JPH03267922A - Optical switch array - Google Patents

Abstract

PURPOSE:To allow sure and high-speed optical switching by forming incident side reflecting mirrors and exit side reflecting mirrors respectively having electrode functions on both surfaces of a substrate and controlling the switching of the coupling between incident and exit side optical waveguides by utilizing the electrooptic effect of the substrate. CONSTITUTION:The transparent substrate 11 formed of a material having the electrooptical effect, for example, PLZT or liquid crystal is used as a base. The incident side reflecting mirrors 12 of single or plural layers which are disposed between the incident side optical waveguides 13 and have the electrode function are provided on one surface of this substrate 11 and the exit side reflecting mirrors 14 of single or plural layers which are provided with exit windows for the exit side optical waveguides 18 and have the electrode function are provided on the other surface. Voltage impressing means for impressing voltages selectively to these respective reflecting mirrors 12, 14 are provided. The electric field distribution in the substrate 11 is controlled by the selective voltage impression and the coupling between the incident and exit side optical waveguides 13 and 18 is switched and controlled by the electrooptic effect thereof. The sure and high-speed optical switching is possible in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical switch array used in fields such as optical communications, optical information processing, and optical switching.

Prior Art Conventionally, this type of optical switch was published in Japanese Patent Application Laid-Open No. 58-9061.
There is one shown in Publication No. 9. FIG. 4 shows its configuration, in which a pair of electrodes 2a and 2b for generating an electric field in the depth direction is provided on one surface of the electro-optic crystal 1, and one end surface perpendicular to the above-mentioned surface of the electro-optic crystal 1 is provided. and a plurality of optical fibers 3a, 3b.

3c, and concave reflecting mirrors 4a, 4b which exhibit a light condensing effect are provided on the other end faces facing each other, and each optical fiber 3a, 3
b, 3c are these concave reflecting mirrors 4a.

They are optically coupled via 4b. 5 is a SELFOC lens for collimation.

In such a configuration, a power source 6 is connected between the electrode pair 2a and 2b.
By applying a voltage, an electric field distribution is generated in the depth direction of the electro-optic crystal 1, and a refractive index distribution is formed inside due to the electro-optic effect.

Then, the light emitted from any of the optical fibers 38 to 3C into the electro-optic crystal 1 propagates inside while being refracted.

Therefore, by electrically controlling the refractive index distribution of the electro-optic crystal 1 and switching the incidence on the concave reflectors 4a and 4b, it is possible to switch the optical coupling between the input and output optical fibers 3a to 3C. be.

Problems to be Solved by the Invention However, since the electro-optic effect of an electro-optic crystal is generally small, in the case of the configuration shown in FIG. 4, there is a limit to the number of optical fibers that can be coupled. Further, the concave reflecting mirrors 4a and 4b must also be manufactured with high precision, resulting in high costs. Furthermore, since the electrode pairs 2a and 2b are formed parallel to the light propagation direction, it is difficult to integrate them into a one-dimensional or two-dimensional array, that is, to form an array. Another problem is that it is difficult to apply to laminated optical circuits because the input and output light propagation directions are opposite.

Means for Solving the Problem A substrate made of a substance having an electro-optic effect is provided, and on one surface of this substrate, a single unit having an electrode function is arranged between incident side optical waveguides arranged in a one-dimensional array. A layer or multiple layers of an input side reflecting mirror are provided, and a single layer or multiple layers of an output side reflecting mirror having an electrode function and having an output window for an output side optical waveguide corresponding to an input side optical waveguide is provided on the other surface. , and a voltage applying means for selectively applying a voltage to each of the incident side reflecting mirror and the exiting side reflecting mirror is provided, and the electric field distribution inside the substrate is changed by selectively applying a voltage between these reflecting mirrors. The coupling between the input and output optical waveguides can be switched and controlled using the electro-optic effect.

Since the substrate does not exhibit an electro-optic effect when the reflector functioning as a working electrode is set at equal potential, the incident light passes straight through the substrate and is coupled to the output-side optical waveguide of the corresponding output window. On the other hand, when a voltage is applied between a certain incident-side reflecting mirror and an exit-side reflecting mirror adjacent to a certain incident-side optical waveguide of interest, an electric field distribution is generated inside the substrate. As a result, the refractive index of this portion of the substrate changes due to the electro-optic effect and has a refractive index distribution, so that input light is refracted inside the substrate. The refracted light propagates while changing its course while repeating reflection a plurality of times between the output-side reflecting mirror and the input-side reflecting mirror, and is switched and coupled to another adjacent output-side optical waveguide.

This enables reliable and high-speed optical switching. Furthermore, since multiple reflections between reflecting mirrors are utilized, switching is possible even if the electro-optic effect is small, and low voltage driving is possible. Structurally, it is sufficient to form films of predetermined incident side and output side reflecting mirrors on both sides of the substrate, and in-plane batch processing is possible, making it possible to form small devices and arrays. Furthermore, since the propagation direction is the same from input to output, it is easy to apply to laminated optical circuits.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 3. The optical switch array of this embodiment is constructed based on a substrate 11 made of a material having an electro-optic effect, such as PLZT or liquid crystal, and transparent to the wavelength of light used. On the incident side surface of the substrate 11, a plurality of incident side reflecting mirrors 12 having an electrode function are individually formed in a single layer or multilayer structure. In this embodiment, the substrate 11 is P
LZT and the incident side reflecting mirror 12 are made of an Au metal film.

