bluuebunny/crossref_metadata_2025 huggingface dataset:
Narrow-Band Notch Filters produced by Plasma Impulse Chemical Vapour Deposition
Authors: Netterfield R P , Llewellyn Ian
Published: February 2023

There have been several publications in recent years on the use of Plasma Impulse Chemical Vapour Deposition (PICVD) as a means of depositing optical multilayer coatings under computer control [1-4]. We report on the use of the technique in the deposition of notch filters consisting of up to 200 alternating layers of SiO2 and SiOxNy.
Fabrication method for phase mask with spatially variable diffraction efficiency
Authors: Ehbets Peter , Poirier Michel , Lelièvre Sylviane , Shu Collin , Capolla Nadia
Published: February 2023

A phase mask is a phase diffraction grating usually recorded in photoresist and then etched in a bulk substrate as a one-dimensional uniform and periodic surface relief pattern[1,2]. When illuminated at normal incidence with coherent or partially coherent light, the phase mask produces in its near-field self-interference between the first order diffracted beams. This interference fringe pattern will have a spatial frequency that is twice the spatial frequency of the phase mask, and will be photoimprinted in the photosensitive medium placed in close proximity of die phase mask grating. This will generate a uniform periodic modulation of the refractive index acting as a Bragg filter. The Bragg spectral response will then have a narrow-band reflectivity peak at a design wavelength, accompanied by a series of sidelobes at adjacent wavelengths. In today’s global communication, based on wavelength division multiplexing, there is a requirement for Bragg grating with a spectral response having reduced noise and sidelobes to avoid cross talk. Bragg gratings with reduced sidelobes in their spectral response can be generated by recording an index modulation with a spatially varying modulation amplitude[3]. The condition for an efficient sidelobe suppression is that the modulation level decreases continuously to zero at both limits of the Bragg grating. It can be achieved using appropriate apodization profiles[4]. Different approaches have been investigated to realize Bragg gratings that generate a spectral response without sidelobes, with or without the use of a phase mask [5,6,7,8,9]. We propose a new fabrication process leading to improved results in the spectral response of the recorded apodized Bragg grating, suitable for mass production: simplicity, reliability, low cost and short fabrication time.
The Influence of Surface Roughness on The Surface Plasma Wave
Authors: Lee Cheng-Chung , Jen Yi-Jun
Published: February 2023

Optical excitation of surface plasma wave, SPW, in the attenuated-total-reflection, ATR, of the Kretschmann configuration is a very powerful device to obtain optical constants of thin metal films[1,2]. However surface roughness usually influences the results and has two effects: (1) shift the ATR curve(and broaden its half-width) and (2) change the reflection minimum of the ATR curve. Considering a prism-metal film-vacuum configuration as shown in Fig. 1, SPW will be excited when the incident angle of p-polarized light of frequency ω is larger than the critical angle.
Scattering Measurements From A Thin Metallic Film in the Attenuated Total Reflection
Authors: García-Llamas Raúl , Regalado Luis E. , Ramírez-Duverger A. , Monárrez Victor
Published: February 2023

The reflected and transmitted fields scattered from a thin film with a shallow random rough surface between dissimilar media is typically neglected. In an early paper ref. [1], scattering is calculated considering surface plasma waves as a probe, excited in an experimental arrangement known as the Attenuated Total Reflection technique (ATR). In resonant condition forward and backscattering peaks were predicted. In this work, experimental measurement of scattering from this system is reported.
Scatter Investigation of UV-Films: Facing the Trend towards Shorter Wavelengths
Authors: Duparré Angela , Kaiser Norbert
Published: February 2023

Light scattering of optical thin films has been intensely studied for many years /1/, /2/ as it plays a major role in the development of low-loss optical coatings. More recently, with the Atomic Force Microscope (AFM) becoming a useful Instrument for surface characterization, advanced possibilities arose to comprehensively characterize the scatter losses of thin films in the context of microstrucure and roughness /3/,/4/. The increasing demands for high quality coatings in the ultraviolet spectral region, in particular the ongoing trend towards shorter wavelengths with its present focus on 193 nm optics, result in specific challenges for appropriate light scatter investigations.
In Situ Ellipsometric Monitoring of a Dielectric Multilayer Edge Filter
Authors: Drage David J. , Netterfield Roger P.
Published: February 2023

Computer programs have been developed to the stage where they are capable of producing optical thin film designs of 100 layers or more to meet the most demanding performance specification. A measured result of such a design is the edge filter shown in Fig. 1 where a reflectance step from 100% at 680nm to 5% at 666nm is produced.
Shadow Brewster Angles Method for Anisotropic and Weak Absorptive Films
Authors: Surdutovich G.I. , Vitlina RZ. , Baranauskas V.
Published: February 2023

