JPH0297922A - Light flip-flop - Google Patents

Abstract

PURPOSE:To simplify a constitution and the design of a circuit by providing an optical bistable element and an optical Stark effect element inside a laser resonator, inputting a set or reset signal light from an external part, controlling a laser generation and executing an F/F action. CONSTITUTION:In order to make the F/F into a set condition, a set signal light 7 of a wavelength lambda0 is inputted from the external side of a mirror 1 along an optical axis 8. When the magnitude of the signal light 7 is made into a prescribed magnitude, an OBSD (bistable device) 4 is made into a transparent condition, an input light to the OBSD 4 is totally transmitted, even a natural emitted light is transmitted, a feedback by a mirror 2 to a laser medium 3 is made into a sufficient quantity, the laser generation is executed, the laser light of the wavelength lambda0 is outputted as an output signal light 11 from a mirror 12, and the F/F is made into the set condition. Next, when the same light is inputted as the reset signal light to an SHG (second higher harmonics generating element) 9, the light of a wavelength lambda0/2 is inputted to an OSED (optical Stark effect element) 5, the laser light in the middle of generation is interrupted, and the F/F is reset.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical flip-flop, and particularly to an optical flip-flop capable of complete binary operation (hereinafter referred to as optical F/F).

[Conventional technology]

In recent years, ultrahigh-speed information processing technology has made remarkable progress in semiconductors, superconducting electronics, etc., based on advances in microfabrication technology. In addition, in optoelectronics centered on lasers, extremely short optical pulses of 6 fmtoseconds, which is close to the limit for light, are generated, which is much faster than the semiconductor and superconducting electronics technologies mentioned above. It is expected that large-capacity information processing will be possible. In particular, much attention has been focused on the development of optical computers that take advantage of the properties of light and are capable of much faster and completely parallel operations than current electronic computers. It is important that the optical logic element, which is the basis of this, operates at high speed in logical operations and information storage, and also requires conditions such as the possibility of two-dimensional or three-dimensional parallel processing, and the possibility of integration. Many optical crystals that exhibit nonlinear response with high efficiency under these conditions have been developed, and semiconductor optical logic devices using these have been proposed. It is expected that proposals for these new technologies will become more active in the future, and that optical information processing technology will be put into practical use.

Conventionally, for example, literature abstract physics letter (App
Lied Physics Letters 50,1
There is an optical F/F that utilizes an optical bistable device (hereinafter referred to as 0BSD) as shown in Japanese Patent No. 5,591,987). This optical F/F is composed of a photoactive layer and reflecting mirrors attached to both ends of the photoactive layer. By doing so, a semiconductor etalon is formed and optical bistable operation becomes possible.

FIG. 7 is an explanatory diagram showing an example of a conventional optical F/F. In the figure, the optical F/F is made of GaAs/A as the active layer 17.
It is composed of an lGaAs superlattice and reflecting mirrors 18 formed at both ends of this superlattice.

In Figure 6, the horizontal axis is the intensity of one input light, and the vertical axis is the intensity of the output light 20.
FIG. 2 is an explanatory diagram showing the input/output characteristics of 0BSD as the strength of 0BSD. In the figure, when the intensity Pi of the input light 19 is Pi<PL, the input light is absorbed by 0BSD, so the output light 20 is very small, but when Pi is gradually strengthened and Pi>P2, 0BSD becomes It becomes transparent, and the intensity of the output light 20 becomes the same as the intensity of the input light 19. Conversely, when the intensity of the input light 19 is gradually weakened, the transparent state is maintained until Pi=P1, but when Pi<PL, the input light 19 becomes 0B again.
It is absorbed by the SD, and the output light 20 becomes smaller.

Based on the above operation, by superimposing the signal light having the strength ph on the bias light while inputting the light having the strength pb as the bias light, the 0BSD becomes a transparent state and the bias light is transmitted. This state corresponds to the F/F set state. Next, by subtracting the light of intensity Pl from the bias light, 0BSD becomes an absorption state, and the transmitted light becomes very small.

This state corresponds to the reset state of the F/F.

As described above, the optical F/F is realized by repeating the transparent state and the absorption state depending on the intensity of input light.

