bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Possibility of Real Time Transmission of Images in Multimode Fibers
Authors: Gover A. , Lee C. P. , Yariv A.
Published: February 2023

Multimode dielectric waveguides cannot transmit pictorial information over substantial distances. The most fundamental reason for this failure is modal dispersion, i.e., the dependence of the propagation constant of the mode (m,n) on the transverse mode indices m,n.
Low-Loss GaAs p+-n−-n+ Optical Striplines Fabricated Using Be+-Ion Implantation*
Authors: Leonberger F. J. , Donnelly J. P. , Bozler C. O.
Published: February 2023

The development of GaAs-based integrated optical circuits (IOCs) requires low-loss three-dimensional waveguides to transmit and confine the optical signal to specific locations on a chip, and also to fabricate various optical components. In this paper, we report the successful fabrication of single-mode p+-n−-n+ optical striplines. These striplines have exhibited low loss (a ≈1. 2 cm-1 at 1.06 μm), and the p+ -n− junctions have shown sharp breakdown voltages corresponding to average electric fields in the n− guiding layer of 2 x 105 V/cm. This suggests the feasibility of developing GaAs modulators, directional couplers and optical switches having lower loss than those reported previously.
Low Loss AlxGa1-xAs Waveguides Grown by Molecular Beam Epitaxy
Authors: Merz J. L. , Cho A. Y.
Published: February 2023

Optical losses in dielectric waveguides constitute a serious limiting factor on their performance in optical devices. In particular, losses in the ternary compound AlxGa1-xAs are important because (a) low threshold GaAs double heterostructure (DH) lasers utilize a very narrow active region (~0.2 μm) with low optical confinement, so that a significant fraction of the optical energy is in the AlxGa1-xAs cladding region where there is no gain, and (b) the larger band-gap of AlxGa1-xAs makes this material an attractive candidate for passive interconnections between active GaAs devices in integrated optical circuits. Recently, attention has been focused on GaAs layer growth by molecular beam epitaxy (MBE) for the fabrication of lasers and other optical devices because of the inherent advantages of MBE for layer uniformity and thickness control. In this paper, it is demonstrated for the first time that Al.1Ga.9As waveguides can be fabricated by MBE with below-band-gap losses comparable to or less than the losses observed in similar waveguide structures grown by liquid phase epitaxy (LPE).
The Growth of LiNbO3 Thin Films by Liquid Phase Epitaxy
Authors: Ballman A. A. , Tien P. K.
Published: February 2023

The need for active materials suitable for optical waveguiding devices has stimulated work on the growth of LiNbO3. Thin films of this important ferroelectric material have been grown by a variety of techniques which include, diffusion processes, epitaxial growth by melting and more recently, liquid phase epitaxy.1-7
A Movie on the Melt-Phase Epitaxial Growth of LiNbO3 on LiTaO3 Substrate
Authors: Ballman A. A. , Brown H. , Tien P. K.
Published: February 2023

The method of epitaxial growth by melting was first applied by Ballman1 to grow 6Bi2O3:1TiO2 on Bi12GeO20. It was later used by Miyazawa2 and by Ballman and Tien3 for growing single-crystal LiNbO3 waveguides on LiTaO3 substrates. The method has since earned a special position in integrated optics on the following accounts: First, for the method to apply the material used for the film must have a melting point lower than that for the substrate. It turns out that the material which has a lower melting point has also a larger refractive index. Therefore, the condition of waveguiding that requires the film to have a refractive index larger than the substrate is automatically satisfied. Secondly, the film grown by this method has a broad transition region in which the material varies slowly from the film composition to the substrate composition. The transition minimizes any effect due to mismatch in lattice between the film and the substrate. Finally, the refractive-index profile of the film follows roughly a Fermi function which is somewhere between the step function of the uniform waveguides and the exponential function of the diffused waveguides. There appears to be no difficulty in forming a single-mode waveguide.
Application of Integral Optics to Chemical Spectroscopy
Authors: Swalen J. D. , Fischer J. , Santo R. , Tacke M.
Published: February 2023

We have measured the absorption spectra of a monolayer of a cyanine dye and a substituted stilbene by the attenuation of an optical wave in a thin film sandwich of sputtered glass and polyvinyl alcohol. Fluorescense along the track was also seen. Sensitivity for absorption has been shown to be higher by almost four orders of magnitude over the conventional s and p spectroscopic methods1 making accessible and feasible studies of molecular devices with thin films of organic molecules.
Absorption Spectroscopy of Scattering Samples Using Integrated Optics
Authors: Mitchell Gordon L. , Harris Jay H.
Published: February 2023