These incident-side reflecting mirrors 12 are one-dimensionally arranged at regular intervals so as to fill the space between the incident positions 2 of the incident-side optical waveguides arranged in a one-dimensional array at equal intervals, and here the incident-side optical fibers 13. There is. Further, on the other surface of the substrate 11 on the emission side, a film of an emission side reflecting mirror 14 having an electrode function is formed in a single layer or in a multi-layer structure. This embodiment has a two-layer structure consisting of a thin film transparent electrode 14a made of ITO and a metal film 14b made of Au. The metal film 14 of this output side reflecting mirror 14
In b, circular output windows 1 are arranged correctly in a one-dimensional array in correspondence with the input position P of the input side optical fiber 13.
5 is formed. The optical switch array of this embodiment, including such reflecting mirrors 12 and 14, can be formed easily and with high precision using ordinary thin film forming techniques such as sputtering and vapor deposition, and processing techniques such as photolithography and etching. It can be made.

Here, a voltage is selectively applied to each of the incident side reflecting mirrors 12 by a voltage applying means (not shown). The output-side reflecting mirror 14 acts as a common electrode, and is wire-connected to both of the input-side reflecting mirrors 12 so as to receive and receive voltage electrically independently. Further, the optical fiber 1
A collimating lens 16 is coupled to the incident position P of No. 3 as shown in FIG. It is something that will be done.

In such a configuration, the operating principle of this embodiment will be explained with reference to FIG. Now, consider the case where incident light 19a (linearly polarized light having a polarization plane in the array direction) propagating through a certain incident optical fiber 13a is collimated by collimating lens 16a and enters substrate 11.

At this time, if the incident side and output side reflecting mirrors 12 and 14 are set to have the same potential (in this case, they may be grounded), the incident light 19a passes straight through the substrate 11 as shown by the dashed line, and passes through the corresponding output window. The light passes through the condenser lens 17a of 15a and is emitted into the emitting optical fiber 18a as emitted light 20a. On the other hand, if a voltage V is applied to the input side reflector 12b adjacent to the input side optical fiber 13a, and the other input side reflector 12a and the output side reflector 14 remain grounded, then the input side reflector 12b
An electric field distribution as shown by the broken line is generated inside the substrate 11 corresponding to this. Thereby, the refractive index of the substrate 11 changes due to the electro-optic effect, and a refractive index distribution is formed. Therefore, the incident light 19a that has entered from the optical fiber 13a is refracted inside the substrate 11 as shown by the solid line, and is also reflected by the reflecting mirror 14,
12c, the light beam propagates through repeated reflections a plurality of times, is coupled to the condenser lens 17b of the adjacent output window 15b, and is emitted as output light 20b into the corresponding output side optical fiber lsb.

Therefore, in general terms, as shown in FIG. The output side optical fiber corresponding to the side optical fiber 13 is 18a, and the output side optical fibers on both sides thereof are 18a.
b, 18c, the output side optical fibers 18a to 18c are controlled by controlling the voltage application to the input side reflecting mirrors 12b and 12c.
18c. That is,
If no voltage is applied to either of the incident side reflecting mirrors 12b and 12c, the output side optical fiber 18a is coupled to the incident side reflecting mirror 1.
If voltage is applied only to 2c, it will be coupled to the output side optical fiber 18b, and if voltage is applied only to the input side reflector 12b, it will be coupled to the output side optical fiber 18c.

It should be noted that various modified configurations are possible, not limited to the illustrated example. For example, if the reflecting mirrors 12 and 14 have a dielectric multilayer structure, they will have a high reflectance without absorption.

Effects of the Invention As described above, the present invention forms an entrance-side reflecting mirror and an exit-side reflecting mirror each having an electrode function on both sides of a substrate made of a substance having an electro-optic effect, and selects a By applying a voltage to the substrate, the electro-optic effect of the substrate is used to switch and control the coupling between the input and output optical waveguides, making it possible to perform reliable and high-speed optical switching. Since multiple reflections are used, switching is possible even if the electro-optic effect is small, and low voltage driving is possible.Structurally, the films of the reflection mirrors on the incident and exit sides are placed on both sides of the substrate. It only needs to be formed, in-plane batch processing is possible, and miniaturization of devices and arrays is possible.In addition, since the propagation direction is the same from input to output,
Application to laminated optical circuits is also easy.

[Brief explanation of drawings]

Figures 1 to 3 show an embodiment of the present invention.
Fig. 1 is a schematic cross-sectional structural diagram showing the operating principle, Fig. 2 is a perspective view showing the structure of a single switch array, Fig. 3 is a perspective view for explaining the general principle of operation, and Fig. 4 is a conventional example. FIG. 11...Substrate, 12...Incidence side reflecting mirror, 13...
Incoming side optical waveguide, 14... Outgoing side reflecting mirror, 15...
Output window, 18...The output side optical waveguide is shown in the figure.

Claims (1)

[Claims] a substrate formed of a substance having an electro-optical effect;
A single-layer or multi-layer input-side reflecting mirror having an electrode function is disposed between the input-side optical waveguides arranged in a dimensional array and formed on one surface of the substrate, and an output mirror corresponding to the input-side optical waveguides. A single-layer or multi-layer output side reflector having an electrode function and provided with an output window for a side optical waveguide and having an electrode function formed on the other surface of the substrate, and each of the input side reflectors and the output side reflector. The electric field distribution inside the substrate is controlled by selectively applying a voltage between these reflecting mirrors, and the electro-optical effect is used to control the electric field distribution.
An optical switch array characterized in that coupling between output side optical waveguides is switched and controlled.