optical deflection element l2 travels straight inside.

Next, when the driving power source is turned on and a voltage is applied between the electrode layer l5 and each electro-optic layer 14, each electro-optic layer l4 is connected to the portion located between the electrode layers 15 and the insulating layer due to the electro-optic effect. The refractive index will be different between the portion located between 16 and 16, and the light incident on the optical deflection element 12 will be refracted at this boundary.

Note that this optical deflection element l2 is made of a unit base l as described above.
The thin film layers 17 between the three electro-optic layers 17 are integrated, and the direction of current flow to each electro-optic layer 14 is alternately reversed. However, since the optical axes of these electro-optical layers 14 are also alternately oriented in opposite directions, the refraction direction of the transmitted light is the same. It is.

In other words, the optical deflection element l2 can switch the optical transmission path by turning on and off the driving power supply, and can be used as a functional component of an optical information processing device (not shown).

Therefore, the effect of the optical deflection element l2 with the above-mentioned structure was changed using a transparent thin M of IT○ (indium-thin-oxide).
An electrode layer 15 made of an electrode, an insulating layer 16 made of a thin film of Sio, and a LiNbO. An example will be explained in which m unit base materials 13 each made of an electro-optic layer 14 are laminated.

First, as illustrated in FIG. 3, the thickness of each electro-optic layer l4 is d and the applied voltage is V. In this case, if the refractive index in the thin film stacking direction is ne and the electro-optic coefficient is rss, then the amount of change Δn in the refractive index of the electro-optic layer 14 is 2d. Here, this optical deflection element l2 is an electro-optic layer l2.
Since the thickness of the thin film layer 17 is extremely thin compared to the thickness of the electro-optic layer 14, the thickness of each electro-optic layer 14 is approximately D/m, assuming that the total thickness is D. Therefore, the above formula (■) becomes 2D.

Here, it is obvious that the amount of change Δn in the refractive index of the conventional device corresponds to the case where the constant m in the above equation (2) is set to 1. In other words, in this optical deflection element 12, the amount of change Δn in the refractive index is approximately m times that of the conventional device, and a large deflection angle can be obtained compared to the applied voltage.

Therefore, this optical deflection element 12 can easily improve the number of resolution points N by increasing the overall thickness D and expanding the beam diameter ω, and can provide high-performance light with low power consumption and a large deflection angle. A deflection element l2 can be obtained.

Note that the optical deflection element l2 having the above-described structure can be easily manufactured using existing thin film techniques such as sputtering, metal vapor deposition, and photoetching.

Furthermore, the materials used for each layer of the optical deflection element 12 of the present invention are not limited to those in this embodiment. For example, a material that produces a secondary electro-optic effect such as PLZT may be used as the electro-optic layer l4. It is also possible to adopt

Effects of the Invention As described above, the present invention provides a thin film layer consisting of an electrode layer and an insulating layer that are adjacent to each other through edges inclined with respect to the optical axis of incident light on opposing outer surfaces of a flat electro-optic layer. By providing unit base materials each having a shape of The refractive index of the electro-optic layer, which is inversely proportional to the distance between the electrodes, increases in proportion to the distance between the electrodes, so it is possible to obtain a large deflection angle compared to the applied voltage, and the beam diameter can be expanded by increasing the thickness of the device. By doing so, the number of resolution points can be improved, and a high-performance optical deflection element with low power consumption and a large deflection angle can be obtained.

[Brief explanation of the drawing]

1 to 3 are perspective views showing an embodiment of the present invention, FIG. 4 is a plan view, FIG. 5 is a perspective view showing a conventional example, and FIG. 6 is a plan view. l2... Light deflection element, l3... Unit base material, l4...
・Electro-optical layer, l 5 ・Electrode layer, ■ 6... Insulating layer, l 7... Thin film layer Applicant Noko Co., Ltd. 3U Figure

Claims (1)

[Claims] A plurality of unit substrates each having a thin film layer formed of an electrode layer and an insulating layer adjacent to each other via edges inclined with respect to the optical axis of incident light are provided on opposing outer surfaces of a flat electro-optic layer, and a plurality of unit substrates are provided. An optical deflection element, characterized in that the unit substrates are integrally laminated in the film thickness direction, and a driving power source for applying a voltage to the electro-optic layer is connected to the electrode layer.