JPS63200131A - Optical logic element - Google Patents

Abstract

PURPOSE:To electrically control a logic function by inserting an electrooptical effect layer having an electrode for applying the voltage within Fabry-Perot resonator contg. multiple quantum well. CONSTITUTION:The electrooptical effect layer 13 having the electrode for applying the voltage is inserted within the Fabry-Perot resonator contg. the multiple quantum well 15. Namely, a substance having the electrooptical effect changes refractive index depending on magnitude of the applied electric field. Therefore, the resonance wavelength of the substance having the electrooptical effect can be controlled depending on the voltage applied to said substance by inserting said substance within the Fabry-Perot resonator. Thus, even in case that the wavelength of a signal light is constant, the resonance characteristic of the Fabry-Perot resonator is changed by controlling the voltage, thereby obtaining the various kinds of the logic function.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical logic element, and particularly to an optical logic element in which the realized logic function can be electrically controlled.

[Conventional technology]

In recent years, there has been increasing interest in parallel, large-capacity information processing using light. In particular, digital optical information processing using digital signals can achieve high speeds and speeds that cannot be achieved with conventional electronic information processing.
It has the potential to perform parallel processing with high accuracy, and is being actively researched. Optical logic elements are necessary for digital optical information processing, and Jewell (J., L.
) et al. applied a Fabry-Perot resonator in which a multiple quantum well layer 15 is formed between dielectric multilayer films 16 and 19, that is, a multiple quantum well is included inside the resonator, as shown in FIG. Physics Letters (Applied)
Physics Letters) Volume 44, 172
(1984), it is inferior to controlling the signal light 2030 wavelength and the resonance wavelength of the Fabry-Perot resonator, and logic such as AND and NOR that outputs the output light 204 between the input lights 201 and 202. We showed that the function can be realized.

The principle of this element will be explained based on FIG.

Figure 3 shows the resonance characteristics of the Fabry-Perot resonator in Figure 2, where the vertical axis represents the transmittance and the horizontal axis represents the deviation from the resonance wavelength/full width at half maximum. is the resonance characteristic when the incident light intensity I is 0, the curve 301 is the resonance characteristic when the incident light intensity I is 1, and the curve 302 is the incident light intensity ■
310 shows an example of the position of the wavelength of the signal light. The intensity I of the incident light is 0.1.2
As the value changes, the exciton absorption of the multiple quantum well in the resonator becomes saturated and the refractive index changes, so the resonance characteristics of the Fabry-Perot resonator also change to 300.301.302.

For example, set the wavelength of the signal light to the order shown in Figure 3! 310, when the incident light intensity I is I=O, the transmittance is 1/2.1-1, the transmittance is 1/2. When I=2, the transmittance becomes 0. From this we can see that it works as a NAND. Various logical functions can be realized by changing the wavelength of the signal light. This relationship is shown in Table 1.

Table 1 [Problems to be Solved by the Invention] However, in the conventional optical logic elements described above, in order to select the logic function to be realized, the wavelength of the signal light or the resonant wavelength of the Fabry-Béro resonator must be need to change. This means that for each logic function, light sources with different wavelengths and elements with different dimensions are required.
The disadvantage is that the system configuration is complicated.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide an optical logic element in which the realized logic functions can be electrically controlled.

[Means for solving problems]

The optical logic device of the present invention includes a Fabry logic device including multiple quantum wells.
It is characterized in that an electro-optic effect layer having a voltage applying electrode is inserted inside the Perot resonator.

[Effect]

A substance with an electro-optic effect changes its refractive index depending on the magnitude of the electric field applied to it. For this reason, Fabry
When inserted into a Bero resonator, the resonant wavelength can be controlled by applying a voltage to a substance that has an electro-optic effect.In the present invention, even if the wavelength of the signal light is constant, the Fabry-Perot resonator can be The resonance characteristics of can be changed,
Various logical functions can be obtained.

