JPS6284620A - optical logic element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an optical logic element that performs logical operations using optical signals, and particularly to an optical logic element that uses one of the optical signals as a control signal to switch between an AND circuit and an OR circuit function. , relates to an optical logic element with a small element length.

[Background of the invention]

As is well known, the basic operations that form the basis of current electronic computers are two-variable binary logical operations, and two-variable binary logical operations are based on the values (0, 1) of two input signals a and b. On the other hand, this is an operation that outputs 16 types of results as shown in the truth table of FIG. These logical operations are the basis for executing more complex logic, and these are the basic logical operations: AND.

All complex logical operations can be performed using the three operations OR and NOT. Therefore, in order to perform optical logical operations using optical signals and construct an optical computer, it is essential to realize an optical logic element that can perform these logical operations. However, conventional optical logic elements, as described in Japanese Patent Application Laid-Open No. 59-36230,
It is configured to combine one light emitting element and an optical switch to obtain logical outputs of Ex-NOR and EX-OR based on two electrical signals, and is based on AN, which is the basis of the above logical operation.
No consideration was given to a method of obtaining logical outputs of D and OR using elements having the same configuration.

[Purpose of the invention]

The present invention provides an optical logic element with a simple configuration that uses an optical signal from one light emitting element as control light to form an AND circuit or an OR circuit using an optical switch having two output terminals and two light emitting elements. The purpose is to

[Summary of the invention]

The optical logic element according to the present invention has two input ends and two output ends, and changes the refractive index of the two waveguide intersections according to the applied signal to the light incident from at least one input end. By providing an optical switch that outputs the light by switching to one of the output terminals and two light emitting elements respectively coupled to the two input terminals, it is possible to create an AND circuit or an OR circuit.
It consists of a circuit. That is, to explain using the diagram shown in FIG. 4 showing the basic concept, when the optical switch 3 is OFF
In this state, the light that has entered the optical waveguide 6 from the light emitting element 1 is outputted to the output end 5 via the optical waveguide 9, and the light that has entered the optical waveguide 7 from the light emitting element 2 is outputted to the output end 4 via the optical waveguide 8. shall be taken as a thing. When the optical switch 3 is in the ON state, the light that has entered the optical waveguide 6 from the light emitting element 1 is outputted to the output end 4 via the optical waveguide 8, and is input from the light emitting element 2 to the optical waveguide 7, contrary to the above. The light is transmitted through the optical waveguide 9 to the output end 5.
emitted to. Further, light emitting elements l and 2 are connected to Ll and L.
1 when the optical switch 3 represented by S is in the ON state.
．． Write the truth table (and The result will be as shown in Figures 5 and 6.Ll is OFF
When Ll is in the ON state, the AND logic output of the logic signals led to Ll and S is obtained from Pl, and when Ll is in the ON state, it is obtained from the OR logical ratio output of the logic signals led to Ll and S. It turns out.

[Embodiments of the invention]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of an optical logic element according to the present invention, and FIG. 2 is a sectional view taken along the broken line shown in FIG. 1. As shown in FIG. 1, in this embodiment, an X-type 2×2 reflective optical switch 11 and distributed feedback lasers 1 and 2 are
It was fabricated by monolithically integrating it on a semi-insulating InP substrate 10. After the grating 12 was formed on the substrate 10, crystal growth of the active layer 13 and guide layer 14 made of InGaAsP and the InP layer 15 was performed by the LPE method. Thereafter, the multilayer crystal layers other than the laser section 1.2 are removed by etching, and an optical switch 11 is formed in which the InGaAsP layer serves as an optical waveguide 16 and the InP layer serves as a cap layer 17.
Multilayer film crystal growth was performed using the LPE method. Next, the laser section 1.2, the optical switch 11 and the optical equal wave path 6.7.
8. After selectively etching areas other than 9, In
InP, which has a lower refractive index than GaAsP, was crystal-grown in a region excluding the optical waveguide to fabricate an optical logic element using a three-dimensional optical waveguide as shown in FIG. The optical switch 11 of the above embodiment is configured such that a current is passed through the reflective part of the optical switch 11 provided at the intersection of the optical waveguides 6.7.8.9, carriers are injected, and the current is turned on or off. The light passing through the optical waveguide is reflected or goes straight to perform a switching action.

In this embodiment, the intersection angle of the optical waveguides in the optical switch 11 (the angle formed by the optical waveguides 6 and 7 or 8 and 9) is 7°,
The width of the optical waveguide is 10 μm, and the distance between lasers 1 and 2 is 5 μm.
It was prepared with a diameter of 0 μm. The element size at this time is approximately 0.1+
++mXITfun. In the above example, the optical logic element was constructed using a carrier injection type reflective optical switch, but since the change in refractive index due to carrier injection is extremely large, it is also possible to further increase the intersection angle to reduce the element size. It is.

It goes without saying that any optical switch having a structure of two input ends and two output ends (for example, a directional coupler type optical switch) can be used as the optical switch of the present logic element.

〔Effect of the invention〕

As described above, the optical logic element according to the present invention has two input ends and two output ends, and directs light incident from at least one input end to either output end depending on the applied signal. Equipped with an optical switch that switches and emits light and two light emitting elements connected to two input terminals, it is compact with a length of less than 1 cm, and is also capable of implementing AND circuits and OR circuits, which are the basics of logical operations. Since an optical logic element having a circuit function can be obtained, optical logic operations and the configuration of an optical information processing system can be facilitated.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of an optical logic element according to the present invention, FIG. 2 is a cross-sectional view of the broken line shown in FIG. 1, and FIG. 3 is an operation output by a two-variable binary logic operation. FIG. 4 is a diagram showing the basic concept of the optical logic element, and FIGS. 5 and 6 are diagrams showing the operational truth table of the optical logic element. 1.2... Light emitting element 4.5... Output end 6, 7.8.9... Optical waveguide 11... Optical switch

Claims (4)

[Claims] (1) An optical switch having two input ends and two output ends, which switches the light incident from at least one input end to one of the output ends according to an applied signal and outputs the light; An optical logic element comprising two light emitting elements respectively coupled to two input ends. (2) The applied signal is an optical signal from one light emitting element, and is an AND or OR logical operation between the signal supplied to the other light emitting element and the signal supplied to the optical switch. An optical logic element according to claim 1, characterized in that: (3) The above-mentioned optical switch is a reflective optical switch that performs switching by changing the refractive index of at least a portion of the intersection of optical waveguides formed on a semiconductor substrate. The optical logic element described in item 1 or item 2. (4) The optical logic device according to any one of claims 1 to 3, wherein the light emitting device is monolithically integrated together with an optical switch on a semiconductor substrate.