Reflectometric and ellipsometric methods for the measurement of the dielectric permittivity and thickness of a film deposited onto an isotropic substrate with a known dielectric permittivity encounter significant difficulties since the parameters of the film enter into the measured quantities in an involved form. Abelés has shown that the processes of determination of the film’s refractive index and thickness may be completely separated [1]. When the relative reflectances of p - polarized light at the film-covered and uncovered surfaces are equal, the angle of incidence is equal to the Brewster angle of the ambient-film interface. On the other hand, for a film with non-uniform thickness (such as a wedge-shape film or film during the growth process) under variation of the angle of incidence at this “shadow” Brewster angle (where the sample’s reflectance is not equal zero!) the interference fringes of all interference patterns corresponding to the different thicknesses of the film disappear. Moreover, there is another shadow Brewster angle where the sample’s reflectance ceases to depend on the film’s thickness and the interference fringes disappear. Indeed, the intensity reflection coefficient for p - polarized light of an ambient -film - substrate system has the form:
R(θ)=|r01(θ)+r12(θ)e−iδ1+r01(θ)r12(θ)e−iδ|2, where r01, r12 are Fresnel reflection coefficients at ambient - film and film - substrate interfaces,
δ=4πdλε1−sin2θ, d and ε1 are the thickness and dielectric permittivity of the film, λ is the free-space-wavelength and θ is the angle of incidence. Abelés angle (first shadow Brewster angle) θ
B
1 is defined by the relation
r01(θB1)=0. At the point
θB2 where
r12p(θB2) turns to zero (second shadow Brewster angle) the coefficient R, just as in the previous case, does not depend on the film’s thickness. Therefore, the reflectances of films of different thickness (or from different places in the case of a wedge film) will have the same value at the angles
θB1 and
θB2 and so the interference patterns should intersect each other at these points.
Reformulation of Optical Characterization of a Generic Thin Film-Substrate System through the Concept of Envelope-Extrema
Authors: Martinez-Anton Juan Carlos
Published: February 2023

Optical characterization of a deposited material can be done by many experimental and analytical means as is already known [1-2], depending on some factors, like the wavelength range of interest, the thickness, the proper material parameters (n and k), the structure modelization (inhomogeneity, surface rouhgness,..), etc. The presented contribution on optical characterization is related with a new treatment of the common basic formulation. This permits simpler analytical conclusions and explicit formulas for the obtention of optical and dimensional parameters. We will proceed under the context of photometric magnitudes and optical interference coatings, so we can add interferometric information to the analysis.
Common-index thin film polarizers for light at normal incidence
Authors: Hodgkinson Ian , Wu Qi hong , Rawle Chris
Published: February 2023

Linear polarizers, such as the coated beam-splitting cube1, require considerable space in an optical system. In this presentation we describe the design and fabrication of thin film polarizers that can be used with light at normal incidence, and are compatible with existing planar technologies.
Optical characterization of anisotropic plastics
Authors: Hilfiker James N. , Herzinger Craig M. , Bungay Corey L. , Woollam John A. , Elman James F.
Published: February 2023

Plastics have many commercial applications including photographic film and display technology. They often exhibit biaxial anisotropy due to extrusion and stretching during preparation. The characterization of coatings on plastic will improve when the plastic optical properties are understood. Plastic processing can also be monitored through its optical properties.
Bandpass Filter For Forty Five Degree Angle With Low Polarization Properties
Authors: Cushing David
Published: February 2023

Filters for use at 45 degrees made with classical quarter wave stacks and (multiple ) half waves exhibit a large degree of polarization. The P- polarized component has a much wider bandwidth than the S- polarized component. The wavelengths for each polarization are typically not coincident and the average transmission does not yield a suitable passband. Thelen1,2 has suggested methods of reducing polarization that introduce non-quarter wave layers and / or third materials and many layers in order to provide a non-polarizing edge filter. Baumeister3 designed bandpasses with 3 or more materials also. Either of these complications is difficult to deal with. Stress from too many layers and monitoring of non-quarter wave layers are both undesirable. Here it is shown how layers that are multiples of quarter-waves at normal incidence can be used to design filters with very low polarization at severe angles. The polarization for this new design is larger than for the above referenced filter types, but it is much simpler to build.
Characterization of fluence limiting defects in hafnia/silica multilayer coatings manufactured for the National Ignition Facility
Authors: Wu Z. L. , Stolz C. J. , Yoshiyama J. M. , Salleo A.
Published: February 2023

Electron-beam deposition processes are being optimized to improve the laser damage resistance of large aperture (up to 0.34 m2) optical coatings for the National Ignition Facility (NIF). One modification over previous deposition process is the replacement of hafnia as a starting material with hafnium for source ejection reduction.1 This modification has led to a significant reduction (~10 times) in the nodular defect density. Although considerable effort has been spent on studying nodular defects, unfortunately the damage threshold of coatings can also be limited by a multitude of different defect types, i.e. damage sites are also present in nodule-free regions of large aperture optics.
Computer aided design
Authors: Thelen Alfred
Published: February 2023