〔Example〕

FIG. 1 is a sectional view of one embodiment of the optical logic element of the present invention. The structure of this optical logic element will be explained while describing the method of manufacturing it. An n-type A layer with a thickness of 1000 nm and an impurity concentration of lXl0"elf-' is formed on a Sn-doped n-type GaAs substrate 11.
j! N-type contact layer 12 made of As, undoped Aj! with a thickness of 1 μm! Electro-optic effect layer 13 made of As, p-type An! with a thickness of 1000 people! Impurity concentration consisting of As 5
A p-type contact layer 14 of
Barrier layer 15 consisting of o, hG a *, aA s
A multi-quantum well layer 15 in which 50 well layers 152 made of undoped GaAs with a thickness of 1 and 60 are laminated alternately.
form. The multiple quantum well layer 15 has a diameter of 20 μm.
It is removed by chemical etching, leaving only a portion intact. The surface of the multiple quantum well layer 15 is made of Ti0g and SiO□ and has a wavelength of 0.
．． It is coated with a dielectric multilayer film 16 having a reflectance of 96% for light of 8 μm to form an incident surface 17 . A p-type electrode 18 made of an A n /S n alloy is formed on the p-type contact layer 14 in the portion where the multiple quantum well layer 15 has been removed.
form. On the back surface of the substrate 11, a portion corresponding to the multiple quantum well layer 15 was removed by chemical etching into a circular shape with a diameter of 40 μm, and etched with TiOt and Sin.

The output surface 2 is coated with a dielectric multilayer film 19 consisting of
form 0. The reflectance of dielectric multilayer WA19 is at wavelength 0.
．． It is 96% for 8 μm of light. The dielectric multilayer film 19 on the back surface of the substrate 11 is removed, and an n-type electrode 21 of AuGeNi alloy is formed.

In the optical logic element having the above configuration, the entrance surface 1
Incident light 201, 202 and signal light 203 are incident on 7. The wavelength of the incident light 201 and 202 is the same as that of the multiple quantum well layer 15.
The wavelength is 820 nm, which is shorter than the peak wavelength of exciton absorption.

The wavelength of the signal light 203 is 850 nm, which is slightly longer than the peak wavelength of exciton absorption. The emitted light 204 emitted from the emitting surface has a wavelength of 850 nm.

The exciton absorption of the multiple quantum well layer 15 is saturated by the incident light 201 and 202, and the refractive index changes, so that the signal light 203 of the Fab S-Perot resonator formed between the dielectric multilayer films 16 and 19 is generated. The transmittance changes, and a logical operation is realized between the incident light 201 and 202 with the output light 204 as the output. At this time, when the voltage between the p-type electrode 18 and the n-type electrode 21 is changed from Ov to -1.6V, the refractive index of the electro-optic effect layer 13 increases by lXl0-'. Therefore, the resonant wavelength of the Fabry-Perot resonator shifts toward the long wavelength side by an amount equal to the full width at half maximum of the resonance curve. When the voltage between the p-type electrode 18 and the n-type electrode 21 is Ov, if the wavelength of the signal light 203 and the resonant wavelength of the Fapry-Perot resonator are made to match,
Voltage 10.8V, -1.6V, -2.4V,
By changing it to -3,6V, the signal light 203
The difference between the wavelength of

3/2.2, and various logic functions can be selected by voltage control while keeping the wavelength of the signal light 203 constant.

Although one embodiment of the present invention has been described above, the present invention is applicable to InP/I
It can be applied to any semiconductor material such as nGaAs.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to obtain an optical logic element whose logic function can be selected depending on the voltage.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a block diagram showing a conventional Fabry-Perot resonator, and Fig. 3 is a diagram for explaining the principle of the Fabry-Perot resonator shown in Fig. 2. FIG. 3 is a diagram showing resonance characteristics. 11... Substrate 12... N-type contact layer 13... Electro-optic effect layer 14... P-type contact layer 15... Multiple quantum well layer 151... ... Barrier layer 152 ... Well layers 16, 19 ... Dielectric multilayer film 17 ... Incident surface 18 ... P-type electrode 20 ... Output surface 21 ... ...N-type electrode 201,202 ...Incoming light 203 ...Signal light 204 ...Outgoing light

Claims (1)

[Claims] (1) An optical logic element characterized in that an electro-optic effect layer having a voltage applying electrode is inserted inside a Fabry-Perot resonator including a multiple quantum well.