Transmission absorption spectroscopy is commonly used to determine the concentration of chemicals that absorb light. A familiar qualitative example of this powerful analytical technique is looking into a cup of coffee to determine its "strength". The technique can be applied to determine the concentration of an absorbing material in a clear nonabsorbing solvent.
Embedded GaAs-GaAlAs Heterostructure Lasers
Authors: Lee C. P. , Samid I. , Gover A. , Yariv A.
Published: February 2023

Multilayer GaAs-GaAlAs thin film structures are used extensively in optical electronics and are of considerable promise for integrated optics. Although planar technology has long been used in electronic integrated circuit industry, it is only in its initial development stage in monolithic integrated optics. Selective diffusion(1,2), etching(3,4) and proton bombardment(3,5) for fabricating stripe geometry lasers and waveguides have been reported.
Single-Transverse-Mode Injection Lasers with Embedded Stripe Layer Grown by Molecular beam Epitaxy
Authors: Lee T. P. , Cho A. Y.
Published: February 2023

In order to achieve efficient coupling of the light output from an injection laser into a low-loss single-mode optical fiber, single transverse-mode operation of the laser is essential. Past efforts have been directed toward lateral current confinement by use of stripe contact(1), mesa structure(2) and diffusion-isolation methods(3). More recently, the feasibility of forming optical-waveguide(4) in the plane of the junction by LPE techniques has been explored, and lasers operated single-mode were demonstrated up to twice the threshold current. In this work we report single transverse-mode operation of a laser with an embedded stripe grown by molecular beam epitaxy. The superior lateral confinement of injected current enabled the laser to operate in a single mode up to six times threshold.
Parallel End-Butt Coupling of a GaAs Laser Diode and a Thin Film Waveguide
Authors: Hunsperger R. G. , Lee A.
Published: February 2023

Efficient coupling of an injection laser diode to a thin film optical waveguide is difficult to achieve by using prism, grating, or tapered film couplers such as those generally used with gas lasers. The reason for this is that the injection laser has a relatively uncollimated emitted beam which diverges at a half angle of typically 10 to 20°. Prism, grating, and tapered film couplers are all very sensitive to the angle of incidence of the light beam, requiring collimation to better than 1° for efficient coupling. A more promising approach is to use the direct end-butt coupling scheme diagramed in Figure 1.
Automated Analysis of Schmidt Photographs
Authors: Kibblewhite E.J. , Bridgeland M.T. , Bunclark P.S. , Irwin M.J.
Published: February 2023

A single photograph taken on the 48 Inch Schmidt at Palomar records 2 billion pixels of information, over 3000 times more data than is produced by a large format CCD frame. Analysis of this data requires the development of a very high speed accurate microdensitometer, adequate computing facilities to measure the properties of the images on the photograph, and software to handle the large data base which can, for instance, classify the various types of images, collate data taken on a large number of photographs of the same area of sky, extract objects of special interest from the data set.
Application of a Fast Monte-Carlo Algorithm to the Problem of Photometry in Crowded Fields: CCD Data of NGC 121
Authors: Wamsteker W. , Driessen C.
Published: February 2023

The availability of large size linear detectors for astronomical research requires new approaches to the data analysis. The problems are two-fold (A) large information content and (B) the high speed of such detectors allows a rapid building up of untreated information. We describe here the results obtained by a Monte-Carlo Method, based upon a well defined knowledge of the point spread function. The method is used to derive 2-color (B, V) photometry in the magellanic cloud cluster NGC 121. The results are shown and the usefullness of the method is discussed.
The Reduction of Large-Format, Crowded-Field Stellar Photometry
Authors: Newell E. B. , Harding Paul
Published: February 2023

The quality of the information that is derived from two-dimensional astronomical images depends in a complex way on (i) the characteristics of the field imaged, (ii) the effect of the intervening medium, (iii) the properties of the telescope/detector combination, and (iv) the properties of the reduction methods. Clearly, the above factors are listed in order of increasing susceptibility to control; the most accessible route to better measurement is via better reduction methods. It follows that the first step in any attempt to design optimal observing procedures must be to ensure that the reduction algorithms employed can extract the maximum amount of information from the observational data.
Pattern Recognition in Large Format Images Based on 2-D Fast Fourier Transforms
Authors: Glackin David L.
Published: February 2023

