bluuebunny/crossref_metadata_2025 huggingface dataset:
High threshold, Thorium-free dielectric multilayer reflector for high-power middle infrared Lasers
Authors: Xiong Shengming , Zhang Yundong
Published: February 2023

ThF4
is widely used as standard low index material in optical coatings on infrared optics at 2.0- 12.0μm wavelength regions. Since Th is radioactive and toxic, handling of this material in film production, e.g. running and maintenance of the vacuum chamber, requires special investments for protection of the operators, and for eliminating pollution of the environment. Therefore, the search for other, less problematic materials as substitutes has been the subject of some earlier studied[1,2].
Mathematical Methods of Investigation Limit Possibilities of Interference Coatings For The Reaching of the Given Complex of the Properties
Authors: Gusev Evgeny L.
Published: February 2023

The problem working interference coating with given complex of the properties is investigated already many years. Importance this problem is connected with wide application of the interference coating in different fields physics and technics. The most general approach to the decision of the problems of optimal synthesis is variational. The quality criteri characterize degree of nearness of the functional characteristics the projecting coatings to the demanded.
Discrete layer thickness modulated designs: spacing of multiple stopbands
Authors: Perilloux B. E.
Published: February 2023

The optical thickness of discrete, homogeneous, thin film layers in a quarterwave stack can be modulated according to the recently developed layer modulation theory (LMT)1. Unlike rugate filters with modulated refractive index and suppressed high order stopbands, LMT structures produce harmonic and non-harmonic stopbands of quarterwave stacks. The adjustable frequency spacing of two (or more) stopbands using LMT structures can be predicted from analytical These LMT structures can be used instead of multiple quarterwave stacks, and are not constrained to the spacing of harmonic stopbands from first or higher order quarterwave stacks.
Application of Simulated Annealing to Multilayers Reverse Engineering.
Authors: Boudet T. , Chaton P , Berger M. , Lartigue O.
Published: February 2023

Knowledge and control of a technological process require efficient tools to have a good insight during and after deposit. In situ controls have many advantages because they provide a real time insight on the changes which occur in the deposit with a certain accuracy. However, the in situ measurement does not enable real time feedback on the technological parameters. We therefore developed techniques to characterize samples after deposition. We will show in this paper that the complementarity between optical and X-ray techniques can lead to very fine results. Our deposition chamber is provided with an original system which enables a sampling of some monolayers from the stack. The Investigation of these monolayers help to make a reverse engineering on stacks of several layers.
Suppression of alias and replica noises in phase holograms using fractal topologies
Authors: Ho I-Lin , Chang Chun-Ling
Published: February 2023

Two-dimensional fractal topologies featuring (scaling) self-similarity, dense set of Bragg (diffraction) peaks, and inherent rotation symmetry, which are not achievable with regular grid-matrix geometries, exhibit optical robustness against structural damage and noise immunity of optical transmission paths. In this work, we numerically and experimentally demonstrate phase holograms using fractal plane-divisions. By taking advantage of the symmetries of the fractal topology, we propose numerical algorithms to design the fractal holograms. This algorithm solves the inapplicability of the conventional iterative Fourier transform algorithm (IFTA) method and enables efficient optimizations of millions of adjustable parameters in the optical element. Experimental samples show that the alias and replica noises in the image plane of fractal holograms are clearly suppressed, facilitating applications for high-accuracy and compact requirements.
GaAs Integrated Optoelectronic Circuits
Authors: Milano Raymond A.
Published: February 2023

The trend in component technology is toward higher data rates and increasing numbers of input/output ports. Silicon VLSI and VHSIC chips may have 50-100 signal pins each operating at data rates up to 50 Mb/s. Gallium arsenide IC's, while of lower complexity, operate at data rates of 1-4 Gb/s. As the data rates and number of I/O ports increases chip, board, and subsystem interconnection becomes increasingly problematical using conventional approaches ( e.g. coaxial cable, twisted wire pairs). Difficulties occur primarily due to wire count, power constraints, and limited channel data capacity. Clearly, an alternative interconnect technology is required in order to implement the high performance systems currently being contemplated for data and signal processing applications.
Optical Logic and Memory Functions Based on Polarization-Bistable Semiconductor Lasers
Authors: Liu J.M. , Chen Y.C.
Published: February 2023

A digital optical computation system must store binary optical signals in addition to performing optical logic operations. Theoretically, any digital system can be constructed entirely from NAND (or NOR) gates and flip-flops, in which the gates perform the logic and the flip-flops perform memory functions. Recently, we have observed direct polarization switching [1] and polarization bistability [2] in InGaAsP/InP lasers. With very simple circuitry, we have demonstrated operations of optical logic gates and flip-flops based on these lasers.
Observation of Optical Bistability in InGaAsP
Authors: Sharfin W. , Dagenais M.
Published: February 2023