Examples are the calculation of transmittance, reflectance, and phase as a function of wavelength, sensitivity of thin film structures to thickness and index errors, electrical field calculations, parameters for design models (equivalent indices, effective interfaces, Chebyshev prototypes, Fourier synthesis, etc.), scattering models, etc.
Needle method with simultaneous thickness and refractive index refinement for optical thin film synthesis
Authors: Verly P.G.
Published: February 2023

The Needle method is currently one of the most powerful thin film design techniques. It exists in several versions described in the literature or implemented in thin film design programs.1,2,3 This technique is an application to thin film design of some of the principles of optimal control theory. Thin layers of suitable refractive indices are inserted in a multilayer system, in appropriate positions, when no further progress be made by conventional refinement. Refinement of the modified system results in a better solution. The optimum needle positions are found by evaluating a perturbation function, which can be analytical or purely numerical. The analytical approach is more accurate and faster, while the numerical one is more flexible. Some implementations of the needle method use sophisticated second order optimization algorithms.
Automatic design of multilayer optical coatings
Authors: Noe Tony D.
Published: February 2023

With the advent of high-speed personal computers and modern algorithms, it is possible for the designer to create a wide variety of coating designs automatically. This capability is important because, in many cases, the designer may not have the time and resources to craft a design manually. For unusual designs, where there may be little or no theory to use as a guide, automatic design is indispensable.
An expression for the halfwidth of phase dispersion induced transmission filters
Authors: Zheng Shu-ying , Guo Ping
Published: February 2023

The theory on induced transmission in absorbing thin films1,2 made it feasible to design dielectric-metal narrow band filters based on the relationship between the optical properties and the optical surroundings of a metal layer. It has been indicated that narrow band reflection and transmission of a metal layer may be induced by a drastic change in the reflection phase shift from the matching stack attached to the emergent boundary of the metal layer3 and that the halfwidth of spectral band was inversely proportional to the phase dispersion power4. It can be seen in this paper that a simple expression for the halfwidth of phase dispersion induced transmission (PDIT) filters was a derivative of the induced transmission theory.
Analytical achromatic design of metal-dielectric absorbers
Authors: Lemarquis F. , Marchand G.
Published: February 2023

Broad band absorbers are key components to suppress parasitic light, especially for spatial applications. This optical function is usually fulfilled by rough black surfaces or paints, that can be dielectric coated for better performances [1]. However in this case the non absorbed light is fully scattered, what cannot be accepted for some applications [2]. Therefore smooth metal-dielectric coatings may provide efficient alternative solutions to these problems.
Quantum Well Optical Modulators and Self Electro-optic Effect Devices (SEED's)
Authors: Miller D A B , Chemla D S , Damen T C , Wood T H , Burrus C A , Gossard A C , Wieqmann W
Published: February 2023

We present a new family of electro-optic devices based on the unique room-temperature optical properties of GaAs Multiple Quantum Well Structures (MQWS)(1-4). We demonstrated high-speed modulators(3,5), and a set of so-called "Self Electro-optic Effect Devices" (SEED's)(6) using internal optoelectronic feedback: a mirrorless optically-bistable switch(6) with very low switching energy, a self-linearized modulator(7) and an optical level shifter(7).
Formation of Single-Mode Waveguide Microlenses and Microlens Arrays Using Titanium Indiffused Proton Exchange Technique in LiNbO 3 *
Authors: Zang D. Y. , Tsai C. S.
Published: February 2023

Lenses are among the key components in optical signal processing and computing systems(1). Realization of such optical systems in a waveguide substrate has long been considered one of the major applications of integrated optics. Recently, the prospects for this realization are significantly advanced through progress in guided-wave microoptic components of both active and passive types. Aside from the study on integrated acoustooptic RF spectrum analyzers(2) that has become an international effort, serious attempts to utilize the integrated optic devices for optical computation of both analog and digital data are also being made at various research institutions. Accordingly, it is of great importance to develop viable techniques for fabrication of waveguide lenses with application to optical computing. A variety of planar waveguide lenses including the geodesic, chirp-grating, Fresnel, and Luneburg types have been reported in the literature. A common characteristic of these lenses is a relatively long focal length and a relatively small numerical aperture. It is to be noted that a channel waveguide lens involving multiple coupled-waveguides has also been proposed most recently(3). In this paper we report on the single-mode planar waveguide microlenses and microlens arrays in LiNbO3 that are formed using titanium indiffused-proton exchange technique(4). These waveguide lenses have demonstrated desirable properties including very short focal length, large numerical aperture, very small focal spot size for a wide range of focal length, and low optical insertion loss at the 6328 Å He-Ne laser wavelength.
Application of Optical Fiber Image Guide to an Optical Feedback System*
Authors: Griffith Paul C. , Collins Stuart A.
Published: February 2023

