JPS6070424A - Optical logical device - Google Patents

Abstract

PURPOSE:To obtain an optical logical device which can realize a logical operation by constituting a photoconductive substrate, a waveguide which is laminated on the substrate, has a smaller photoconductivity than that of the substrate and also has an electro-optical effect, and two polarizers placed on both end faces of the waveguide. CONSTITUTION:An input light A is converted to a linear polarized light through a polarizer 9 by an input waveguide 11, and led to a waveguide 2 of a fundamental element. An output light fetched through a polarizer 10 is fetched by an output waveguide 12. An input light B is made incident an a photoconductive substrate 1 by an input waveguide 13. When there is no input light B, the input light A does not appear in the output waveguide 12 due to the polarizers 9, 10. Also, even when the input light A does not exist and only the input light B exists, no light appears in the output waveguide 12. When the input light A exists and B exists simultaneously, the input light A becomes a linear polarized light whose plane of polarization has been varied by 90 deg. in the waveguide 2, and a light appears in the output waveguide 12. Only when the input light exists in both the input waveguides 11, 13, the output light appears, and operates as an AND device. In this way, all logical operations can be replaced with an optical logical operation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an optical logic device that performs logical operations using light.

(Background of the Invention) Recently, optical logic devices have attracted attention as new logic devices, and some of them have been put into practical use. New optical logic devices cannot construct an entire system unless they can implement the various logic operations AND, OR, NAND, NOR, NOT, flip-flop, and EXOR that have been realized with conventional electronic elements. This will be inconvenient.

Currently, for example, optical flip-flops using materials that have nonlinear transmission characteristics that depend on the intensity of transmitted light have been proposed, but they are far from being put to practical use.

(Object of the Invention) An object of the present invention is to provide a novel optical logic device that can realize each of the above-mentioned logical operations.

(Structure and operation of the invention) In order to achieve the above object, an optical logic device according to the present invention basically comprises a photoconductive substrate, which has a photoconductivity smaller than that of the substrate laminated between or on the substrates, and A waveguide with an electro-optic effect, and a power source that generates an electric field in the lamination direction of the substrate and the waveguide.

a basic unit formed from first and second polarizers disposed on both end faces of the waveguide; and a first unit that allows light to enter the waveguide via the first polarizer of the basic unit. an optical connection means, a second optical connection means for taking out the light outputted through the second polarizer, and a second optical connection means for taking out the light outputted through the second polarizer; and a third optical connection means that generates a conductive effect and an electro-optic effect in the waveguide, and the third optical connection means prevents light incident from the first optical connection means from reaching the second optical connection means. The first is controlled by light from the optical connection means.
Alternatively, it is configured to perform a logical operation on each light connected by the third optical connection means, or between both lights, and extract it from the second optical connection means.

AND, OR, NAND by the basic configuration or by combining a plurality of basic configurations.

Optical logic operations such as NOR and NOT flip-flops become possible.

(Description of Examples) Hereinafter, the present invention will be described in more detail with reference to the drawings and the like.

FIG. 1 is a schematic diagram showing a first embodiment of a basic element body for constructing an optical logic device of the present invention.

The thickness direction is exaggerated for ease of understanding. The photoconductive substrate l of the basic element main body 100 is B112S
The basic element body 100 is formed of a single crystal of i02o.
The thickness is approximately 0.5 mm.

Ga and Ca are diffused on the surface of a single crystal of B112Si02o to make the refractive index larger than that of the photoconductive substrate 1, and a portion 2 is formed in which the photoconductivity for blue light is suppressed to 1/1000 or less. .

This portion 2 has a thickness of several tens of μm and is used as a waveguide portion of the basic element main body 100. Hereinafter, this will be referred to as the waveguide 2 of the partial basic element main body 100.

A layered conductor 3 is formed on the surface of the waveguide 2 by vapor deposition. Conductivity - DC power supply 4 is connected between the substrate 1 and the conductor 3
Connect.

Linearly polarized input light 5 is input to the waveguide 2 while a voltage of 600 V is applied by this DC power source.

The control light 6 irradiates the basic element body 100 from the conductive substrate 1 side.

When the control light 6 is not present, the voltage is almost the same as that of the photoconductive substrate 1.
, and hardly reaches the waveguide 2, so that the electro-optical characteristics of that part are not changed.

As a result, the input light 5 is output without changing its polarization state.

When the control light 6 is applied here, the portion of the photoconductive substrate 1 having photoconductivity becomes low in resistance, and most of the voltage of the DC power source 4 is applied to the waveguide 2 portion.

The electro-optic characteristics of the waveguide 2 change, and the polarization state of the input light 5 is changed by the electro-optic effect while propagating through the element.