We are reporting the first observation of optical bistability in InGaAsP. The motivation for much of the present research in all-optical signal processing is that optical devices can perform a large number of independent operations simultaneously, rather than sequentially. In cases in which sequential operations would constitute a bottleneck in all-electronic systems, a great deal of time may be saved by using optical devices as part of a larger hybrid system. In order to facilitate interfacing of optical and electronic components wavelength standardization at 1.3 microns is desirable for compatibility with existing semiconductor laser sources and fibers.
Cascadable Digital Optical Logic Circuit Elements in the Visible and Infrared: Prospects for Fast Array Processors
Authors: Smith S.D. , Walker A.C. , Wherrett B.S.
Published: February 2023

An extensive experimental and theoretical programme in our laboratory and in conjunction with a number of other European laboratories has now developed a series of optical circuit elements including optically bistable switches capable of steady state cw (operation) combined with external address for both visible and infrared wavelengths. The devices are sufficiently controllable that the characteristics may be varied to give bistable switches, bistable memories, latchable gates, resettable gates or analogue amplifying elements or transphasors.
Phase Conjugate Optical Four Wave Mixing Devices for Optical Logic, Computation and Interconnect
Authors: Eichmann George
Published: February 2023

Optical phase conjugate devices utilize a variety of physical phenomena to exactly reverse the direction of propagation of an incident optical beam.. A recent survey of some of the possible optical devices is available1. The interest in using these devices for optical logic, computation and interconnect stems from the ultrafast, subpicosecond, switching speed that optical four wave mixing (FWM) devices are able to achieve2. For all optical logic network both the input and the output logic variables must be optical quantities. Four-wave mixing elements, because they require a number of optical beams for its operation, are candidates for such networks. Optical FWM logic assignments use various polarization and amplitude coding schemes to realize canonical logic, such as an AND and an OR, gate configurations3-5.
An Integrated Acoustooptic Module for Optical Computing
Authors: Tsai C. S. , Zang D. Y. , Le P.
Published: February 2023

Realization of optical signal processing and computing functions in a waveguide substrate has long
been considered as one of the major applications of integrated optics. A variety of active
guided-wave devices that have been developed recently are being suggested for this
purpose(1-3). For example, the planar waveguide AO Bragg cells in
LiNbO3(1) are now widely used in the development of integrated optic modules
for spectral analysis(4) and correlation(5) of wideband RF signals. Spherical
waveguide AO Bragg cells in LiNbO3 are also being explored(6). In this paper,
we report on the first successful experimentation of AO Bragg diffraction in a LiNbO3
channel-planar composite waveguide. Efficient and wideband Bragg diffraction has been achieved using
the SAW centering at 500 MHz and the optical wavelength at 6328 Å. By incorporating a
channel-waveguide array, a planar waveguide, a microlens array, an AO Bragg cell, and an integrating
lens in the same substrate as shown in Figure 1, we have realized a compact integrated optic module
which can potentially perform a variety of optical computing functions.
What Optics can do for the Digital Optical Computer
Authors: Lohmann Adolf
Published: February 2023

The hope is that the digital optical computer (DOC) will supplement the capabilities of the established electronic computer. To achieve this goal the DOC has to catch up technologically with the electronic computer in order to be compatible. Will it be possible for the DOC to catch up inspite of a delay by more than 30 years? A growing number of researchers apparently believes so.
Architectures of Optical Cellular Logic Computers
Authors: Yatagai Toyohiko
Published: February 2023

Recently optical computing techniques have been developed, and the feasibility of optical computers is discussed. We will describe optical implementations of cellular logic computers (CLCs) which are used for the digital electronic computation of two-dimensional logical neighborhood functions. Perhaps the most obvious application of such an optical computer is in pattern recognition as it pertains to image data processing.
Potential Speeds for Integrated Optical Computing
Authors: Verber C. M. , Smith B. T.
Published: February 2023

It has been widely assumed that, provided the hardware problems can be overcome, there are significant intrinsic speed advantages to optical approaches to certain computational problems. Methods for achieving high accuracy using optical analog components to execute digital algorithms(1) have further increased interest in optical computing. It is the purpose of this paper to examine some of the factors which determine the speed of integrated optical computational devices, and to present the results of an initial attempt to compare the performance of optical and electronic approaches to matrix-vector multiplication (MVM).
Design of an Optical Residue Arithmetic Matrix Vector Multiplier Using Holographic Table Lookup
Authors: Habiby S. F. , Collins S. A.
Published: February 2023

The design of an optical matrix multiplier is presented. In it elementary residue arithmetic1 addition and multiplication operations are broken into simple parallel mapping units. The input to these units is position-coded and translated via holographically stored tables into useful light valve forms. Addition and multiplication mapping units are then combined into the full matrix-vector multiplier. The matrix elements are provided by a microprocessor-controlled CRT and the vector elements are provided by position coded optical fiber input.
Architectural and Hardware Issues in High Accuracy Optical Matrix Processors
Authors: Athale Ravindra A. , Lee John N.
Published: February 2023

