JPS62215932A - Method and device for optical operation - Google Patents

Abstract

PURPOSE:To execute logical operation at a variable speed by executing in parallel an optical operation, by making plural coherent plane waves interfere by varying a phase in accordance with a signal, converting photoelectrically an interference pattern intensity and binary-coding it. CONSTITUTION:A coherent light beam by a laser 1 and a lens 2 is divided into two by a half mirror 3, reflected by mirrors of mirror arrays 4, 5 provided with piezoelectric elements driven by driving devices 7, 8, respectively, and goes to a coherent plane wave whose phase is varied in accordance with a signal. These reflected plane waves interfere, and an intensity of an interference pattern corresponding to an optical logical operation is observed and converted photoelectrically by a detector array 6 in which an observing position of each element is controlled by a position control device 10, processed by a threshold level corresponding to logic, and a binary digital value of a result of a parallel logical operation is outputted from an A/D converter 9. By such parallel optical operation, logical operation is executed at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for performing logical operations in parallel and at high speed using light.

[Prior art and its problems]

Research is progressing on computers that can perform calculations at high speed in order to process large-scale information, but methods that use sequential processing using electrical circuits are already approaching their performance limits. Therefore, supercomputers, array processors, etc.
Research is progressing on parallel processing architectures that execute multiple operations simultaneously. On the other hand, light has spatial expansion and its physical properties do not interfere with each other, so operations using light have excellent parallelism. Possible means for modulating light include three amplitudes, three phases, two frequencies, and polarization, and spatial light modulators are being developed.

However, most conventional spatial light modulators use liquid crystals, etc., and their response speed and number of parallels are insufficient.
It was unsuitable for high-speed calculations.

(Object of the Invention) An object of the present invention is to provide an optical operation method and apparatus for rapidly changing the phase of light and executing logical operations in parallel and at high speed.

[Means for solving problems]

The optical calculation method of the present invention causes a plurality of coherent plane waves to interfere, and makes the phase of each of the plurality of plane waves correspond to a change in an input signal, so that a portion of π/2 in the optical axis direction within the plane is
Alternatively, the intensity of the interference pattern is changed by modulating by π, and the position where the phase of each of the plane waves is changed and the position where the intensity of the interference pattern is observed are changed in the optical axis direction, and the intensity of the interference pattern is By photoelectrically converting the signal and changing the threshold value for binarizing the signal, a logical operation is performed that takes the phase modulation of the plurality of plane waves as input and outputs the binarized signal of the interference pattern. It is characterized by being executed spatially in parallel.

The optical calculation device of the present invention includes a laser, a collimating lens for collimating the laser beam from the laser, a beam splinter for dividing the laser beam into a plurality of beams, and a plurality of beam splinters for reflecting the plurality of divided laser beams. a plurality of laser beam reflecting means made up of minute mirrors; a plurality of phase modulation means made up of a number of minute piezoelectric elements that change the phase of the laser beam; and a plurality of phase modulation means that drive the phase modulation means. a driving device, a combining means for combining a plurality of laser beams modulated by the phase modulating means and the laser beam reflecting means, and an optical observation means for observing the intensity of an interference pattern of the combined laser beams. and a position control device that controls the position of the light observation means, and a digital conversion device that binarizes the signal obtained by the light observation means.

[Principle of the invention]

Coherent light is expanded and collimated, divided into two light beams to form an interferometer, and logical operations can be performed using interference fringe patterns that change by changing the phase of each of the two light beams in accordance with input data. Here, consider a Michelson type interferometer as shown in FIG. This interferometer includes a laser 105, a lens 106 that collimates the light from the laser, and a half mirror 10 that divides the collimated light into two.
3, and a mirror 101 that reflects the divided light, respectively.
102. Note that 104 in the figure is an observation surface for observing the intensity of the interference pattern.