When the control light 6 is applied, the optical path length of the waveguide 2 and the voltage of the DC power supply 4 are determined by the electro-optic effect while the input light 5 propagates within the element. It is set so that it is in the direction of °.

Note that as the light source of the control light, B l 12 S I
O2.

It is necessary to use a single crystal that exhibits photoconductivity and contains ultraviolet to blue light. In this example, a Δr laser was used.

FIG. 2 is a schematic diagram showing another embodiment of the basic element body.

B i12 S i02 o single crystal photoconductive substrate 2
1, a single crystal of B112SiO2o doped with Ga and Ca is grown by a liquid phase epitaxial method to form a layered waveguide 22.

On this waveguide 22, N is grown by liquid phase epitaxial growth.
form 23. By connecting a DC power source 4 between the photoconductive substrate 21 and the layer 23, the basic element body 200 is formed.

The principle of operation of the basic element body 200 does not differ from that described in connection with FIG.

A basic element is constructed by arranging a polarizer at the input end face and output end face of each of the waveguides of these basic element bodies. Since the polarization direction of the polarizer varies depending on the application, it will be explained in connection with the embodiment of each optical logic device.

○AND Device FIG. 3 (I) schematically shows a logic device that performs an AND logical operation.

A basic element is used which is bonded to the input/output end face of the basic element main body 100 shown in FIG. 1 with the polarization directions of polarizers 9 and 10 perpendicular to each other.

The AND logical operation can be realized by one basic element in which optical connection means are arranged on the input end face of the basic element and on the photoconductive substrate 1, respectively.

Input light A is linearly polarized by the input waveguide 11 via the polarizer 9 and guided to the waveguide 2 of the basic element.

The output light extracted through the polarizer 10 is sent to the output waveguide 1.
2. Input light B is made incident on photoconductive substrate 1 through input waveguide 13 .

This AND device consists of a basic element having orthogonal polarizers 9 and 1o on the input and output end faces, and a waveguide if, which is an optical connection means.
It is composed of basic elements consisting of 12 and 13.

When there is no input light B, input light A does not appear in the output waveguide 12 because of the polarizers 9 and 1o.

Furthermore, even if there is no input light A and only input light B exists, of course no light will appear in the output waveguide]2.

Here, if input light A and B exist simultaneously, the input light A becomes linearly polarized light with a polarization plane changed by 90' within the waveguide 2, so that light appears in the output waveguide 12.

In this way, it can be seen that the output light appears only when there is input light in both input waveguides 11 and 13, and the device operates as an AND device.

FIG. 3(II) shows the device symbolically.

The AND device can also be realized by connecting two basic elements in series as shown in FIG. 3 (II[).

Both of the basic elements 30A and 30B have polarizers 9 and 10 orthogonal to each other on the input and output end faces.

A waveguide serving as an optical connection means is omitted.

The input light B is connected in the direction perpendicular to the waveguide of the basic element 30A, and the input light B is connected in the direction perpendicular to the waveguide of the basic element 30B.

Input light is connected to the input end face of the waveguide of the basic element 30A, and light from the output end face of the waveguide of the basic element 30A can reach the input end face of the waveguide of the basic element 30B via an external waveguide. It is arranged like this.

Basic element 3 when both input lights A and B exist
Output appears from 0B.

○OR device Figure 4 (I) shows a logical operation device that performs an OR logical operation.

The logical operation of OR can be realized with one basic element in which two waveguides are used as optical connection means for irradiating the photoconductive substrate.

Light is input to the waveguide 2 through the input waveguide 41 via the polarizer 9. The input waveguides 42 and 43 are arranged at positions where light can be incident on the photoconductive substrate 1.

When the four input waveguides 42 or 43 receive either or both of the input predecessors and B, the plane of polarization of the input light C from the input waveguide 41 is rotated by 90° within the waveguide 2.

As a result, an output appears in the output waveguide 12.

In other words, this device performs the logic/i5 calculation of A+B.

FIG. 4 (formerly symbolically showing the logic operation device).

0NOR Device FIG. 5 shows a logic operation device that performs NOR logic f7JW.

The logical operation of NOR can be realized using one basic element in which the optical connection means for irradiating the photoconductive substrate is two waveguides, and the polarization directions of a pair of polarizers are set in the same direction.

The polarization direction of the polarizer 9 on the input end face of the basic element is the same as the polarization direction of the polarizer 105 on the output end face.

Therefore, the input light A from the input waveguide 51, which is an optical connection means, and the input light B from the input waveguide 52 are connected to the photoconductive substrate 1.
Outgoing light appears in the output waveguide 12 only when both are absent.

Therefore, (A)X(B)=(A)+(B), and NO
It becomes an R device.