Matrix operations, such as vector-matrix and matrix-matrix multiplication, are of great interest since a large variety of problems in signal processing, image processing and computing can be cast in terms of linear vector space operations. Optical systems, with their ability to multiply and add a two-dimensional arrays of numbers and to provide an arbitrary interconnection between them, have been investigated intensively in the recent past for performing matrix operations. Most of these optical systems were linear in their characteristics and hence operated in an analog mode. This restricted the accuracy achievable to 6-8 bits. One way of overcoming this limitation is to resort to nonlinear optical devices which can implement the basic operations involved in binary arithmatic, such as AND, OR, NOT, logic operations. The other approach involves using linear operation of convolution in performing pseudo-binary multiplication (the bits are allowed to assume values >1) as first suggested to optics community by Whitehouse and Speiser1. Psaltis, etal applied this concept to a two-dimensional optical correlator and demonstrated high accuracy correlation of one-dimensional binary encoded sequences.2 In the last two years several researchers proposed schemes for merging this and related concepts with different architectures for optical matrix processing.3-6 It is the aim of this paper to systematically study the different architectures that result; compare their requirements of: a) input devices, b) output devices, c) optical systems and d) post processing electronics; and try to draw some general conclusions.
The Role of Optics in Future Computational Systems
Authors: Neff John A.
Published: February 2023

The next two decades will see major advances into the incorporation of intelligence into computational systems. Since throughput rates will continue to dominate systems issues, optics most likely will have a major role to play, and we would be remiss not to identify these opportunities at this early stage while most efforts are still focussed on algorithm development. Optical computing presents a highly parallel environment which is particularly adept at the rapid generation of Fourier transforms, correlation functions, and convolution. A natural extension of these capabilities is the optical implementation of search and sort algorithms, which form the backbone of symbolic computing. Associative processing, which is the general class of neural analogue computing systems whose computation structure is based on models of human thought and reasoning processes, may be ripe for optical processing due to the relative ease with which optics can realize the extensive interconnect networks so vital to such processing.
An Optical Random Number Generator for Monte Carlo Calculations
Authors: Martino Anthony J. , Morris G. Michael
Published: February 2023

Many of the tasks that are performed on a digital computer require a source of random numbers that are independent and fit a specified probability density. The usual random number generator provides numbers that are uniformly distributed over the interval (0,1). A transformation is then employed to obtain deviates that follow the specified distribution. A complicated transformation can reduce the generation rate by as much as an order of magnitude or more.
Pattern Recognition and Logic with Optical Gates
Authors: Hassoun M. H. , Arrathoon R.
Published: February 2023

Threshold logic has traditionally been reserved for purely academic considerations related to the theory of switching functions. Modern VLSI circuitry is ill-suited to the implementation of threshold logic devices and relies exclusively on simple gates for its computational power. Recent developments in integrated optics have shown1 that it is possible to optically implement a threshold function.
Monte Carlo Matrix Inversion Using an Optical Random Number Generator
Authors: Martino Anthony J. , Morris G. Michael
Published: February 2023

Matrix inversion and other linear algebra problems are a frequent subject of interest in the field of optical computing. In this paper we describe laboratory experiments involving Monte Carlo matrix inversion using an opto-electronic hybrid system. The hybrid system is composed of an optical random number generator coupled to an electronic digital processor.
Monte-Carlo Processor Arrays Using Optical Random Number Generators
Authors: Devos F. , Madani K. , Chavel P. , Taboury J.
Published: February 2023

The use of optical phenomena for the generation of random number arrays has been introduced by Morris and his coworkers in recent publications {1-3}.
Optical Interconnects using Resonated Holograms
Authors: Collins Stuart A.
Published: February 2023

This paper deals with optical interconnects formed by thick holograms with mirrors to resonate them. A calculation for a design is submitted which predicts good efficiency, small angular bandwidth, and large numbers of interconnects with modest holographic capability.
Multilayer Optical Learning Networks
Authors: Wagner Kelvin , Psaltis Demetri
Published: February 2023

In this paper we present a new approach to multilayer neural network learning which is based on holographically interconnected nonlinear Fabry-Perot etalons. The network can learn the interconnections that form a distributed representation of a desired pattern transformation operation. The interconnections are formed in an adaptive and self aligning fashion, as volume holographic gratings in photorefractive crystals. Parallel arrays of globally space integrated inner products diffracted by the interconnecting hologram illuminate arrays of nonlinear Fabry-Perot etalons for fast thresholding of the transformed patterns. A phase conjugated reference wave interferes with a backwards propagating error signal to form holographic interference patterns which are time integrated in the volume of the photorefractive crystal in order to slowly modify and learn the appropriate self aligning interconnections. A holographic implementation of a single layer perceptron learning procedure is presented that can be extended to a multilayer learning network through an optical implementation of the backward error propagation (BEP) algorithm1.
Switch Power Drift in Optically Bistable ZnSe Interference Devices
Authors: Campbell R.J. , Mathew J.G.H. , Smith S.D. , Walker A.C.
Published: February 2023