[Problem to be solved by the invention]

The above-mentioned conventional optical F/F has a drawback that first, the signal light for resetting must be a bias light with reduced intensity. In other words, subtraction processing is required for light intensity, but no subtraction technique that can be easily applied to F/F has been proposed.

Second, it has the disadvantage of requiring bias light. That is, the level of the intensity of light input to the F/F is the level of bias light Pb, the level of set light (strong) ph,
Three levels of reset light level (weak) PI are required, which may complicate the design of a binary digital optical circuit and cause problems. Furthermore, since bias light is required, a light source is required in addition to the signal light for setting and resetting, making the configuration complicated, and furthermore, it is necessary to devise ways to prevent the reflected light of the bias light from becoming noise. There are also drawbacks.

An object of the present invention is to provide an optical flip 70 that uses the characteristics of laser light to improve the above-mentioned drawbacks.

[Means to solve the problem]

The optical flip-flop of the present invention has a first
and a second mirror, a laser medium placed in the optical resonator to cause laser oscillation, and an optical twin placed on the laser optical axis during laser oscillation in the optical resonator. a stabilizing element, an optical Stark effect element disposed inside the optical resonator, a pumping section that supplies energy to cause the laser medium to oscillate, and a pumping section that is perpendicular to the laser optical axis with respect to the optical Stark effect element. and a second harmonic generation element that causes a second harmonic having a wavelength of 1/2 of the input light to be incident as a control signal light in the direction.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, the optical F/F includes an optical resonator composed of first and second mirrors 1 and 2 with a reflectance R1≠1, and a laser placed inside this optical resonator for causing laser oscillation. A medium 3, an optical bistable device (OBSD) 4 placed on the laser optical axis 8 during laser oscillation inside the optical resonator, and an optical Stark effect element (hereinafter referred to as OBSD) also placed inside the optical resonator.
It's called SED. ) 5, and a pumping unit 6 that supplies energy to cause the laser medium 3 to oscillate.
and a second harmonic generation element (hereinafter referred to as SHG) that makes a second harmonic with a wavelength of 1/2 of the input light enter the 03ED 5 in a direction perpendicular to the laser optical axis 8 as a control signal light. )9. Note that the above 0BSD4, laser medium 3, 08ED5, SH
G 9 is arranged at an appropriate angle with respect to the direction in which the light travels so that the light reflected from each surface thereof does not interfere with the signal light.

FIG. 2 is a configuration diagram showing 0BSD 4, and FIG. 3 is its input/output characteristic diagram. In FIG. 0, the horizontal axis is the intensity of input light, and the vertical axis is the intensity of output light. The intensity of input light 13 is 0B
Since the light is absorbed internally when it is weaker than the threshold PT of SD4, the intensity of the output light 14 is weak, and the input light 1
When the intensity of 0BSD 3 exceeds PT, the 0BSD 4 becomes transparent, and the input light 13 becomes the output light 14 (the intensity of the output light at that time is the same as the intensity of the input light).

FIG. 4 is a configuration diagram showing the 0SED 5, and FIG. 5 is its input/output characteristic diagram. In FIG. 0, the horizontal axis is the wavelength λ of the input light, and the vertical axis is the intensity of the output light. In 03ED 5, the output light 16 with respect to the input light 15 (wavelength λO) exhibits two types of characteristics depending on the presence or absence of the control signal light 12 (wavelength λ0/2). First, when the control signal light 12 is incident, the 03ED 5 produces the Stark effect and exhibits A characteristics, that is, it absorbs the input light 15 of wavelength λ0. Conversely, when the control signal light 12 is not incident, the B characteristic is exhibited, and the input light 15 with the wavelength λO is transmitted. Note that the B characteristic in the same figure shows that the absorption wavelength of 08ED 5 is a wavelength λ1 that has no relation to the wavelength used by the optical F/F of the present invention.
This indicates that the data will be moved to .

The SHG 9 converts input light with wavelength λO into output light with wavelength λO/2.