We have developed a technique for pattern recognition in large-format images based on the use of two-dimensional Fast Fourier Transforms (2-D FFTs). The technique was developed at the Image Processing Laboratory of the Jet Propulsion Laboratory. Unlike existing techniques, it fully utilizes the information content of the 2-D FFT. Past studies (e.g. Bunting and Fournier, 1980; Toldalagi and Lebow, 1982) dealt with information extraction from 1-D power spectra as derived by radially averaging 2-D FFTs. Our technique utilizes the 2-D FFT to extract pattern size both parallel and perpendicular to the major axis, pattern shape and pattern orientation.
A Low Cost 'Super-Micro' Computer System for Large Format CCD and VLA Data Reduction
Authors: Nousek John A. , Truax Ryland J.
Published: February 2023

Modern astronomical problems require extensive computational power, particularly in the area of interactive data handling, which are not adequately dealt with through the traditional large main frame computer. At Penn State we are contemplating major observational projects involving VLA observations and large format (800 x 800) CCD data of both X-ray and optical nature.
Semiconductor photonic integrated circuits
Authors: Koch T. L. , Koren U.
Published: February 2023

Photonic integrated circuits (PICs) are that subset of optoelectronic integrated circuits (OEICs) that focus primarily on the integration of interconnected guided-wave optical devices. A good example of a simple but potentially important PIC is the butt-coupled integration of a distributed feedback (DFB) laser with an electroabsorption modulator to provide a low-chirp high-speed modulated source.1Many researchers have also pointed out that three-section continuously tunable distributed Bragg reflector (DBR) lasers are also PICs, with an integrated multielement resonator composed of a separately controlled gain medium, phase shifter, and tunable Bragg mirror.2-4
Laser diodes for optical interconnects
Authors: Harder Ch. , Buchmann P. , Meier H. , Moser A. , Vettiger P. , Webb D. , Wolf P.
Published: February 2023

Optical interconnects for data communication between and within computers will eventually replace electrical interconnects only if the optical interconnects are smaller, consume less power, and have larger data transmission capacity. The requirements for laser diodes for optical interconnects are therefore quite demanding. The laser diodes have to be efficient, temperature insensitive, small, and reliable and must display low noise. Special attention has to also be given to the problem of coupling arrays of laser diodes to optical fibers or optical waveguides within a small package. Eventually the electronic driving circuit should be integrated monolithically to decrease the size and power dissipation of the transmitter even further. AlGaAs quantum-well laser diodes with etched mirror facets fabricated in a full wafer technology (FWT) meet most of these requirementsand are therefore the prime choice for optical interconnects.
Improved planar monolithic integration of an InGaAsP/InP buried-heterostructure laser diode with an enhanced barrier MESFET on InP
Authors: Chakrabarti U. K. , Wynn J. D. , Seabury C. W. , Dutta N. K. , Byrne E. K. , Karlicek R. F.
Published: February 2023

A mature optoelectronic integrated circuit (OEIC) technology is expected to offer benefits in the areas of increased functionality, improved reliability, size reduction, higher performance, and, finally, reduced cost. Although significant progress has been made in OEICs, the problem of interconnection between photonic device (e.g., laser diode, LD) and an electronic device (e.g., field-effect transistor, FET) still exists because of nonplanar topography. In this paper we will present a fabrication technology for which the above problem is eliminated.
Synthesis of quantum-wire structures for photonic technology
Authors: Gossard Arthur C.
Published: February 2023

Quantum-wire photonic structures in which active electrons occupy only the lowest quantum state of the wire require that wire widths be smaller than those obtainable by currently available lithographic techniques. An alternative approach to obtain the requisitely small dimensions for quantum-wire widths is to use the periodicity provided by atomic steps on a slightly off-axis crystal surface (i.e., the steps on a crystal surface misoriented by a small angle with respect to a principal crystal axis) as a basis for small lateral structures. Microstructures with such lateral compositional features have recently been produced by alternate fractional monolayer epitaxy on atomically stepped surfaces. The structures, which consist of superlattices, tilted or normal with respect to the crystal surface, are produced by depositing alternately half-monolayer coverages of GaAs and AlAs by either molecular-beam epitaxy or metal organic chemical vapor deposition. When enclosed between barrier layers grown before and after the tilted superlattice, the superlattice becomes an array of quantum wires. The tilt angle of the superlattice and the uniformity of the superlattice period are determined by flux exposures and surface smoothness and are sensitively dependent on growth conditions. In situ electron diffraction, postgrowth examination of cross sections by transmission electron microscopy, and observation of superlattice surfaces by atomic force microscopy after oxidation and etching will be presented. These studies permit us to assess the grown structures and to correlate their properties with observed optical properties.
Theoretical study of grating-assisted ion-exchanged glass waveguides
Authors: Najafi S. Iraj , Lamouche Guy
Published: February 2023