Optically bistable devices based on nonlinear thin-film interference filters have been reported by Smith et al [1] and Weinberger et al [2] and have been shown to be suitable for use as logic elements in digital optical circuits [3] and pattern recognition applications [4]. These devices use ZnSe or ZnS as the active material and rely on thermally induced changes in the refractive index to provide the required nonlinear response.
Ferroelectric Liquid Crystal Spatial Light Modulators
Authors: Armitage D. , Thackara J. I. , Clark N. A. , Handschy M. A.
Published: February 2023

The ferroelectric liquid-crystal (FLC) phase is a relatively new development in liquid crystals. The basic symmetry restrictions demanded by ferroelectricity are met by the chiral smectic-C liquid-crystal phase. The chirality or lack of mirror symmetry at molecular level gives rise to a spiral polarity or helioelectric structure. The helix can be unwound by an applied electric field to create a uniform FLC. However, this is not the most favorable device arrangement.
Optical Neural Computers
Authors: Psaltis Demetri
Published: February 2023

The development of optical computers of any type is based on the notion that semiconductor technology imposes limitations in the performance of current computers which prevent them from being effectively used for the solution of a class of interesting computational problems. If optics is used instead, these limitations will be lifted and we will therefore be able to now solve these interesting problems. Global connectivity is perhaps the most distinctive feature of optics vis-a-vis semiconductor technology, and the development of optical neural computers can be viewed as an attempt to exploit this feature. In a neural network each elementary computational unit, the neuron, directly communicates to thousands of others, while in electronic computers each gate is typically connected to only two or three gates. With optics it is feasible to realize the dense connectivity that is evident in neural networks. This provides the impetus for examining neural network models of computation to get ideas about how to build optical computers whose performance is clearly better than their electronic counterparts.
Optical Implementations of Neural Computing
Authors: Athale Ravindra A.
Published: February 2023

Achieving performance comparable to human beings in speech recognition, visual perception, motor control and knowledge acquisition, representation, and processing is one of the most difficult and exciting challenges facing the information processing research community. Recently neural net models of computation have been investigated as a novel approach for solving these problems. These proposed models are only loosely based on the known and postulated characteristics of biological systems and no claim is usually made for these models to be biologically accurate.
Implementation of Dynamic Hopfield-like Networks using Photorefractive Crystals
Authors: Wilde Jeff , Hesselink Lambertus
Published: February 2023

We present an architecture for optically implementing a digital associative memory using a coherent optical system. Bipolar information is holographically phase encoded in a photorefractive crystal and upon readout is interferometrically phase decoded.
Competitively Inhibited Optical Neural Networks Using Two-step Holographic Materials
Authors: Lemmon Michael , Kumar B.V.K. Vijaya
Published: February 2023

Competitively inhibited networks automatically form nonparametric representations of density functions and therefore can be used as MAP predictors on a variety of problems. The dynamics of this class of networks is briefly reviewed and an optical implementation is proposed based on two-step holographic materials.
High-Speed Parallel Optical Processors of Photorefractive GaAs
Authors: Cheng Li-Jen , Liu Duncan T.H.
Published: February 2023

It is known that a photorefractive crystal can act as a phase conjugate mirror via four-wave mixing or self-pumped phase conjugation. The use of a phase conjugate mirror in the interferometric system for parallel mathematic operations has been reported[1-6]. The photorefractive materials used are BaTiO3[l-5] and Bi12SiO20[6]. The phase conjugation process can improve dynamic stability by reducing the sensitivity to beam path fluctuations and alignment. However, the slow responses of these materials make operations not only slow, but also sensitive to environmental fluctuations, such as air turbulence and vibrations of time constants shorter than those of the material response time.
Integration of Polymer Waveguides with HOE On GaAs, LiNbO3, Glass And Aluminum Substrates to Provide massive Fan Out (104/node) Optical Interconnects for Computing
Authors: Chen Ray T. , Phillips William , Jannson Thomasz , Pelka David
Published: February 2023

