Optical Parallel Logic Research Articles

Experimental realisation of parallel optical logic gates and combinational logic using multiple beam interference

In this paper, we report the experimental realisation of parallel optical logic gates and some combinational logic using multiple beam interference in three cascaded Michelson type interferometers. Considering light intensity at different points of 2-D interference pattern of four input laser beams as output, (i) two input AND, OR, NAND, NOR, XOR, XNOR optical logic gates in parallel, (ii) three input AND and NAND optical logic gates in parallel, and (iii) four input AND logic gate as well as some combinational logic in parallel were realised. By controlling the four input laser beams electro-optically or all-optically using nonlinear optical materials having large nonlinearity and fast response time, ultrafast photonic information processing can be performed utilizing present scheme due to parallel operation of large number of logic gates.

Primitive Optical Computing Model with Films: Boolean Conjunction of the Square Matrix-Arrayed Color Codes

Color is one of the most useful and attractive characteristics of light applicable to optical science and the related industries. In recent decades, a number of studies focusing on the use of light as a key component of computation have attracted considerable attention from researchers and engineers because these studies are potentially applicable to signal processing through optical interconnections between electronic devices. Such studies include the optical parallel logic gates proposed by a Japanese research group, allowing spontaneous and parallel computing with spatial coding using lights, simply by overlaying a pair of shadowgram images. For computational handling of the colors visible to human eyes,Commission Internationale de l’Eclairgehas defined CIE 1976 color space (CIELAB). The author has been engaged in the development of CIELAB-based printable and computable color codes possibly used for novel optical logic gate system as one of natural computing approaches. In the present study, by employing the pairs of CIELAB-coded-printed transparent films overlaid, a Boolean operation for the crossing (conjugation) of 2-by-2 color matrices based on the scanning of CIELAB values was demonstrated. This approach is still primitive but might be a significant step for manifesting the array-based processing of colors representing print-preserved and digitalized information.

Parallel optical logic operations on reversible networks

A generic optical network architecture is proposed for the implementation of programmable logic operations. Based on reversible optical gate elements the processor is highly energy efficient and intrinsically fast. In this architecture the whole logic operation is executed by light propagating through the system with no energy dissipation. Energy must be spent only at the input interface and at discrete locations where the logic operation results are to be detected. As a consequence, the theoretical lower limit for energy dissipation in logic operations must be reconsidered. The strength of this approach is demonstrated by examples showing the implementation of various lossless logic operations, including Half Adder and Full Adder.

Theoretical Study in the Realization of Real-Time Parallel Optical Logic Operations Using Two-Wave Mixing in Photorefractive Materials

Theoretical Study in the Realization of Real-Time Parallel Optical Logic Operations Using Two-Wave Mixing in Photorefractive Materials

Parallel optical logic processor and bit slice-full adder using a single electron trapping device

A new method is proposed for implementing logic operations by using a single electron trapping (ET) device. Based on the storage and erasure characteristics of the device, each Boolean logic operation can be performed by the corresponding programming. The encoding method is efficient, since each bit is spatially encoded by a single pixel. The system is simple and the optical elements can be stacked together, so the structure is compact. Furthermore, the logic operations involving three or even more variables can be realized easily with the suggested architecture. All the operations are executed in parallel. As an example, a triple-in binary logic processor is demonstrated to perform bit-slice full additions. Experimental results are given.

Optical computing based on a selector logic

Optical logic operations based on a selector logic are proposed. Based on the parallelism of optics, the selector logic is realized by data beam selections through a polarization switching device and a birefringent plate. The optical selector unit proposed here is composed of a pair of 90° twisted nematic liquid crystal cells, a birefringent crystal plate, and a mask. Several logic gates (AND, OR, XOR, and XNOR gates) and a full adder are demonstrated based on the proposed optical selector logic. The parallelism of optics makes it easy to implement the selector logic. As a result, optical parallel logic operations are performed by cascading the selector units and the interconnection problems for a large scale logic circuits can be avoided.

Self‐programming optical parallel logic

AbstractBased on dual‐rail spatial coding, in this article a self‐programming optical logic concept is proposed. The self‐programming is formulated by different coding of input images. Thus all 16 binary logic operations can be realized optically in parallel. Experimental results are demonstrated.

Multi-input optical parallel logic processing with the shadow-casting technique

The lensless shadow-casting technique for coded pattern processing usually accommodates two inputs at a time to perform desired logical operations in parallel. A method of binary encoding is proposed that can accommodate multiple input patterns for simultaneous processing. With the proposed multiple-input encoding a carry-look-ahead technique of binary addition is developed that requires fewer processing steps than the conventional ripple-carry method. Experimental results for a few logic-processing operations are included to establish the validity of the proposed technique.

Programmable optical triple-in binary logic processor using multiple-imaging

An optical parallel logic system for performing all 256 logic functions of three input binary patterns is proposed. The system is based on multiple-imaging and dual-rail encoding techniques, and logic operations are programmed by polarization customizing. Experimental results are presented, too.