This paper deals with the design of numerical optical computing systems using a liquid crystal light valve (LCLV) as the active element. In particular the innovation of optical image guides as information transmission agents is considered. In the past optical logic gates (Fatehi, 1981) and flip-flops(Gerlach, 1980) have been demonstrated along with coupled sequential circuits (Cheval, 1983). These have used lenses and mirrors as the information transmission agents and holograms for information routing. Image guides can have an information carrying capacity at least equal to that of simple lenses, and with much higher energy collection and transmission capability. There is also an ease of alignment afforded by flexible image guides.
Multi-channel Bragg Cells for Optical Systolic Matrix Processing
Authors: Pape Dennis R.
Published: February 2023

The promise of optical information processing is a general purpose optical computer capable of programmable parallel operation on a large two-dimensional data field. The lack of high performance two-dimensional spatial light modulators (SLMs)(1), however, has hindered this development. Recently, systolic matrix architectures(2) have been suggested as a means of rapidly and efficiently processing two-dimensional data. The optical implementation of these architectures requires a high performance SLM with the property that data can be serially transferred without loss across the modulator. The multi-channel acousto-optic Bragg cell is an ideal SLM for realizing two-dimensional optical systolic parallel matrix processing.
Fabrication and Testing of a Space and Frequency-Multiplexed Optical Linear Algebra Processor
Authors: Casasent David
Published: February 2023

Optical linear algebra processors (OLAPs) represent a most flexible and general-purpose class of optical system. In Section 2, we describe the architecture for a space and frequency-multiplexed OLAP. We detail (Section 2) how this system accommodates bipolar and complex-valued data and its use in matrix-vector processing. The electronic support system is described in Section 3. The optical system and initial experimental results obtained on it are detailed in Section 4.
Digital Optical Multiplication by Color Multiplexing
Authors: Patkar Niteen A. , Krile Thomas F. , Walkup John F.
Published: February 2023

A system is described which performs the multiplication of two binary numbers in a highly parallel fashion. The number of output levels is kept to a maximum of three. The required logical AND operation is performed using a 2-bits-at-a-time approach. A scheme is also presented for performing the conversion of mixed binary numbers to binary numbers. As the maximum number of output levels is restricted to three, the system's noise immunity is high.
Why use the Parallelism of Optics?
Authors: Huang Alan
Published: February 2023

The fundamental advantage which optics has is its parallel communications capability. Lenses, mirrors, and prisms can easily communicate millions of wide bandwidth channels in parallel. The question arises as to how to take advantage of this capability. This difficulty is more a computer science problem than an optics problem. Large arrays of processors have yet to be built and successfully applied. The two basic approaches being pursued involve either a single instruction multiple data (SIMD) or a multiple instruction multiple data (MIMD) architecture. The single instruction multiple data architecture is the most prevalent version since it is simpler conceptually, however it is limited in terms of application and difficult to use. The more interesting architecture is the multiple instruction and multiple data configuration. The main difficulty in applying this architecture is finding a means of coordinating the various asynchronous processes. This need for coordination brings alone with it a large communications burden. The classification of parallel processors into SIMD and MIMD processors is formal and only hints at how the parallel communications capability of optics might be used.
A study of scattering from small structures for optical beam shaping and interconnects
Authors: Lightbody M.T. , Fiddy M.A.
Published: February 2023

Optics is attractive for computing because of its distinct advantages over electronics, in particular the inherent non-interaction of multiple beams passing through, or near, each other and the potentially massive parallelism. In order to compete with electronics these two properties should be fully exploited. Therefore it is of importance to consider what fundamental limitations will apply to the density of optical sources, or secondary sources, in terms of the acceptable levels of cross talk that will occur in an adjacent array of detecting elements. In order to beat electronics the dimensions of each decision making plane must be kept as small as possible. The physical consequences of this necessity must be well understood before such questions as optimal architectural structure can be addressed.
A 2-D Clos Optical Interconnection Network
Authors: Lin Shing-Hong , Krile Thomas. F. , Walkup John. F.
Published: February 2023

An important aspect in the design of a 2-D parallel processor is efficient interconnections. Crossbar networks(CBN) are considered to be the most desirable candidates because every processor can communicate with every other processor without conflicts. Implementing a large 2-D CBN, however, is very difficult[1]. A Clos network(CN)[2], Clos(p,q,r), as shown in Fig. 1 is proposed to replace the CBN. In Fig. 1, each block represents a feasible subcrossbar of medium size. The CN has the same characteristics as the CBN. The CN is a nonblocking network with which it is always possible to connect together an idle input-output pair of processors without disturbing existing connections, if q≥2p-1 is satisfied. Both one-to-one and one-to-many connections are available in the CN. The most important factor is that the number of switching elements has been reduced in the CN(~10:1 for a 1000x1000 network, as compared with the CBN). The difficulty of determining connections, however, is a major problem to be overcome[3,4].
Optical Implementation of Min and Max Operation
Authors: Yang Hedong , Guest Clark C.
Published: February 2023

In fuzzy logic [1,2] and fuzzy cognitive maps (FCM) [3-5], the operations of maximum and minimum play roles that are parallel to those played by addition and multiplication in ordinary matrix algebra. For example, in a fuzzy associative memory (FAM) [6], the connection matrix is constructed by taking the outer product of the vector to be memorized with min operation substituting for product of elements, i.e, tij = min (ai, aj).
Digital Optical Processor Based on Symbolic Substitution Using Matched Filtering
Authors: Jeon Ho-In
Published: February 2023