This logical operation is performed using the OR device described above and the NOT device described later.
Of course, this can also be achieved by combining devices.

0NAND Device FIG. 6 shows a logic operation device that performs NAND logic operations.

NAND devices use polarizers with matching polarization directions9.10
Basic elements 60A and 60B having the same shape and having the same shape are arranged and formed in parallel.

The input waveguide 61 is directed toward the photoconductive substrate 1 of the basic element 60A, and the input predecessor is connected thereto. Further, the input waveguide 62 is directed toward the photoconductive substrate 1 of the basic element 60B, and the input light B is connected thereto. The tips are branched and each tip has a basic element 6.
The input light C is transmitted through the waveguide 65 corresponding to the polarizer 9 at the input end face of the waveguide 2 of 0A and the polarizer 9 at the input end face of the waveguide 2 of the other basic element 60B. Connect to 12. The waveguide 66 is branched, and each tip is connected to a polarizer 105 at the output end face of the waveguide 2 to the basic element 60 and a polarizer 105 at the output end face of the waveguide 2 to the other basic element 60B. The output light is collected by this waveguide 66.

When either input light A or input light B is absent,
Alternatively, an output appears in the output waveguide 66 when neither exists.

In other words, (A > + (B) = (Δ)X (B), and NA
It becomes ND operation.

Moreover, this logical operation can of course be realized by a combination of the above-mentioned AND device and the below-mentioned NOT device.

○NOT Device As shown in FIG. 7, a basic element 70 is used in which polarizers 9 and 105 having the same polarization direction are arranged on the input and output end faces of the basic element.

The input waveguide 71 connects the polarizer 9 at the input and output end faces of the basic element.
Light is connected to the waveguide 2 via. The photoconductive substrate 1 of the basic element 70 is irradiated with signal light A via the input waveguide 72 .

When the signal light A exists, no output appears in the output waveguide 75, and when the signal light A does not exist, the output appears in the output waveguide 75. In other words, a logical operation of NOT is performed.

0RS Flip-Flop FIG. 8 shows an embodiment of a device that functions as an R-S flip-flop.

As shown in FIG. 8, elements 80A and 80B having polarizers 9 and 105 arranged on the input and output end faces of the basic elements are arranged in parallel.

The basic element, the DC power supply, is omitted.

Signal light A can be connected to the waveguide 2 of the element 80A via the input waveguide 81, and signal light B can be connected to the waveguide 2 of the element 80B via the input waveguide 82.

A reset signal light R1 is connected to the photoconductive substrate of the basic element 80A by a waveguide 83, and a set signal light S is connected to the photoconductive substrate of the basic element 80B by an input waveguide 84.

A waveguide 85 is connected to the output end face of the basic element 80A, and a portion thereof is branched into a waveguide 87, which is connected so as to be able to irradiate the photoconductive substrate of the basic element 80B.

Similarly, a waveguide 86 is connected to the output end face of the element 80B, and a portion thereof is branched into a waveguide 88, which is connected so as to be able to irradiate the photoconductive substrate of the basic element 80A.

The signal lights A and B are constantly sent into the waveguide via the waveguide 8L82.

When control light R is input (R=1,5=0), element 80
A is in the OFF state (no output light), and Q=O.

At this time, the element 80B remains in the ON state (state with output light). Since the branch signal of i is equal to 1, the element 80
A is locked in the OFF state. Element 80B remains in the ON state.

When the control light S is input (S=1.R=0), the element 80
B is in the OFF state, and i=0, which is suspicious.

At this time, the element 80A returns to ON from R-0, ζ-0. Since Q = "1, the element 80B is locked in the OFF state by the Q branch signal.

When both R and S are 0, the original state is maintained without changing any of the states described above.

"1" for both R and S is a prohibited state.

The above is summarized as Attached Table 1 at the end of the Detailed Description of the Invention column.

That is, this device operates as an RS flip-flop.

○Exclusive OR FIG. 9 shows an embodiment of a circuit that performs exclusive OR logical operation.

Elements 91 and 94 are elements that perform the NOR operation described above, and elements 92 and 93 are elements that perform the AND operation described above. Input/output waveguides, power supplies, etc. are omitted from illustration. The dashed arrow indicates that light is constantly supplied from that part.

The operation of the apparatus of this embodiment is summarized as Attached Table 2 at the end of the Detailed Description of the Invention column.

That is, this device operates as an exclusive OR.

Various modifications can be made to the embodiments described above within the scope of the present invention.

By using three or more waveguides as the optical connection means for connecting light to the photoconductive substrate, it is possible to perform logical operations on more inputs.