The distance from half mirror 103 to mirror 101 is Ll
, the distance from the half mirror 103 to the mirror 102 is L
2. Let L3 be the distance from the half mirror 103 to the observation surface 104. The wavelength of the light emitted from the laser 105 is λ
,j! , m, and n are positive integers, for example, LI=l'
In the case of πλ, L2=2mπλ, as shown in FIG.
The plane waves from 2 have the same phase (b), and their interference pattern is represented by (C). If this interference pattern is observed at the position L3=2nπλ, the amplitude intensity L t, 3
If observed at a position of = (2nπ+π/2)λ, an amplitude intensity of 2 can be obtained. Next, when the distance L1 is increased by π/4, the phase (a) of the plane wave from the mirror lot is delayed by π/2, as shown in FIG. The interference pattern at this time is (c
), L3'-2nπλ and L3-(
The amplitude intensity becomes 1.5 at the position of 2nπ+π/2)λ. Thus, the distance, , L2.

Changing L3 changes the intensity of the interference pattern. At this time, logical operations can be performed by changing the distance Ll + L2 in accordance with the input data and binarizing the intensity of the interference pattern using an appropriate threshold.

Table 1 shows changes in the intensity of the interference pattern with respect to changes in Ll and L2.

In Table 1, (a) shows the intensity of the interference pattern with respect to changes in distance L1 and L2 when observed at the position L, +=2nπλ, (b), (C)
, (d) defines L3 as π/2°π and 3π/2, respectively.
This is a case where it is changed.

In the example shown in Figure 3, L+=21πλ, L2=2mπλ
Therefore, Table 1 (a), (b), (c), (d)
3(c)
As shown in , the distance L3 is changed from 2nπλ to πλ/
As the intensity of the interference pattern increases by 2, the intensity of the interference pattern increases by 1-2-
Changes to 1-0.

Similarly, in the case of Figure 4, Table 1 (a) and (b).

(C), corresponds to the second position from the top on the left side of (d), and as L3 changes, the interference pattern intensity is 1.5-1
．． It changes as 5-0.5-0.5.

For example, LI=21πλ shown in FIG. 5(a).

For the example of L2 = 2mπλ, the interference pattern intensity is digitized with a threshold of 1.25, and 1.25 or more is digitized with a threshold of 1.25.
If 5 or less is O, then L3”2nπλ, L3=(2nπ
+π)λ, L3 = (2nπ+3π/2)O at λ, L3 = (2nπ+-yr/2)l at λ
becomes. Input A corresponds to distance MLI, input B corresponds to distance L2, and input A and input B are O in the case of FIG.

Next, if input A is set to 1, ff1w1L+ wo21
yt A color (21π+π/2) When λ is changed, the pattern shown in FIG. 7 is obtained. Also, when input B is set to 1, the distance @ L 2 is changed from 2mπλ to (2mπ+π/2
), the pattern shown in FIG. 6 is obtained. FIG. 8 shows a pattern when input A and input B are set to 1 at the same time. At this time, when observed at the position of L3 = 2nπλ,
The output is as shown in the upper part of Table 2 for inputs A and B, and logic B can be realized.

Similarly to Table 2, the distance L3 is set to π/2. By varying π and 3π/2, logical operations of λ-, 0, and AND can be performed.

With distance %ll L + and L2 as biases, ΔL1. From the position where ΔL2 is changed, 14 types of logical operations can be executed as shown in Table 3 by changing π/4 or π/2 for a change of inputs A and B from O to 1. To shift the optical path length by ΔL, specifically, the position of the mirror may be changed by ΔL/2.

In order to perform this calculation in parallel, a mirror array is constructed by arranging a large number of mirrors whose positions in the vertical direction with respect to the optical axis can be independently changed. The observation plane is formed by a two-dimensional detector array, or a uniform scattering plane is placed to observe the scattering intensity of the interference pattern. For example, if the mirror is made of piezoelectric ceramic and an aluminum film coated on it, one calculation can be performed at a speed of more than 100 μs, and 1000 × 1000 elements of 100.17 m × 100 μm can be arranged in parallel. can be placed. If the calculation speed at this time is converted to a serial case, it is 10
It is 0 p seconds or more.

In addition, in the above explanation of the principle, in order to facilitate understanding, the case where two coherent plane waves are caused to interfere has been explained, but it goes without saying that the present invention can generally utilize the interference of a plurality of coherent plane waves.