In this paper, we propose a digital optical processor design based on symbolic substitution using holographic matched filtering and space-invariant interconnections. The proposed system performs binary addition in a highly parallel manner, i.e., the processing time depends on the word size but not on the array size. Crosstalk in symbolic substitution is described and new symbols which can prevent crosstalk in binary addition are introduced.
Optical Neural Nets Implemented with Volume Holograms
Authors: Psaltis Demetri , Yu Jeffrey , Gu Xiang Guang , Lee Hyuk
Published: February 2023

An optical implementation of a neural net computer consists of two basic components: neurons and connections. The neurons are simple nonlinear processing elements (e.g. thresholding units) that accept inputs from other neurons and produce a single output that is broadcast to many other neurons. Typically we think of each neuron being connected to thousands others. Hence the number of connections in a network is much larger than the number of neurons. This simple fact is the principal motivation for considering optical implementations of neural nets [1]. The basic approach we have adopted is shown in Fig. 1. The neurons are arranged in a planar configuration and interconnected with optical elements (holograms or masks). Several emerging optical technologies can be considered for the implementation of the two basic components. We have come to the conclusion that the most promising technology for the implementation of neurons is optoelectronics; a two dimensional array of LEDs, a detector adjacent to each LED and a saturating amplifier connecting the two [2,3]. We are considering two possiblities for performing the connections: optical memory disks and volume holograms [2]. In this paper we examine the advantages of using volume holograms as opposed to planar media for storing the interconnect pattern, we present methods for achieving different types of arbitary global interconnections, and we present experimental results using a photerefractive crystal (LiNbO3) to implement modifiable synapses.
Analog Complexity Theory †
Authors: Steiglitz Kenneth
Published: February 2023

Digital computing algorithms are analyzed using a simple and abstract model for computation: the Turing Machine, or close equivalents. The simplicity of the model makes it possible to measure complexity in terms of only two resources — time and space, and allows us to use asymptotics without concern for noise or the breakdown of physical laws. Analyzing the complexity of analog computation is more difficult because of the modeling problem, and the theory and technique are at an earlier stage of development. In this talk we will discuss this theory, and give some examples of its application. Much of the discussion is based on [1].
Real-Time Acousto-Optic Spot-Light Mode SAR Processor
Authors: Haney Michael , Psaltis Demetri
Published: February 2023

High-resolution imaging with the Synthetic Aperture Radar (SAR) technique is widely recognized as the most successful application of optical information processing to date. Optical signal processing (OSP) techniques have been applied to the collection and processing of SAR data since the introduction of the technique over thirty years ago. Despite this success the use of optical techniques for real-time SAR applications has generally been precluded by the need for chemical processing of the film on which the radar data are recorded. Consequently, and in concert with the dramatic successes in integrated circuit technology, most existing real-time SAR processors are based on electronic signal processing techniques. Recent advances in optical transducer technology, however, have given rise to renewed interest in real-time optical SAR. Specifically, a time-and-space integrating (TSI) architecture has been developed that uses acousto-optic (AO) Bragg cells and charge-coupled device (CCD) detector arrays to generate SAR images at real-time rates [1]. This architecture compares favorably with the all-electronic approaches in the areas of speed, size, power consumption, and EMI/EMP immunity. Recent developments in the TSI architecture have incorporated electronic programmability and flexibility to expand the realm of practical application of the approach [2,3].
A Highly Cascadable Optically Bistable Device for Large Fan-out Optical Computing Applications
Authors: Craft N.C. , Smith S.D.
Published: February 2023

Smith et al have shown (1) that in order to ensure that the change in output from one bistable device is sufficient to switch the succeeding one, the technique know as ’hold and switch’ is desirable. This involves holding a device as close as possible to its switch point with one laser beam, and using the change in output from a previous similar device to induce switching, thus providing fully restoring logic. Due to the fact that the holding power cannot be made arbitrarily close to the switching power, and that a substantial "over switch" is required to avoid the effects of critical slowing down, there exists a fundamental limit upon the cascadability and fan out potential of conventional bistable devices. This is because their change in output power can only be less than or equal to their switching power. A better device would be one in which the change in output power could be significantly larger than the switching power. The twin cavity device (TCD) described here will be shown to possess this quality.
Optimum Control Beam Angle for a Biased Fabry-Perot Bistable Device
Authors: Cush R. , Bennion I.
Published: February 2023

The use of bistable Fabry-Perot devices as multi-port cascadable devices has been frequently discussed in the literature (1-3). It has been envisaged that such devices could be addressed by a number of bias and control beams each approaching the device at a different angle (fig. 1). However, if these devices are to be cascadable, the same wavelength of light must be used for all control and bias beams. In this situation the control beam intensities inside the devices will be determined by the amplification effects of the cavity. Their behaviour will differ from that of the bias beam as the different incident angles produce additional phase changes. It has been shown that these additional phase changes give rise to bistable switching as the incident angle of the beam is changed (4) and this behaviour is demonstrated experimentally.
Variable-Gamma Spatial Light Modulator
Authors: Lau Suzanne , Warde Cardinal
Published: February 2023