In Fig. 1, the second mirror 2 of the optical resonator is the output mirror, and the state in which the laser beam is output from this as the output signal light 11 is the set state of the F/F, and the state in which the laser beam is not output. A state where there is no such state is a reset state. In the initial state of operation, the laser medium 3 is activated by the pumping section 6 and is ready for laser oscillation. At this time,
Spontaneous emission light with a wavelength of ^0 is generated from the laser medium 3, but when the intensity of this light is defined as Pdark, this spontaneous emission light is absorbed by the 0BSD 4, and the If sufficient feedback is provided by the mirror 2, no laser oscillation occurs (see FIG. 3), that is, the initial state is a reset state. In addition, 0SED5 in the initial state
indicates the B characteristic in FIG.

Next, in order to set this F/F, a set signal light 7 having a wavelength λ0 for setting the F/F is input from the outside of the first mirror 1 along the laser optical axis 8. If the size Pset of this set signal light 7 is the size shown in FIG. 3, 0BSD4 will be in a transparent state and 0BSD4 will be in a transparent state.
All input light to D4 is transmitted. Therefore, the spontaneous emission light is also transmitted, and a sufficient amount of feedback by the second mirror 2 to the laser medium 3 is generated, laser oscillation occurs, and the laser light with the wavelength λO is transmitted from the second mirror 2 to the output signal light 11.
is output as In this way, the F/F becomes set. If the intensity Pld of the laser light inside the optical resonator is sufficiently large (1), the laser continues to oscillate even if the input of the set signal light 7 is stopped in this state. Therefore, the F/F continues to maintain its set state.

Next, to put this F/F into the reset state, send the same light (wavelength λO) as the one used when setting the F/F to the reset signal light 1.
Enter SHG 9 as 0. At that time 5) IG 9
Light with wavelength λO/2 is generated from 0SED 5
The control signal light 12 becomes incident on the 03ED5. As a result, it exhibits characteristic A in FIG. 5, and does not transmit the laser beam of wavelength ^O during oscillation. Therefore, this time the feedback by the first mirror 1 is no longer sufficient, the laser oscillation is stopped, the output light from the second mirror 2 disappears, and the F/F is reset. At this time 0B
The intensity of the input light to SD4 is Pdark shown in Figure 3.
This is absorbed by the 0BSD 4 and returns to the initial reset state, so even if the input of the reset signal light 10 is stopped in this state, the reset state is maintained.

In this way, set signal light 7. An optical F/F can be realized by causing the laser to repeat oscillation and stop states using the reset signal light 10.

〔Effect of the invention〕

The optical F/F of the present invention has an 0BSD and an 0SED installed inside a laser resonator, and controls the laser oscillation by inputting a set signal light or a reset signal light to this from the outside, and operates the F/F. has been realized. Therefore, arithmetic processing such as subtraction processing for light intensity is unnecessary, and the configuration becomes simple.

Furthermore, since bias light is not required, no light source other than signal light is required. Therefore, there is no need to consider noise caused by bias light, and the design becomes easier. Furthermore, the F/F operation can be realized using only two values, ie, a state in which light is present and a state in which there is no light, as a signal light, and a great effect is obtained in that the design of an optical logic circuit is easy.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the present invention, Fig. 2 is a block diagram showing 0BSD, Fig. 3 is an input/output characteristic diagram of 0BSD, Fig. 4 is a block diagram showing 05ED, and Fig. 5 is a block diagram showing 0BSD. 08ED
6 is an input/output characteristic diagram of a conventional optical F/F, and FIG. 7 is a configuration diagram showing an example of a conventional optical F/F. 1.2...Mirror 3...Laser medium, 4...0
BSD, 5...0SED, 6...Pumping section, 9
...SHG.

Claims (1)

[Claims] an optical resonator composed of first and second mirrors with a reflectance not equal to 1; a laser medium placed within the optical resonator to cause laser oscillation; and a laser optical axis during laser oscillation within the optical resonator. an optical bistable element disposed above; an optical Stark effect element disposed inside the optical resonator; a pumping section that supplies energy to cause the laser medium to oscillate; A second harmonic having a wavelength of 1/2 of the input light is incident as a control signal light in a direction perpendicular to the laser optical axis.
An optical flip-flop comprising a harmonic generation element.