In this paper, we report good quality waveguides (loss<ldb/cm) formed from pure gelatin, i.e., gelatin without ammonium dichromate. Pure gelatin solutions with various water to gelatin ratios were spun on top of soda-lime glass (N=1.512 at 632.8nm). When gelatin first goes into aqueous solution the molecules exist as single chains encircled by water molecules. Upon standing at temperatures below 30 °C, solutions containing more than 1% gelatin become rigid through cross linking and exhibit rubber-like mechanical properties. In this work optical waveguides were thus formed. The waveguiding properties were examined through the prism coupling method. The measured effective indices for TE and TM guided waves were the same for each sample. This implies that no birefringence exists in the gelatin layer. The guiding layer index profiles of multi-mode gelatin waveguides were determined by the inverse WKB method commonly used in integrated optics[l]. Graded index profile of a multi-mode waveguide can be accurately determined by IWKB method. Step indices can also be determined through this method with a small deviation at the turning point [2]. The calculated index profile of sample #D1, composed of 15 grams of gelatin, 100 CC water and spun at 100 rpm, is given in Fig.1, curve A. The measured surface index of various samples with different water-gelatin ratios is shown in Fig.2. Surface index variation from 1.522 to 1.543 was observed. Each data point of Fig.2 was determined by the 0th order mode of the corresponding multimode waveguide (total number of modes >10). Since the guiding layer has a step index, the 0th order mode effective index is almost equal to the surface index. The plotted index profiles of the various gelatin waveguides before wet processing demonstrates that the gelatin layer forms a step index layer and the index refraction increases as the gelatin ratio increases.
2D Optical Trimmed Inverse Augmented Data Manipulator Networks
Authors: Cloonan T. J. , Herron M. J.
Published: February 2023

The network topologies that have been proposed for electronic switching systems must often be modified to satisfy the unique constraints placed on the system by the use of photonic technologies. This paper presents modifications to a class of O(N log2N) multistage interconnection networks known as Inverse Augmented Data Manipulator (IADM) networks[1] (Fig. 1) which are based on Plus-Minus-2
i
connection patterns. The modified Inverse Augmented Data Manipulator network requires that some of these interconnections be trimmed from the edges of the network to simplify the optical components required in a photonic design, so the network is called the Trimmed Inverse Augmented Data Manipulator (TIADM) network (Fig. 2). The TIADM network can be modified (as in Fig. 3) to have three-dimensional interconnections between two-dimensional stages of nodes, and this network will be called a two-dimensional (2D) TIADM network. The large number of connections required in the 2D TIADM make the network attractive as a potential candidate for photonic switching architectures.
Alignment and Performance Tradeoffs for Free-Space Optical Interconnections*
Authors: Tsang Dean Z.
Published: February 2023

Optical interconnections are of interest as a high-speed replacement for electrical interconnections in digital computers1,2 for applications between mainframes, modules, boards, VLSI circuits,3 and even between points within a VLSI circuit.4 The effect of angular and positional alignment on the optical efficiency of tree-space board-to-board optical interconnections is considered here for inexpensive lenses and shown to result in good system performance if reasonable care is taken in the design and assembly of the system. An experimental system was assembled and shown to operate at a rate of 1 Gb/s, a system efficiency of 18.8%, and an estimated aligned optical efficiency of 93%.
Light effective perfect shuffle using Fresnel mirrors
Authors: Sheng Yunlong , Arsenault Henri H.
Published: February 2023

Three-dimensional optical multistage interconnection networks (MINs) can dynamically connect a 2-D array of NxN inputs to a 2-D array of NxN outputs. They exploit the 3-D nature of light propagation in free space for high density and high speed interconnections which are difficult to implement with planar electronic VLSI technology.
The Energetic Advantage of Analog over Digital Computing
Authors: Caulfield H. J.
Published: February 2023

Our goal is to examine the energetics of computation for analog and digital computers. A careful analysis of digital computers has already been performed (1). That analysis suggests that each computation must have enough energy to overcome thermal noise. That is the energy per digital calculation,
ED', must satisfy where k is Boltzmann's constant and T is the operating temperature.
Computational Origami - The Folding of Circuits and Systems
Authors: Huang A.
Published: February 2023

A technique which regularizes and folds circuits and systems to match the parallelism of optics is presented.
All-Optical “Game of Life” Computer
Authors: Domash Lawrence H. , Cronin-Golomb Mark
Published: February 2023

Although a variety of optical computing architectures have been analyzed and many individual devices reported, to date few working optical computers have been demonstrated performing a complete, self-contained, recognizable computational function. A conceptually simple but significant computing architecture which appears accessible to complete all-optical implementation is the cellular automaton (CA). Murdocca discussed the CA in comparison with symbolic substitution (1). Taboury et al showed how general cellular processors could be realized using sets of holograms (2).
Multiplexed Waveguide Hologram for Optical Processing and Computing
Authors: Lin Freddie
Published: February 2023

The concept of using holograms in optical processing and computing has been found in a variety of areas such as optical interconnects [1], optical associative memory [2] and optical computing systems [3]. In conventional holography, holographic optical elements (HOEs) are generally located in three-dimensional free space (see Figure 1(a)). This type of 3-D free-space holograms has important limitations. First, alignment problems are critical. If the sources and detectors are not in exact 3-D alignment with the holographic elements, performance suffers possibly to the point where the system becomes inoperative. Second, and more importantly, conventional 3-D Bragg holographic elements have low angular and wavelength selectivity (i.e., multiplexing) due to the limited hologram thickness (t ~ 20μm, for dichromated gelatin). Although multifacet holograms [4] are proposed, to improve performance, they suffer from diffraction-limited because of the small facet apertures.
Neural Network Models Based on Optical Resonator Designs
Authors: Gustafson Steven C. , Little Gordon R.
Published: February 2023