A high-resolution, optically-addressed, variable-gamma spatial light modulator would be very useful for general-purpose, real-time optical processing. In this paper, we describe how the standard and Fabry-Perot Microchannel Spatial Light Modulators (MSLM)1-3 can be modified and operated to achieve a wide range of gamma similar to that for phototgraphic emulsions (see Fig. 1). Such a variable-gamma device will be applicable to both linear (low gamma) and nonlinear (high gamma) optical processing. Preliminary image processing results are presented.
Passive Single-Mode Optical Networks for Coherent Processing
Authors: Marhic M. E.
Published: February 2023

We consider in this paper optical networks made entirely of passive single-mode interconnection components. These can be lengths of fiber, or integrated optic waveguides, in which the same kind of single mode propagates. These individual modes can also be added/divided by means of directional couplers interconnecting the waveguides. [Similar networks could also be considered, making use of free-space Gaussian beams and beam-splitters; this however, would introduce difficulties due to alignment and diffraction.] We refer to the resulting architectures as passive single-mode optical networks.
Multiple Polarization State Threshold Logic and Processor
Authors: Wu Shudong , Zhang Xiang , Wang Zhijiang
Published: February 2023

This paper suggests a novel technique of using multiple polarization states to implement different logic operations in parallel. Sophisticated full optical A/D converter, look-ahead adder and multiplier are proposed.
Interferometric Pattern Encoding for Parallel Logic Operation
Authors: Ikeda Makoto , Yatagai Toyohiko , Ishihara Satoshi , Mitsuhashi Yoshinobu , Kaya Junichi
Published: February 2023

Recently, some optical parallel pattern logic operations have been proposed(1-2). In order to implement these techniques, binary input data represented in transparent or opaque pixels must be spatially encoded. Tanida and Ichioka have described the method of spatial encoding technique(3) based on a holographic EXCLUSIVE-OR (XOR) operation for their parallel logic operation.
Infrared Pre-Detection Dynamic Range Compression Via Photorefractive Crystals
Authors: Liu Hua-Kuang , Cheng Li-Jen
Published: February 2023

Pre-detection infrared dynamic range compression concept via the nonlinear photorefractive two-wave mixing in GaAs crystals will be discussed. Some experimental results will also be presented to support this idea.
64 Element Hybrid PLZT/Silicon Spatial Light Modulator Array
Authors: Bennion I , Goodwin M J , Groves-Kirkby C J , Parsons A D
Published: February 2023

The high-throughput spatial light modulator (SLM) is a key component in an expanding range of optical signal processing applications and VLSI interconnect scenarios. With the continuing trend towards overall system integration, a number of approaches have been pursued in recent years, with the common aim of developing a silicon-compatible modulator system, preferably addressed via a fully integrated silicon back-plane with a 1:1 mapping between drive circuits and modulation elements. Potentially viable technologies investigated hitherto include liquid crystals [1,2,3], magneto optic materials.[4] and micromechanical devices fabricated in silicon itself [5], all of which exhibit relatively limited modulation rates.
Optical Nonlinear Neurons and Dynamic Interconnections Using the Field Shielding Nonlinearity in CdTe
Authors: Steier William H. , Ziari Mehrdad
Published: February 2023

An optical neuron and a high density dynamic optical interconnect are two of the critical elements in the realization of an optical neural net computer. The key to both elements is an optical nonlinear material with a sufficiently large nonlinearity at reasonable optical intensities which can be used at wavelengths compatible to integration with semiconductor sources and detectors. The field shielding nonlinearity in semiconductors such as CdTe is a charge transfer effect wherein an optical beam creates photocharge which then alters the electric field pattern in the material1. The change in electric field through the electrooptic effect can then be used to create a dynamic optical interconnect or a nonlinear neuron. In semiconductors this effect can have a formation time on the order of microseconds, has a relatively low required intensity on the order of tens of microwatts per cm2, and can be used in the infrared. CdTe is a particularly promising material since its figure of merit, n3r/ε, which is a measure of the index change per absorbed photon, is relatively large2.
Design of a Symbolic Substitution Based, Optical Random Access Memory
Authors: Murdocca M. J. , Sugla B.
Published: February 2023

Symbolic substitution is applied to the design of an optical random access memory. The design is near-optimal in gate count and circuit depth.
Parallel Addition and Subtraction in One Computing Cycle Using Optical Symbolic Substitution
Authors: Pedrini G. , Thalmann R. , Weible K. J.
Published: February 2023

