Coder/decoder with an optical programmable logic cell

Applied Optics, 1988

General characteristics and advantages of 2-D optical cellular processors are listed and discussed, with reference to the concepts of cellular automata, symbolic substitution, and neural nets. The role of optical interconnections and of quasilinear processing combining linear array operations and pointwise nonlinearities is highlighted. An architecture for optical implementation of cellular automata is introduced; it features high density 3-D optical shift-invariant interconnections and programmability of the interconnection pattern through adequate use of holographic connectors.

Scopus : Ilkogretim Online - Elementary Education Online, 2021; Vol 20 (Issue 6): pp. 4778-4793 http://ilkogretim-online.org, 2021

The applications that need high-speed decoding/encoding, optical packet routing/switching, ultrafast computation, and code conversion look poised to benefit from this new optical technology. There was a proposal for an optical decoder and encoder in the prior chapter. One of the benefits of signal (optical) processing is the range of analysis options it gives. It is impossible to create optical parts without optical logic gates. In this article, design and simulation of optical code converters has been discussed.

Applied Optics, 1994

The implementation of what we believe to be the first stored-program digital optical computer is described. The implementation domain consists of lithium niobate directional couplers that are modified to provide optical control and are interconnected with single-mode fiber. The architecture is also the first to employ time-of-flight synchronization. That is, there are no flip-flops used as synchronizing memory elements. Synchronization is achieved by the precise timing of the arrival of information at all points of interaction. The design is a minimal one, employing only 62 directional couplers. Previous papers have discussed the primary architecture and synchronization conditions for the machine. Here we focus on the secondary architecture, construction, debugging, and performance of the machine.

Applied Optics, 1984

A general technique is described for implementing sequential logic circuits optically. In contrast with semiconductor integrated circuitry, optical logic systems allow very flexible interconnections between gates and between subsystems. Because of this, certain processing algorithms which do not map well onto semiconductor architectures can be implemented on the optical structure. The algorithms and processor architectures which can be implemented on the optical system depend on the interconnection technique. We describe three interconnection methods and analyze their advantages and limitations.

Nanomaterials

For many years, optics has been employed in computing, although the major focus has been and remains to be on connecting parts of computers, for communications, or more fundamentally in systems that have some optical function or element (optical pattern recognition, etc.). Optical digital computers are still evolving; however, a variety of components that can eventually lead to true optical computers, such as optical logic gates, optical switches, neural networks, and spatial light modulators have previously been developed and are discussed in this paper. High-performance off-the-shelf computers can accurately simulate and construct more complicated photonic devices and systems. These advancements have developed under unusual circumstances: photonics is an emerging tool for the next generation of computing hardware, while recent advances in digital computers have empowered the design, modeling, and creation of a new class of photonic devices and systems with unparalleled challenges....

SPIE Proceedings, 1999

A chaotic output was obtained previously by us, from an Optical Programmable Logic Cell when a feedback is added. Some time delay is given to the feedback in order to obtain the non-linear behaviour. The working conditions of such a cell is obtained from a simple diagram with fractal properties. We analyze its properties as well as the influence of time delay on the characteristics of the working diagram. A further study of the chaotic obtained signal is presented.

Applied Optics, 2011

Logic units are the building blocks of many important computational operations likes arithmetic, multiplexer-demultiplexer, radix conversion, parity checker cum generator, etc. Multifunctional logic operation is very much essential in this respect. Here a programmable Boolean logic unit is proposed that can perform 16 Boolean logical operations from a single optical input according to the programming input without changing the circuit design. This circuit has two outputs. One output is complementary to the other. Hence no loss of data can occur. The circuit is basically designed by a 2 × 2 polarization independent optical cross bar switch. Performance of the proposed circuit has been achieved by doing numerical simulations. The binary logical states 0; 1 are represented by the absence of light (null) and presence of light, respectively.

Applied Optics, 1984

This paper studies the problem of digital logical or arithmetical optical processors that can be optically connected without any transducers to obtain maximum performance from the optics. After some comments on the double-diffraction linear systems, we examine FWM configurations, and describe optical computing units which combine FWM and amplitude coding. We show that programmable multiplexed operators can be implemented, using the probe signal as a control function. Finally, an optical equivalent of a transistor is proposed.

2000

The Optically Programmable Gate Array (OPGA), an optical version of a conventional FPGA, benefits from a direct parallel interface between an optical memory and a logic circuit. The OPGA utilizes a holographic memory accessed by an array of VCSELs to program its logic. An active pixel sensor array incorporated into the OPGA chip makes it possible to optically address the logic in a very short time allowing for rapid dynamic reconfiguration. Combining spatial and shift multiplexing to store the configuration pages in the memory, the OPGA module can be made compact. The reconfiguration capability of the OPGA can be applied to solve more efficiently problems in pattern recognition and database search.

Applied Optics, 1988

Regular free-space interconnects such as the perfect shuffle and banyan provided by beam splitters, lenses, and mirrors connect optical logic gates arranged in 2-D arrays. An algorithmic design technique transforms arbitrary logic equations into a near-optimal depth circuit. Analysis shows that an arbitrary interconnect makes little or no improvement in circuit depth and can even reduce throughput. Gate count is normally higher with a regular interconnect, and we show cost bounds. We conclude that regularly interconnected circuits will have a higher gate count compared with arbitrarily interconnected circuits using the design techniques presented here and that regular free-space interconnects are comparable with arbitrary interconnects in terms of circuit depth and are preferred to arbitrary interconnects for maximizing throughput. 1. Introduction All-optical digital computers have the potential for high speed, cheap communications, and massive parallelism. Logic gates based on nonlinear dielectric constants were investigated theoretically in the early 1960s by von Neumann. 1 In the last few years optical bistable devices, 2 ' 3 nonlinear Fabry-Perots, 4 ' 5 and hybrid electrooptic devices 6 have been studied experimentally. These results encourage development of architectures suitable for optics. Historically, two architectural approaches have dominated the field. One approach uses integrated optics to interconnect optical logic devices. A system designed with this approach is architecturally similar to a conventional computer, with logic gates connected in arbitrary configurations. This similarity means that an optical computer designed with this approach is worth building only if it can be made more cheaply or more powerful. An alternative approach makes use of 2-D arrays of devices interconnected in free space. This approach uses space-variant interconnects (provided by holograms) or space-invariant regular interconnects (provided by beam splitters). We prefer the space-invariant regular interconnect approach for simplicity, extensibility, and high throughput. To take advan