Grating-assisted ion-exchanged glass waveguides are potentially useful in sensor, communication, and signal-processing applications. To design such devices with specific performance characteristics, we must have an accurate knowledge of their optical behavior.
Collective dynamics of semiconductor laser arrays
Authors: Winful Herbert G.
Published: February 2023

In this paper we consider the spontaneous emergence of organized behavior and spatiotemporal chaos in an array of coupled semiconductor lasers. In the absence of coupling, each laser in the array exhibits a constant, steady-state output intensity in response to a constant input pump current. For constant pump currents above lasing threshold, the individual lasers do not exhibit any interesting instabilities such as chaos. In the presence of coupling the constant steady state can lose its stability, and nontrivial spatiotemporal complexity results. The nature of spatio-temporal dynamics depends on the strength of the coupling between adjacent elements. For low coupling strengths the stable steady state is one in which the fields in adjacent elements have nearly equal amplitudes and a phase difference close to π. As the coupling is increased a Hopf bifurcation to a spatially ordered and temporally periodic output is obtained. Further increases in coupling strength lead to full spatiotemporal chaos.
Bistable optical switching using bubbles
Authors: Jackel Janet L , Johnson John J.
Published: February 2023

We have demonstrated bistable optical switching by using the creation and destruction of bubbles produced through the electrolytic dissociation of water into hydrogen or oxygen. So long as the bubbles do not merge, they persist nearly indefinitely, but if the bubbles are permitted to merge in the presence of a catalyst, the oxygen and hydrogen recombine rapidly, destroying the bubble.
Rate-equation model for optical logic devices
Authors: Priest J. A. , Balestra C. L , Clay B. G. , Zediker M. S.
Published: February 2023

The effects of saturable gain and saturable absorption have been of interest for optical logic devices because of potential switching times of the order of a few picosecond. Through saturable gain, a semiconductor laser is used to pump a second laser, stimulation emission that will not be captured into the lasing mode of the latter. This reduces the amount of usable gain in the cavity thereby reducing the output intensity. With saturable absorption, an absorbing region within the laser cavity is optically pumped by a second laser. If the laser is biased below threshold, the pumping by the second laser will increase the electron and hole densities in that region, thus increasing the gain. This permits the laser to begin lasing.
All-optical switching of picosecond pulses in a GaAs/GaAlAs multiple quantum-well waveguide directional coupler
Authors: Li Kam Wa P. , Miller A. , Roberts J. S. , Robson P. N.
Published: February 2023

A multiple quantum-well (MQW) layer was designed to support a single slab mode for both the TE and TM polarizations. Strain-induced waveguides were fabricated by plasma-enhanced vapor-phase deposition and etching of silicon nitride to leave stripes of the film 2000 Å thick and widths ranging from 4 to 10 μm on the surface of the MQW layer. A schematic drawing of the waveguide cross section is shown in Fig. 1. The processed layer was cleaved at the two ends to leave waveguides that were approximately 1 mm long. The narrowest waveguides only allowed for the propagation of the fundamental mode under the center of the stripe, whereas the wider waveguides were found to support two edge modes under the inside edges of the SiN
x
film. The two edge modes were strongly coupled through the overlap of their evanescent tails and the structure exhibited directional coupler properties with a critical coupling distance of approximately 1 mm.
Multiple index passive components
Authors: Nolan Daniel A.
Published: February 2023

A single-mode technology capable of fabrication of a variety of passive fiber components for the subscriber loop is discussed. In the fabrication process, fibers are stripped and embedded in a third index glass matrix (Fig. 1). The composite glass structure subsequently is heated and tapered to induce power transfer to the adjacent fiber or fibers, in the tapered region, the mode power distribution of the initial LP01 mode is expanded into the third index material as a result of the changing geometric configuration. The coupling mechanism can be adequately described using coupled mode theory,1 and the eigen solution to the multiple index medium.2,3
Strip loaded polymeric optical waveguides with low loss
Authors: Neil M. A. A. , Sharpe J. P. , Paige E. G. S. , Cherrill M. J. , Broomfield S. E. , Sheard S. J.
Published: February 2023

Polymer systems show great promise as materials for integrated optics. One important type of system is the guest/host system where the active layer is a polymeric matrix holding an active ingredient in solid solution. Methods previously developed for producing strip guides usually involve complex processing such as dry etching, which can also chemically or physically damage the active component. We have investigated several methods for creating waveguides by loading with a thin strip of high-index material. The advantage of using this technique is that little of the guided optical power travels in the loading layer and hence the final waveguide has a high tolerance of imperfections in that layer, such as optical loss or geometrical variations. Thus low-loss waveguides can result from simple processing techniques. Simultaneously a high proportion of the light (70%–80%) is confined in the active layer, increasing its effectiveness.
Gap soliton in periodic waveguide structures
Authors: Sipe J. E.
Published: February 2023