The mass parallelism offered by optical interconnection networks is exploited in the construction of optical parallel processors. Optical symbolic substitution is one form of parallel processing, which uses only space-invariant interconnections. It performs the search and replace for a set of specified spatial patterns in parallel upon an entire input matrix.1 Symbolic substitution systems are being proposed for application in areas such as image processing or digital arithmetics, where it is desired to have a large data base operated on in parallel.
Operating constraints of a light valve as a 2-D accumulating buffer for optical cellular processors
Authors: Wang J.M. , Taboury J. , Chavel P.
Published: February 2023

Optical cellular processors such as the well known symbolic substitution processors require in all cases some kind of a 2-D buffer memory to store the binary result of each iteration. At the next iteration, the memory is read and fed back to the data input plane. In addition, algorithms involving a sequence of more than one binary image recognition per iteration also require the buffer memory to operate as an accumulator storing the results of the successive steps.
An All-Optical Programmable Logic Gate
Authors: Craig R.G.A. , Buller G.S. , Tooley F.A.P. , Ichikawa H. , Smith S.D. , Walker A.C. , Wherrett B.S.
Published: February 2023

Experimental results are presented showing all-optical programmability and operation of a multi-function Boolean logic circuit. All eight symmetric two input logic functions have been demonstrated. Comments on the practical implementation and usage of this circuit are made.
Energy Efficiency of Optical Interconnection Using Photorefractive Dynamic Holograms
Authors: Chiou Arthur , Yeh Pochi
Published: February 2023

Reconfigurable optical interconnection [1] linking laser arrays and detector arrays plays a key role in optical computing. A generalized crossbar switch [2] allowing arbitrary interconnection, including many-to-one and one-to-many (broadcasting), is the most desirable type of interconnection network for parallel processing. Such a switch can be implemented using optical matrix-vector inner product architecture [3] where a spatial light modulator (SLM) can be used as a binary matrix mask for configuring the interconnection pattern. For one-to-one interconnection (permutation) of a linear array of N-sources to a linear array of N-detectors (i.e., a normal crossbar), the upper limit of the energy efficiency of such an architecture is 1/N due to its fanout nature. Recently, we have proposed and demonstrated [4,5] that photorefractive dynamic holograms can be incorporated into this architecture to significantly improve the energy efficiency. In this paper, we report experimental results on the energy efficiency of such a reconfigurable interconnection using a BaTiO3 crystal.
Microoptic Systems: Essential for Optical Computing
Authors: Jewell J.L. , McCall S.L.
Published: February 2023

The history of information processing has seen a continuing trend toward ever-smaller devices and systems. Optics, well-suited for long distance communication, is currently the focus of many efforts to revolutionize computer technology, however many obstacles need to be dealt with realistically in order for it to have a chance of succeeding. Heat dissipation has long been thought to be a "fundamental" roadblock to optical computing. For any given architecture, minimization of propagation delay times is essential in the design of fast computers1. Architectural flexibility and manufacturability are additional issues which could potentially prevent optical computing systems from entering the marketplace. To overcome all of these hurdles it is necessary to develop microoptical systems far smaller2 than those generally envisioned in the literature, either in the form of integrated optics1 or microlenses and arrays. Here we address the latter approach and review some technological progress.
Optical Holographic Interconnection Networks for Parallel and Distributed Processing
Authors: Lin Freddie
Published: February 2023

With the rapid advances in technology, it is now feasible to build a system consisting of hundreds or thousands of processors [1-3]. Processors in such a parallel/distributed system may spend a considerable amount of time just communicating among themselves unless an efficient and fast interconnection network connects them. The first method for realizing optical interconnections that comes to mind is by means of optical fibers. However, optical fibers are not necessarily the ideal solution for large-scale multicomputer systems, since it requires a physical path for the interconnection between every two processors, and rather inflexible path at that.
Techniques for Array Illumination
Authors: Streibl Norbert , Jahns Jürgen
Published: February 2023

In an optical computing system comprising free-space interconnections the uniform illumination of two-dimensional arrays of nonlinear devices is a crucial task. Various techniques using Fraunhofer diffraction, Fresnel diffraction and spatial filtering are compared.
Array Illuminator Using Grating Couplers
Authors: Takeda Mitsuo , Kubota Toshihiro
Published: February 2023

Several schemes have been proposed for implementing array illuminators,1-4) which are used to distribute optical power to an array of optical logic gates or bistable devices that require optical power supplies. The schemes reported so far are based on assembling bulk optical elements such as Damman gratings1) or lenslet arrays3). In these schemes, relatively large spaces between optical elements (and between optical elements and devices, as well) constitute an essential part of the illuminating system because optical power is distributed by propagating light through these spaces. The system, therefore, tends to lack compactness, and alignments and stabilities of the total system may become a critical issue as the system grows complex. To solve these problems, we take an alternative approach based on integrated optics. In this paper, we propose to use grating couplers5),6) to generate an array of many beamlets.
Hybrid Acoustooptic Spectrum Analyser for Radioastronomy with Semiconductor Lasers
Authors: Evtihiev N. N. , Perepelitsa V. V. , Esepkina N. A. , Pruss-Zhukovsky S. V. , Vlasov O. N. , Kruglov S. K.
Published: February 2023