This paper specifies a class of neural network models in a form suitable for performing computer simulation experiments and assessing possible optical implementations. These models are consistent with optical resonator designs that may include dynamic holograms and thresholded phase conjugate mirrors. The specification obtained here could be of near-term value in the development of new pattern recognition algorithms.
Two Beam Coupling Polarization Properties in BSO Using Alternating Electric Fields
Authors: Pauliat G. , Roosen G.
Published: February 2023

Because of the inherent loss of optical systems, image amplification can be required in massively parallel optical architectures. This amplification can be obtained through the two wave mixing interaction in photorefractive crystals [1]. However, for sensitive material such as sillenite crystals one has to compensate for the relatively low electrooptic coefficient by an appropriate enhancement recording technique. One method to enlarge the photorefractive gain is to apply an alternating field to the crystal [2]. Consequently all the properties of the amplified beam (phase, polarization and intensity) will oscillate at the electric field frequency. Therefore, special care should be taken when inserting such an amplifier in an optical system so that the time dependent characteristics of the amplified beam are not disturbing the operation of any next non linear device. For this reason, using the coupled wave formalism [3], we study in the following all the features of the amplified beam under an alternating electric field.
Band-tunable multichannel scale invariant pattern recognition system with zone plates
Authors: Minhua Liang , Shudong Wu , Liren Liu , Zhijiang Wang
Published: February 2023

Distortion invariant pattern recognition is wanted very much in real circumstances, such as robot vision, target tracking, pattern recognition and so on. Matched filter, also called the Vander Lugt filter, suffering from the requirement for the input object with the same scale size and orientation as the reference pattern, is hard to meet those requirements in the real circumstances. Many improvements, however, have been made on the technique of matched filtering recognition. The factor of scale is the one to which a system of matched filtering recognition is expected to immune.
An Optical-Holographic-Associative-Memory-Based Parallel Register Transfer Processor
Authors: Eichmann George , Kostrzewski Andrew , Kim Dai Hyun , Li Yao
Published: February 2023

A combinatorial logic circuit is an interconnected array of logic gates. However, for various arithmetic operations, iterative sequential computation is needed. To furnish feedback, memory elements, such as flip-flops or registers must be utilized. With this feedback, the overall logic circuit is a finite-state sequential logic machine. The use of optics to perform fast combinatorial logic processing was suggested1-3. However, for the various proposed combinatorial logic elements the efficient feedback generation is an active research area. To generate a sequential logic circuit, a viable hybrid approach is to use optics for both fast parallel logic and interconnect and high-speed bit-addressable electronics for storage and feedback1. In this paper, a specific hybrid sequential computing module, where optical array processors that perform the combinatorial logic and interconnect operations, are sandwiched between high-speed electronic parallelly-addressed storage registers, is described. This hybrid system can sustain various fast optical register transfer micro-operations (ORTMOs), operations that are the most primitive operations required for an optical digital computer. This new system will be referred to as an optical register transfer processor (ORTP).
The Relationship Between Photonic Switching and Optical Computing
Authors: Hinton H. S.
Published: February 2023

The purpose of this talk is to outline the relationship between the hardware requirements of photonic switching and optical computing systems. The majority of the talk will address the hardware requirements of digital optical switching and computing systems with the exception of a brief discussion on analog switching and computing. It will include a review and comparison of the devices, interconnects, and systems that have been proposed for both types of systems.
Digital Optoelectronic Processor Array Architectures for Vector-Matrix Multiplication
Authors: Feldman Michael R. , Guest Clark C.
Published: February 2023

High speed computation of the product of a vector and a matrix is desirable for problems in neural networks, signal processing, artificial intelligence and many other applications. If the number of elements in the vector is N, and the number in the matrix is N2, then a serial computer requires a time which grows at least as N2 to complete the computation. Many processing elements (PE's) can be combined to form a processor array in order to decrease the computation time. Electrically connected processor arrays are effective for locally connected parallel processing networks[1], A linear mesh can be used to perform the multiplication in time proportional to N [2], However to compute the product in shorter time, more complicated schemes with non local connection lengths are required. For such networks, the interconnections themselves are often responsible for a large percentage of the computation time, power dissipation and silicon area. Optically interconnected processor arrays can be employed to reduce this communication bottleneck. Previous work has shown that optical interconnections have advantages in terms of power dissipation and communication bandwidth for sufficiently long interconnection paths[3], and in terms of area for sufficiently complex connection networks[4].
Optical Binary Multiplication Based On a Non-Holographic Content Addressable Memory
Authors: Kostrzewski Andrew , Eichmann George , Kim Dai Hyun , Li Yao
Published: February 2023

A new fast binary multiplication scheme based on a non-holographic optical content addressable memory (CAM) and a sign/logarithm number (SLN) system is presented. The design and experimental demonstration of a 7-bit multiplier are presented.
3D-lntegration of Digital Optical Systems
Authors: Brenner K.-H.
Published: February 2023