Over the past four years there have been a number of theoretical studies of gap solitons and related phenomena. Gap solitons are excitations that can appear in nonlinear periodic optical structures, such as a multilayer film or a corrugated waveguide. Such structures have photonic band gaps, ranges of frequencies at which light cannot propagate through the structure in the linear limit. In the presence of nonlinearity, however, the material can be locally "tuned out of the gap" if intensities are high enough, and self-localize excitations can form. First observed in numerical studies, these excitations can, in certain limits, exhibit the robustness of solitons. They can lead to optical bistability, multistability, and chaos in the optical response of nonlinear periodic structures, as well as to the ultraslow propagation of light.
High-gain GaAs optoelectronic thresholding devices for neural network implementation
Authors: Lin Steven , Psaltis Demetri , Kim Jae
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. Monolithic optoelectronic integrated devices are candidates for these neurons. However, in order for these devices to be used as neurons in a practical experiment, they must be large in number (104/cm2 - 106/cm2) 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.
Bichromatic all-optical signal-processing devices in filter glass
Authors: Wood V. E. , Busch J. R. , Krak S. J. , Ridgway R. W.
Published: February 2023

All-optical bichromatic signal processing devices have the advantage over monochromatic configurations that the signal-controlling mechanisms are independent of the signal itself. Moreover, the control beams can be in troduced and controlled independently, a particular advantage in guided-wave-optic configurations. Bulk and guided-wave experiments addressed the effects of using a pulsed nitrogen-pumped dye laser at 490-530 nm as the control beam and a CW helium-neon laser at 632.8 nm as the signal in Corning 3-70 and 3-71 filter glasses.
InGaAs/InP strained quantum-well lasers
Authors: Temkin H.
Published: February 2023

Biaxial strain applied to quantum wells of InGaAs grown on InP induces significant changes in their optical and electronic properties. We describe Fabry-Perot and distributed feedback quantum-well lasers grown with compressive or tensile strain and discuss the underlying device physics. We show that strain can be used to produce lasers with improved static and dynamic characteristics.
A new structure broad-band traveling wave Ti:LiNbO3 optical phase modulator
Authors: Miyamoto H. , Ohta H. , Tabuse K. , Iwaoka H. , Miyagawa Y.
Published: February 2023

Broadband optical modulators are required for optical communication and optical measurement. The modulation bandwidth is limited by velocity mismatching between a microwave signal and an optical signal. Also for practical use, 50Ω characteristic impedance matching and low driving voltage are required to modulators. To solve these problems, we adopted a new structure with the buffer layers partly removed. (Fig. 1)
Photonics research at DARPA
Authors: Yang Andrew C.
Published: February 2023

DARPA photonics program for information processing and transmission will be described. The program consists of segments for research and development of optoelectronic components and device processing technology as well as demonstration and insertion of functional photonic subsystems.
Mode-evolution-type optical beam combiner for coherent receivers
Authors: Smith D. A. , Baran J. E. , Jackel J. L. , Wagner R. E. , Welter R.
Published: February 2023

We have used an asymmetric x-junction (ASX) as a polarization-independent sum and difference beam combiner. This component is integrable with adiabatic polarization splitters to build a fully passive integrated front end for a polarization-diversity coherent optical receiver.1 The advantage of the adiabatic junction device over directional coupler (DC) beam combiners is tire absence of a strict interaction length required for balanced separation.
Tilt Servo using a Liquid Crystal Device
Authors: Murao N. , Iwasaki M. , Ohtaki S.
Published: February 2023

Adaptive optics systems have been studied extensively in recent years. In this field a phase shift modulator is used and it was found to be useful for the image enhancement, beam shaping, image processing, etc.1) 2)
Differential MO Readout Enhancement with Retardation Plate of an Arbitrary Phase Shift
Authors: Prikryl Ivan
Published: February 2023

It is well-known in magneto-optical (MO) recording that undesired readout beam ellipticity can be removed by using a quarter-wave plate or an adjustable compensator1. We will show that this ellipticity can be removed by any retardation plate, if its retardation magnitude is larger than the readout beam phase shift, or more precisely, if its retardation obeys the condition where δ is the phase shift between two orthogonal polarization components of the return beam along the carrier and MO signal polarization directions, and Δ is the retardation of the retardation plate. If the phase shift δ does not equal kπ, where k is an integer, then the return beam will be elliptically polarized. The carrier polarization direction is the polarization direction of a linearly polarized beam incident on a MO disk.
635nm Laser Diode with Pulsation Mode for DVD Optical Pickup
Authors: Yoo Tae-Kyung , Choi Won-Jin , Kim Jong-Seok , Cho In-Sung
Published: February 2023