(Description of Effects) As described above, according to the present invention, various logical operations can be performed by combining one basic element or two identical basic elements, and all conventional logical operations can be performed using optical logic. -This optical logic device allows logical operations required for devices that use light itself as a signal or signal medium, such as optical memories, optical computers, and optical repeaters, to omit the photoelectric conversion process. It is possible to directly perform this method, and a wide range of applications can be expected.

According to the present invention, optical logic operations can be performed using a combination of the same or substantially the same basic elements, and since these basic elements are small, the basic elements can be integrated on a large scale, making it possible to perform more complex operations. logical operations are now possible.

Attached table 2

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a first embodiment of a basic element body included in a basic element used in an optical logic device according to the present invention. FIG. 2 is a schematic diagram showing a second embodiment of the basic element main body. FIG. 3 is a diagram showing a first embodiment of an optical logic device that performs an AND logical operation according to the present invention, its symbol representation, and a second embodiment. FIG. 4 is a diagram showing an embodiment of an optical logic device that performs an OR logical operation according to the present invention, and its symbol representation. FIG. 5 is a diagram showing an embodiment of an optical logic device that performs N0R(7) logic operations according to the present invention and its symbol representation. FIG. 6 is a diagram showing an embodiment of an optical logic device that performs a NAND logical operation according to the present invention and its symbol representation. FIG. 7 is a diagram showing an embodiment of an optical logic device that performs a NOT logic operation according to the present invention. FIG. 8 is a diagram showing an embodiment of an optical logic device that performs logical operations on an RS flip-flop according to the present invention. FIG. 9 is a diagram showing an embodiment of an optical logic device that performs an EXOR logical operation according to the present invention. 1.21.23...Photoconductive substrate 2.22...Waveguide 4...DC power supply 9.10.
105...Polarizers 60A, 60B, 70. ．． 80A, 80B, 91-94
...Basic elements 11.12.41.42.43.51.52, 53.6
1,62,65.6'6.7'1.72.7581~8
8... External waveguide patent applicant Hamamatsu Botonics Co., Ltd. agent Patent attorney Hisashi Inoro Figure 8 Figure 9

Claims (1)

[Scope of Claims] (J) A photoconductive substrate, a waveguide having less photoconductivity than the substrate and having an electro-optic effect, which is laminated between the substrates or on the substrate; A basic element formed from a power source that generates an electric field, first and second polarizers arranged on both end faces of the waveguide, and a basic element that supplies light to the waveguide via the first polarizer of the basic element. a first optical connection means for making the light incident thereon; a second optical connection means for taking out the light outputted through the second polarizer; a third optical connection means that generates a photoconductive effect on the substrate and an electro-optic effect on the waveguide; Each light connected by the first or third optical connection means is controlled by the light from the third optical connection means, or a logical operation is performed between the two lights to connect the light to the second optical connection means. Optical logic device configured to eject. (2) The photoconductive substrate is B i 12 S 1020
The waveguide is made of a single crystal of Ga on the surface of the crystal. 2. The optical logic device according to claim 1, wherein Ca is diffused to have a higher refractive index and lower photoconductivity than the crystalline portion. (3) The optical logic device according to claim 1, wherein the polarization directions of the first and second polarizers are orthogonal to each other or are in the same direction. (4) The third optical connection means is formed from a plurality of independent input waveguides, and the result of a logical operation between the lights connected by each input waveguide is taken out from the second optical connection means. The optical logic device according to scope 1. (5) a photoconductive substrate, a waveguide having a lower photoconductivity than the substrate laminated between the substrates or on the substrate and having an electro-optic effect, a power source that generates an electric field in the lamination direction of the substrate and the waveguide; A first optical connection means for inputting light into the waveguide via the first polarizer is connected to a basic element formed from first and second polarizers arranged on both end surfaces of the waveguide. A second optical connection means for extracting the light outputted through the second polarizer is connected, and the photoconductive substrate of the basic element is irradiated to produce the photoconductive effect and the photoconductive effect on the photoconductive substrate. first and second basic elements connected to a third optical connection means consisting of two independent waveguides that generate an electro-optic effect in the waveguide; A signal light is connected to one of the waveguides of the first optical connection means and the third optical connection means, and each second optical connection means is branched, and one of the branches is connected to an output terminal, and the other of the branches is connected to an output terminal. An optical logic device configured by connecting to the other waveguide of the third connection means of another basic element. (6) Lightning light is connected to the first and second optical connection terminals of the first basic element, and the third optical connection terminal of the first basic element is connected to the first and second optical connection terminals.
A light having a cent meaning is connected to one waveguide of the optical connection means of the second basic element, and a light having a cent meaning is connected to one waveguide of the third optical connection means of the second basic element. ,
6. The logic device of claim 5, wherein said logic device functions as a set/reset flip-flop.