The general goal of integration is to provide ease of fabrication, enhanced stability and compactness of complex systems by reducing the number of degrees of freedom in the assembly. Currently the term ’Integrated Optics’ represents two-dimensional planar integration. With a variety of techniques passive optical components have been integrated on a single substrate, guiding the light along predetermined paths /1/. By including electro-optic switching mechanisms and also, more recently, by integrating semiconductors planar integration of monolithic integrated optical circuits (OEICs) has become possible. Planar integration permits only a propagation of zero-dimensional optical signals. Furthermore the need of coupling into and out of wave guides generates interface problems lessening the advantages provided by integration.
Optical Modular Architectures for Multi-Layer Bam with 2-Dimensional Patterns
Authors: Lee Soo-Young , Lee Hyuek-Jae , Shin Sang-Yung
Published: February 2023

After the first demonstration of optically-implemented Hopfield model [1] many neural network models have been investigated for large-scale optical implementation [2-8]. The 1-dimensional Hopfield model had been extended for 2-dimensional patterns [2], and optical implementation of bidirectional associative memory (BAM) [3-5] and quadratic associative memory [6,7] had been investigated. Adaptive neural network models such as multi-layer perceptron [8] had also been demonstrated. However performance of the simple Hopfield model and BAM is very limited, and many adaptive learning algorithms are too complicated to be implemented efficiently by optics. Also, when a new pattern need be added to the existing system, the correlation matrix learning rule of both the Hopfield model and BAM requires simple addition to existing interconnection weights, while error back-propagation learning rule for multi-layer perceptron requires to bring over all the previously stored patterns. Recently we had extended the BAM into multi-layer architecture, of which performance is quite comparable to that of multi-layer perceptron [9]. This multi-layer BAM (MBAM) still utilizes correlation matrices for easy optical implementation with outer-product matrix formation or inner-product recall. In this paper optical system architectures for the MBAM are presented for 2-dimensional patterns, and several implementation issues are discussed.
Two-Dimensional Optical Buses for Massively Parallel Processing
Authors: Kawai Shigeru , Mizoguchi Masanori
Published: February 2023

Massively parallel processing systems have the serious problems of interconnection pathways between processors. Light beams are particularly appropriate for this purpose, because they can cross each other with no mutual interference.[1] Optical interconnections which satisfy this condition can be classified into two techniques, which involve two-dimensional waveguide[2]-[4] and free-space interconnections. These interconnections have no physical pathways. Taking into account pathway density and power efficiency, waveguide techniques are suitable for bus-connections between in-plane processors, while free-space techniques are suitable for interconnections between plane-to-plane processors. One of the authors has already proposed free-space interconnections using micro lens arrays for this purpose.[5] This paper describes an attempted implementation of the new optical buses using two-dimensional waveguides for parallel processing initially proposed by R. A. Linke.[6] Their principles are successfully demonstrated, using glass plates with concave lenses.
Passive Optical Array Generators
Authors: Taghizadeh Mohammad R. , Turunen Jari , Robertson Brian , Vasara Antti , Westerholm Jan
Published: February 2023

Recent progress in designing and manufacturing space-invariant optical array generators is described. We begin by demonstrating Dammann gratings [1] that generate even-numbered arrays as large as 128x128, and odd-numbered arrays of up to 201x201 spots. The concept of a hybrid hologram [2] is applied to the fabrication of array generators, and extremely high-efficiency (close to 90%) components are obtained. Several novel types of array generators with multiple phase levels are introduced. These can e.g. reconstruct arrays with different fan-out at different angles of incidence. The application of rigorous diffraction theory to design highly efficient and compact array generators is also discussed.
Filter Generation in Hybrid Electro-Optical Correlators Using Genetic Algorithm
Authors: Mahlab Uri , Shamir Joseph
Published: February 2023

The purpose of this work is to introduce into the field of optical pattern recognition the parallel approach of genetic algorithm (GA) [1, 2] replacing conventional serial procedures. We start with a short review of the procedure for iterative spatial filter generation in a 4-f correlator [3], proceed with the adaptation of GA and present experimental results.
Optical Matrix-Vector Implementation of Binary Valued Backpropagation
Authors: Brodsky Stephen A. , Guest Clark C.
Published: February 2023

Optical implementations of neural networks can combine advantages of neural network adaptive parallel processing and optical free-space connectivity. Binary valued Backpropagation1, a supervised learning algorithm related to standard Backpropagation2, significantly reduces interconnection storage and computation requirements. This implementation of binary valued Backpropagation used optical matrix-vector multiplication3 to represent the forward information flow between network layers. Previous analog optical network memory systems have been described4.
Effects of Imperfection in Spatial Optical Devices on Backpropagation Learning Capability of Optoelectronic Neural Network
Authors: Ishihara Satoshi , Kasama Nobuyuki , Mori Masahiko , Hayasaki Yoshio , Yatagai Toyohiko
Published: February 2023