Iterative processing on a hybrid optical parallel array logic system with a selectable coherent correlator

A new version of an experimental system of an optoelectronic hybrid optical parallel array logic system is constructed. The experimental system is composed of a two-dimensional correlator with selectable holographic filters and parallel electronic circuits. The system can process images consisting of 3 × 3 pixels at a time. Several types of processing are achieved both without and with dynamic selection of the holographic filters. On the experimental system, parallel operations of several logical functions and data transmission are demonstrated. Processing rates of iterative operation without and with filter selection are 278 and 143 frames/s, respectively.

Bistable Spatial Light Modulator Using Guest-Host Liquid Crystal and Bi12GeO20 Photoconductive Crystal

This paper describes a new bistable spatial light modulator consisting of a guest-host type of 90°-twisted nematic liquid crystal layer and a Bi12GeO20 photoconductor. The optical bistability is generated by an internal electro-optic feedback effect based on the nonlinear transmittance property of the guest-host liquid crystal layer and the photoconductive property of the Bi12GeO20 crystal. This device has various optical threshold functions, where the optical threshold level is easily controlled by varying the drive voltage of the device or its frequency. Optical image binarization and optical parallel logic operations based on optical bistability are realized by illuminating the liquid crystal layer with blue light. It has a limiting resolution of 25 lp/mm, and the rise and decay times of the device are approximately 30 ms and 90 ms, respectively.

並列光コンピューティングのためのコヒーレント光による光入力デバイス

Superposition of complex fields generated by a hologram and its intensity detections facilitate parallel optical logic operations Coherent lights must be used for inputs, since this holographic logic operation is based on coherent optical processes Therefore, coherent input devices are required for parallel optical computing Three important properties of these coherent input devices are contrast, amplitude deviation, and phase deviation. In this paper, we discuss the tolerance limits of these three properties Experiments using a liquid crystal display as a coherent input device are studied.

Solid-state integrated optical parallel dual-rail logic gate module

Based on the dual-rail logic, an optical parallel and cascadable binary logic gate is proposed, which consists of prisms for beam splitting and combining and controllable halfwave plates for customizing logic operations. All sixteen logical operations can be implemented. Electro-optic crystals are suggested as the controllable halfwave plates. A compact solid-state integrated gate module can be constructed by packaging the prisms, the crystals and the spatial light modulators.

Parallel Neighborhood Operation System by Optical Parallel Logic Gate and Optical Interconnection with Prisms

Parallel neighborhood operations are very useful for image processing. A system that optically implements the operations is presented. The system consists of an optical parallel logic gate, a simple multiple-imaging system and electronic feedback circuits. The experimental results of several binary image processings are presented by use of the system, and a new algorithm for extraction of corners is proposed.

Real-time parallel optical logic operation using photorefractive two-wave mixing and fringe-shifting techniques

The coupling effect between phase and intensity in photorefractive two-wave mixing in a Bi(12)SiO(20) crystal is demonstrated. By using interference fringe-shifting techniques that are executed by a Mach-Zehnder interferometer, an optical parallel logic operation system that is based on the coupling effect is implemented.

Cascade-connective optical parallel logic processor using electrophotonic devices

To perform image or arithmetic processing optically, it is necessary that a large number of required optical processors be connected in a series. For such cascade connections, however, coding and decoding processes are undesirable because of the necessity for the complicated hardware that often results. We propose here a new logic algorithm for application to cascade connections, which utilizes, in place of coding and decoding processes, true logic signals and their complements. Its optical implementation is also discussed. A processing module is constructed from electro-photonic devices referred to as vertical to surface transmission electro-photonic devices, a ferroelectrical liquid-crystal spatial light modulator, and a planar microlens array. Its logic operations are successfully demonstrated.

Cascadable binary pattern logic processor using multiple-imaging

An optical parallel logic processor is proposed which utilizes multiple-imaging with polarization customizing and spatial encoding with the combination of the variable pattern and its complement. The principle is based on the function logic block and cell. Particularly, the output has two patterns, which can be independently programmed for different logic functions. As they represent a logic function and its complement, the input and the output are in the same encoding style and the processors are cascadable. Examples of applications are shown. Experimental results are given, too.

Opto-electronic hybrid optical parallel array logic system

Opto-electronic hybrid optical parallel array logic system

An Optical Parallel Computing System with Electronic Feedback Circuits

A hybrid optical computing system having a parallel optical logic gate and electronic feedback circuits is proposed. With this system, various repeated parallel computations can be performed.

Experimental verification of parallel processing on a hybrid optical parallel array logic system

A hybrid digital optical computing system is constructed, a variation of the optical parallel array logic system (OPALS). The OPALS is a general-purpose digital optical computing system based on optical array logic, in which image coding and 2-D correlation are used to achieve parallel logical operations. In the constructed system, 2-D correlation for optical array logic is performed optically with a modified multireflective correlator; the other procedures in optical array logic are achieved by electronics including a TV feedback system. We have verified correct execution of programs written by optical array logic on the system. Although the processing speed of the system is still slow because of the sequential process in electronics, it can be drastically improved by replacing the sequential processing devices with parallel ones.