Acoustooptic processors are mostly long-term devices for real time signal analysis and for modern optical parallel computers. Their merits are evident in the field of radioinformation, for instance in radioastronomy. But the realization of the whole cycle processing with the demands of high output SNR, high reliability and stability of the results of computation can be possible only in a hybrid optoelectronic processor with the controlled semiconductor laser. These lasers broaden the field of application of optical processors that includes the one pulse analysis of high rate processes, gives the opportunity to recieve compact and high stable devices.
Cascade Connective Optical Logic Processor Using 2-Dimensional Electro-Photonic Devices
Authors: Kawai S. , Tashiro Y. , Ichinose H. , Kasahara K. , Kubota K.
Published: February 2023

Various approaches to achieve digital optical processing have been proposed[1]-[3]. In order to achieve general processing, it is necessary to execute various kinds of logic operations. Moreover, individual processors must be connected each other. Few processors, however, have been previously reported with data representation suitable for cascade connection. Most of the processors proposed so far require pre-coding process, which makes hardwares complicated. If optical output signals from a processor are to be used as optical input signals for a next stage processor, pre-coding process is not necessary, which results in the realization of cascade connectable processing systems.
Optical Disk based Correlation Architectures
Authors: Psaltis Demetri , Neifeld Mark A. , Yamamura Alan
Published: February 2023

In this paper we describe and experimentally demonstrate optical image correlators that are implemented using optical memory disks. Optical correlation for pattern recognition [1] has long been considered a promising application for optical processing. One of the reasons such correlators have not been used in practical applications yet has been the lack of suitable spatial light modulators to be used as real time input devices. Recently, this limitation has to a large extent been removed through the development of a variety of 2-D SLM’s [2] and concepts that allow the utilization of mature 1-D (acoustooptic) SLM’s [3]. Attention has therefore shifted to the design of appropriate filters to perform reliable recognition [4]. In most practical applications a single filter is not suffiicient to produce reliable recognition, and the use of spatial [5] and temporal [3] multiplexing to search through a library of filters emerges as the most straightforward solution to the problem. The optical disk correlator architectures we describe in this paper provide an extremely efficient method for performing this task since they combine in a single device the huge memory required for storage of the library of reference images, the spatial light modulator needed to represent the reference in the optical correlator, and the scanning mechanism to temporally search through the library.
Proposal for an Optical Content Addressable Memory
Authors: Murdocca Miles , Hall John , Levy Saul , Smith Donald
Published: February 2023

A content addressable memory (CAM) design that demands high throughput is proposed for arrays of optically nonlinear logic gates interconnected in free space.
Integrated Optoelectronic Cellular Array For Fine-Grained Parallel Processing Systems
Authors: Hibbs-Brenner M. , Mukherjee S.D. , Bendett M.P. , Tanguay A.R.
Published: February 2023

Due to the limitations of electrical interconnections, and the lack of compact optical logic elements, it may be advantageous to implement architectures requiring a high degree of parallelism and interconnectivity with a hybrid system which utilizes the massive interconnection potential of optics, while performing logic functions in electronics. This paper describes the development of an AlGaAs/GaAs based integrated optoelectronic cellular array (IOCA) in which each cell consists of an electronic processing element together with optoelectronic devices which perform the I/O function. Topics to be discussed in this paper include: potential applications of the IOCA, limits to scalability of the array, the choice of the optoelectronic components utilized in the chip, and the fabrication of integrable optoelectronic devices.
Optical Error Correction by Adaptive Thresholding
Authors: Kagan David , Friedmann Harry
Published: February 2023

During the last few years we have suggested1−2 the use of a four-level system irradiated by a bichromatic beam to obtain a tunable optical bistable device. By tunable we mean that the switching threshold can be altered without changing the hardware characteristics, the operating temperature, or the frequencies of the inputs to the device. The basic principle of our suggestion is that by irradiating the non-linear optical material by two beams of appropriately chosen frequencies in an optical cavity, one can act as a signal and the other as tuning control beam. The advantage of the four level system lay in the possibility of using low power control beams which could tune the characteristic optically bistable output curves.
Optical Multiple-valued Logic Using Composite Bistable Laser Diode or Light Emitting Diode Circuits
Authors: Liu Shutian , Li Chunfei , Wu Jie , Liu Yudong
Published: February 2023

Multiple-valued logic offers many times the logic power and packing desity of binary logic, thus reducing the number of necessary logic gates.1 Recently optical multip1e-va1ued logic has been studied extensively using shadow casting method.2 In this paper we describe a new configuration of optical multiple-valued logic gates using composite bistable laser diode or light emitting diode circuits (BILD or BILED). To our knowledge, this is the first time that optical multip1e-va1ued logic have been obtained using optical bistable device. We have demonstrated four Post logic functions: Complement, Max(x,y), Min(x.y), and Suc(x) using composite BILED circuits. We only take Complement and Max(x,y) for example here.