Recently there has been a great deal of work on neural network. Offering massive parallelism, high speed, and crosstalk-free interconnection, optical implementation has been sought to fully exploit the parallel characteristics of neural networks(1,2). In those optoelectronic neural networks, "two-dimensionally(2D) extended" and "discretely arrayed" devices, i.e. spatial light devices such as SLMs(spatial light modulators), arrayed light sources and detectors are utilized to enjoy the high parallelism of optics. However, at present it is not easy to obtain such perfect spatial light devices with characteristics satisfying theoretical performance; some have lack of spatial uniformity while others show limited signal-to-noise ratio and so on. Therefore, it is important to investigate the effects of imperfection of spatial optical devices on the system capability of optoelectronic neural network. The influence of interconnection weight discretization and noise in an optoelectronic neural network was reported(3), but only by computer simulation.
Optical Morphological Image Processor
Authors: Lohman Gary E. , Brenner K.-H.
Published: February 2023

Images in the natural sciences often posses distinctive topologies, thus rendering order statistics better suited for image processing than more traditional linear filtering. A useful subclass of order statistics based on binary images is mathematical morphology./1/ Mathematical morphology is also well suited to an optical implementation. /2-5/ Optical mathematical morphology can be performed at a frame rate of 10-100 kHz., thus permitting real-time non-linear image processing in many applications. Our proposed optical architecture also allows for programmable parallel processing of very large images, under control of a small electronic micro-processor.
Optical Implementation of SELECTION Operation in Database Machines
Authors: Athale Ravindra A. , Haney Michael W.
Published: February 2023

In its most elemental form, a database can be viewed as a computer-based record keeping system. The database organization is optimized for efficient addition, deletion and updating of the records. Accurate, flexible and efficient techniques for retrieving and organizing data is the objective of a database management system. Applications of such database management systems range from banking and libraries in the commercial world to onboard electronic warefare systems for airplanes and logistics databases for weapons readiness management in the military world. In either domain, the size of the database is constantly growing, while the desired data retrieval time is simultaneously decreasing. In addition, onboard systems may have volume, power and weight limitations while maintaining ruggedness. The recent developments in optical storage, interconnects and switching technologies has initiated investigation into the use of optical technology to enhance the performance of conventional database machines [1].
Competitive Optical Learning with Winner-Take-All Modulators
Authors: Wagner Kelvin , Slagle Tim
Published: February 2023

Modern neural network learning models such as competitive learning networks[2,4], resonance correlation networks, and back propagation networks[1] require a wider range of neuron behavior than a simple saturating threshold non-linearity. However, optical implementation of neurons that incorporate non-local, non-linear functions such as shunting inhibition, winner-take-all, and history-dependent behavior is beyond the capability of conventional optical devices. A new class of light modulator has been developed that combines the flexibility of analog and digital electronic VLSI circuits, optical detectors, and the switchable electo-optic capabilities of liquid crystal materials. In this paper we will show how these liquid crystal/VLSI modulators can be used in optical implementations of these learning networks. We discuss in detail a competitive optical learning network which uses LC/VLSI winner-take-all neurons on fractal grids to program adaptive volume holographic interconnections. We will present results from tests of the LC/VLSI winner-take-all modulator arrays, and in addition will show preliminary results from an optical competitive learning system that uses the LC/VLSI modulators as neurons.
GaAs-Based Optoelectronic Neurons
Authors: Lin Steven , Ho Francis , Kim Jae , Psaltis Demetri
Published: February 2023

The optical implementation of a neural network consists of two basic components : a 2-D array of neurons and interconnections. Each neuron is a nonlinear processing element that, in its simplest form, produces an output which is the thresholded version of the input. Liquid crystal spatial light modulators are candidates for such 2-D array of neurons. However, they are not flexible in their use. Optoelectronic integrated circuits (OEIC’s), either hybrid, such as liquid crystal on silicon, Si-PLZT, and flip-chip devices, or monolithic integration in III-V compounds, is another solution. In order for these devices to be used as neurons in a practical experiment, they must be large in number (104/cm2–106/cm
2
) and exhibit high gain. This puts a stringent requirement on the electrical power dissipation. Thus, these devices have to be operated at low enough current levels so that the power dissipation on the chip does not exceed the heat-sinking capability, and yet the current levels need to be large enough to be able to produce high gain. This means sensitive input devices are a must. To achieve these goals, the speed requirement of the devices must be relaxed as the operation of neural network does not have to be too fast.
Flexible and fast switching
Authors: Kung H. T.
Published: February 2023

Summary not available.
Extended Generalized Shuffle Networks
Authors: Richards G. W.
Published: February 2023

A successful network architecture generally must consider the technology being proposed for implementation. A design suitable for an electronic application may prove to be unwieldly or even impossible to implement in the photonic domain. Basically this is due to the limitations and constraints imposed by the optical technology at hand.