635nm wavelength laser diodes have been one of the most important components establishing the characteristics of DVD optical pickups. Especially, the spectral mode of laser diodes plays a great role in determining the signal-to-noise(S/N) performance of optical pickups, because the laser beam reflected from the disc is partly re-injected into the laser diode and interferes with the laser source[1]. In order to suppress this interference, the laser diodes need a self-pulsation property in inherent spectral characteristics, which is able to reduce the interference considerably. However, it is very difficult to obtain the stable self-pulsation modes in 635nm AlGaInP laser diodes. As a result, high frequency modulations of laser diodes were widely used to generate artificial pulsation modes in developing DVD optical pickups. Unfortunately, this approach causes parasitic effects and makes the DVD optical pickup complicated.
Dual Layer Disk Overview
Authors: Kashiwagi Toshiyuki
Published: February 2023

The Dual layer disc (DLD) is the simplest realization of a multi-layer disc that opens up the possibility of three-dimensional recording in the optical disc world. DLD technologies first appeared in patents from several companies in the last decade or so. (For example, refer to [1] from Philips). DLD technologies are very important in optical disc systems because there are no other possibilities by which we can acquire a factor of 2 increase in recording capacity while using a conventional optical pickup. Although this advantage has been known for many years, the DLD was thought to be too difficult to make for commercialization. However, the DLD has been finally adopted as the Digital Video Disc (DVD). Since then, a great deal of effort has been expended to make the DLD truly feasible for mass production. DLD technologies have been updated and they are now about to be transferred from the laboratory to factory. In this paper, I will describe the principles of these DLD technologies.
The course of developing Digital Video Disc
Authors: Tanaka S.
Published: February 2023

A Digital Video Disc (DVD) is expected to play a significant role in the coming multimedia era. In the beginning of developing a high density optical disc applicable to a DVD, basic factors of an optical disc are reconsidered free from accepted idea to prove the ideal figure. First of all disc thickness was reconsidered and optimized to choose 0.6 mm1). That is because a higher NA objective lens can be used without increasing of aberration caused by disc tilt. A high efficiency data format suitable for 0.6 mm discs has been also developed. As the result a DVD having 5 GB of user capacity in CD size has been achieved. This DVD can contains more than 140 minutes of video signal with the same quality as the conventional analogue video discs.
A Migration Path on Rewritable Optical Disk Compatible with DVD
Authors: Yamagami Tamotsu
Published: February 2023

Summary not available.
Video Disk Recorder System Using Magneto-Optical Disk
Authors: Murata Seiji , Asano Kenji , Mamiya Noboru , Suzuki Yoshihisa , Takahashi Seiichirou , Kunisa Akiomi , Itou Nobuo , Torazawa Kenji
Published: February 2023

Recently details of some video disk recorder systems have been reported(1)(2). It is necessary for such a system for consumer use to have a recording time of more than 2 hours using a small optical disk the same size as a CD. A larger and larger capacity is required.
High density recording technology on phase change disk system
Authors: Ohara S. , Akahira N. , Ishida T.
Published: February 2023

The rewritable optical disk is expected as the key device for storage at the dawn of the full-scale multimedia age. It requires a large storing capacity so as to record and reproduce great amounts of data including motion pictures and audio information as well as data for computer processing itself. This paper reports land and groove recording(1) (4) (5) and mark edge recording technologies(2)(3)on phase change media, the key role in realizing high capacity.
High-Density Phase-Change Recording
Authors: Jacobs B.A.J. , Duchateau J.P.W.B.
Published: February 2023

In recent years the phase-change optical recording technology has advanced remarkably and has become a very attractive alternative to the magneto-optic technology for erasable optical recording systems. In particular, the discovery of rapidly crystallizing material systems such as Ge-Sb-Te and Ag-In-Sb-Te accelerated the realization of a rewritable phase-change optical disc. Last year, the 'PD' system was introduced and in the second half of 1996 Philips et al. will launch the 'CD-Erasable' system, a phase-change technology for data applications, having a high degree of compatibility with the read-only CD-system.
Potentiality of the Ag-In-Sb-Te Phase Change Recording Material for High Density Erasable Optical Discs
Authors: Shinozuka Michiaki , Shibaguchi Takashi , Abe Michiharu , Ide Yukio
Published: February 2023