〔Example〕

The present invention will be explained in detail below. FIG. 1 is a perspective view showing an embodiment of an optical calculation device that implements an example of the optical calculation method.

This optical calculation device includes a laser 1 that generates a laser beam, a collimating lens 2 that collimates the laser beam,
A half mirror 3 that acts as a beam splitter that divides the laser beam into two, and a laser beam reflecting means that is composed of a plurality of minute mirrors that reflect the two divided laser beams and change the phase of the laser beam. The laser beam is modulated by two mirror arrays 4 and 5 consisting of phase modulation means composed of a plurality of minute piezoelectric elements, two drive devices 7 and 8 that drive the phase modulation means, and the phase modulation means and laser beam reflection means. a detector array 6 which is an observation means for observing the two laser beams, a position control device 10 that determines the position of this detector array, and a detector array 6.
The A/D converter 9 is a digital conversion device that binarizes the signal obtained by the A/D converter 9. The light emitted from the laser 1 is collimated by a lens 2, then divided into two beams by a half mirror 3, and reflected by a mirror array 4 and a mirror array 5, respectively.

These mirror arrays 4.5 are composed of, for example, a large number of piezoelectric ceramics coated with an aluminum film. Electrodes are placed in a hollow ceramic,
When a voltage is applied, the surface of the ceramic changes due to its piezoelectric properties. This amount of change is about 50 nm/V. For example, if a laser with a wavelength of 1.5 μm is used, the phase can be changed by π/2 by changing the mirror position by 190 nm.

Therefore, by changing the voltage applied to the piezoelectric ceramic by 3.8 V, the phase can be changed by π/2. The input data that changes the mirror arrays 4 and 5 is composed of an amplifier that amplifies each input data to an applied voltage corresponding to the required amount of phase change, and a circuit that applies a bias voltage corresponding to the type of logical operation. Controlled by drives 7,8. The respective light beams reflected from the mirror array 4.5 are combined again by the half mirror 3 and interfere with each other on the surface of the detector array 6, such as a two-dimensional COD. By placing the detector array at a position determined by the type of logic operation using the position control device 10, a desired operation can be executed. The received light signal is binarized by the A/D converter 9 using a threshold value determined depending on the type of logical operation.

〔Effect of the invention〕

As described in detail above, logical operations can be executed in parallel and at high speed by using the optical operation method and optical operation device of the present invention.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an embodiment of the optical calculation device of the present invention, Fig. 2 is a diagram showing the principle of the optical calculation method, and Figs. 3 to 8 show the phases of plane waves and interference patterns. FIG. l...Laser 2...Lens 3.103...Half mirror 4,5...Mirror array 6...Detector array 7.8...Drive device 9...・・A/D converter 10・・・Phase control device 101, 102 ・・Mirror-104・
...Observation surface

Claims (2)

[Claims] (1) By causing a plurality of coherent plane waves to interfere with each other, and making the phase of each of the plane waves correspond to changes in the input signal, and partially modulating the plane by π/2 or π in the optical axis direction. The intensity of the interference pattern is changed, the position where the phase of each plane wave is changed and the position where the intensity of the interference pattern is observed are changed in the optical axis direction, and the intensity of the interference pattern is photoelectrically converted to generate a signal. By changing the threshold value for binarization, a logical operation is performed spatially in parallel, using the phase modulation of the plurality of plane waves as input and outputting the binarized signal of the interference pattern. An optical calculation method characterized by: (2) A laser, a collimating lens that collimates the laser beam from the laser, a beam splitter that divides the laser beam into multiple beams, and a large number of minute mirrors that reflect the divided laser beams. a plurality of laser beam reflection means configured, a plurality of phase modulation means constituted of a large number of minute piezoelectric elements that change the phase of the laser beam, a plurality of drive devices that drive the phase modulation means; a combining means for combining a plurality of laser beams modulated by the phase modulation means and the laser beam reflection means; a light observation means for observing the intensity of an interference pattern of the combined laser beams; An optical calculation device comprising: a position control device that controls a position; and a digital conversion device that binarizes a signal obtained by the optical observation means.