We have been developing the Phase Change (PC) optical discs comprising Ag-In-Sb-Te alloy as the recording material. This material has so many advantages such as in erasability and controllability of mark length recording that it is now available as CD-Erasable discs [1] on a commercial basis.
High density optical recording on Dye material Disc-Approach for 4.7GB
Authors: Hamada Emiko , Fujii Toru , Tomizawa Yuji , Iimura Shinichiro
Published: February 2023

Today, DVD is expected as a tomorrow's carrier for mass data of computer as well as for a high quality motion video.
Crosstalk-Suppressed Readout System Using A Shading Band
Authors: Dobashi Hisanobu , Tanabe Takaya , Yamamoto Manabu
Published: February 2023

As multimedia becomes more common in computer usage, stored information is changing from still images to moving pictures. As a result, higher density storage is required in optical disk systems. One method of increasing recording density is to narrow the track pitch; however, this increases crosstalk from adjacent tracks during playback. Several methods of overcoming this problem have been studied, such as land/groove recording1) and crosstalk canceling using a three-beam optical head2). However, these methods require either additional disk fabrication or complicated optical heads.
Liquid Crystal Shutter - Optical Head for DVD Player with CD Compatibility
Authors: Lee Man-Hyung , Kim Hyun-Jun , Kim Jung-Bae , Chung Won-Eull , Park Song-Chan , Choi In-Ho , Jeong Seong-Yun , Song In-Sang , Ko Eui-Seok , Kim Dae-Young , Kim Jin-Yong
Published: February 2023

The newly agreed high-density read-only format, DVD, adopts two 0.6 mm disks attached back to back as a standard, in order to allow the optical system to have more tilt angle margin, with high numerical aperture (NA) objective lens. On the other hand, the conventional CD family disks are 1.2 mm thick, single side. Since diffraction-limited spot quality is essential to read the preformed pit signals with sufficient accuracy, spherical aberration caused by the disk plate must be corrected appropriately. We have proposed the new optical head with aperture-control capability using liquid crystal shutter (LCS), which can play both CDs and DVDs with single objective lens which is corrected for only DVD disk thickness.
Distributed Digital Servo
Authors: Monen Marinus J.
Published: February 2023

Optical disks manufactured by a continuous web process [1] are attractive from a cost point of view, in comparison with conventional injection molded disks, but require a more complex servo system implementation to deal with the more challenging characteristics of track distortions. A new servo system, Digital Distributed Servo (DDS), is proposed that deals effectively with these characteristics and of which the implementation has become attractive due to the strong progress over the last years in price/performance of DSP based integrated electronic systems. In addition DDS requires little disk overhead, has a long term potential for low cost drive implementation and has a natural growth path for disk capacity and drive performance.
Compact Disc - Direct Access Storage Disc (CD-DASD)
Authors: Howe Dennis G.
Published: February 2023

A Compact Disc - direct access storage (CD-DASD) disc has information recorded on its surface in a manner that enables randomly located, isolated (the recorded spiral track does not have to be contiguously written), fixed-length (4-Kbyte) blocks of data the disc to be reliably read via a Compact Disc player that has only minimal modifications made to it. Appropriately modified Compact Disc readers will be able to perform DASD-like data retrieval when such a disc is used. In addition, a Compact Disc writer/reader (such as a CD-E/R drive) that is configured to use the disc described in this paper will be able to write/read data in randomly located sectors that can be individually written and/or accessed as is done in a DASD device; lead-in/lead-out sectors and incremental writing (i.e., appending new information directly to the previously written portion of the spiral disc groove) as is practiced in current CD-R devices is not required.
A Magneto-Optic Testbed for 532nm Sensitive Media
Authors: Milster T. D. , Bletscher W. L. , Walker E. P. , Hamilton S. B. , Caldwell M. L.
Published: February 2023

The storage capacity of optical media can be increased by using shorter-wavelength sources. This paper describes a magneto-optic testbed that uses a 532 nm frequency-doubled Nd: YAG light source for magneto-optical media with 0.75 μm track pitch. Up to 25 mW of green light is available at the recording layer.
Optical Disk Encoding Rate for Minimum CNR
Authors: Gerpheide John M.
Published: February 2023

Improvements in optical disk media and drives have led to increased data transfer rates. One important aspect of the media format standard is the data encoding rate, which is specified by the recording channel modulation code and the forward error correction parameters. In this paper the relationship between data transfer rate and the encoding rate is investigated. We show that for a given data transfer rate the media CNR requirements can be minimized by proper selection of the data encoding rate. An important conclusion of this analysis is that M-ary channel codes minimize the CNR requirements for high data rate optical recording systems. Consequently, M-ary encoding is a very effective way of attaining data transfer rates above those achievable by conventional binary recording technologies.
Numerical Analysis of Tracking Error on High Density Optical Disks by Vector Diffraction Model
Authors: Liu Pei-Yih , Shieh Han-Ping D.
Published: February 2023

High density optical disks are progressing rapidly recently. Shrinking the track pitch and the size of recorded pits are among the key technologies to attain higher density storage. However, the decrease in track pitch requires that the tracking servo control system be more precisely than conventional system. Scalar diffraction theory is usually used to calculate the optical readout of conventional optical disk storage system. However, scalar diffraction theory is valid only as long as the wavelength of the incident light is small compared with characteristic transverse dimensions of the scattering structure. As the transverse dimension of track pitch is no longer larger than the wavelength for higher density optical disks, vector diffraction theory1,2 becomes necessary to analyze the optical readout.
Reversible Phase Change and Rewritable Performances of Phthalocyanine Compounds
Authors: Gan Fuxi
Published: February 2023

Organic materials have received considerable attention recently, due to their easy preparation and different variety. The most applicable field in optical storage is used as write-once media, such as recordable compact disk (CD-R). It is of great interest to explore new organic compounds, which can perform rewritable storage. It is well known that the photochromic organic compounds are always heat and light unstable. The phthalocyanine compounds have received considerable attention because of their good thermal and chemical stability which ensure a long storage life. We have reported the write-once performances and reversible optical property change of phthalocyanine thim films(1,2). In this paper the reversible phase chane and rewritable performances are presented.
Optical Disk Spatial Light Modulator
Authors: Taylor T.S. , Wilson M.M. , Hartman R.L. , Farr K.B.
Published: February 2023

Advances in technology have made optical disk technology for optical signal processing realizable. The limiting factor in optical image processing is the spatial light modulator (liquid crystal or similar devices). Higher resolution and faster filter access makes optical disk technology an attractive alternative. Images are represented onto a CD by a single stream of 1's and 0's read by the optical pickup system. Digital processing is then performed on the image. We propose to write 2-dimensional images directly to a CD as shown in Figure 1. The 2-D images can then be accessed by our optical processor so that we can perform optical image processing.
Parallel Access Optical Disks as Memory and Processing Elements for High Speed Pattern Recognition Systems
Authors: Davison C. , Coupland J.M. , Halliwell N.A.
Published: February 2023

The potential of optical processing techniques for high speed pattern recognition and vision systems was demonstrated over thirty years ago by Vanderlugt [1]. In his early experiments Vanderlugt prepared linear filters with transfer characteristics matched to an object of interest using holographic techniques. Once inserted into a coherent optical processing system these elements could be used to interrogate an input transparency, clearly marking each occurrence of a given object. Since this type of filter is matched to a single signal, however, it is sensitive to small changes in structure, scale and rotation which occur, in general, if the system is required to identify a particular class of object. In order to alleviate this problem, computer synthesis has facilitated the fabrication of other linear filters capable of classifying objects according to rules obtained from sets of training images [2].
A Novel Erasable and Rewritable Optical Memory Utilizing Photostimulated Luminescence in Eu and Sm Co-doped SrS Phosphor Ceramics
Authors: Nanto H. , Douguchi Y. , Nishishita J. , Kadota M. , Kashiwagi N. , Shinkawa T. , Nasu S.
Published: February 2023

New systems to optical memory, which are based on the photostimulated luminescence (PSL) phenomenon in electron trapping phosphor materials for optical storage, have been studied in the fields of optical parallel Boolean logic operation [1], two-dimensional optical associative memory [2] and optical neural networks [3,4], The electron trapping phosphor materials can emit different output photons that correlate spatially in intensity with input photons. Consequently, the phosphor materials can be used to store optical information as trapped electrons and the information stored can be read out by a laser beam scanning of the phosphor material. The unique features of the electron trapping phosphor materials that exhibit the PSL phenomenon provide the potential for high bit storage densities, high data transfer, and fast recovery speeds. [5] Important characteristics of a good electron trapping phosphor materials for optical memory are high PSL brightness for low noise, short luminescent lifetime for minimum readout time, and low light scattering for high bit densities. Especially, the electron trapping phosphor materials using transparent thin film provides an efficient PSL and low light scattering.
Recording And Read-Out Of A Cholesteric Liquid Crystal Based Multilayer Disk
Authors: Schlichting Wolfgang , Faris Sadeg , Fan Bunsen , Haag John , Lu Zhijian , Li Le , Milster Tom , Luo Hui
Published: February 2023

Numerous applications demand terabyte data storage capacities and data rates exceeding 1 gigabyte/sec (GB/s). The logical means of avoiding the wavelength bottleneck associated with conventional optical disks is by layering. In current state-of-the-art layered disk technology, semi-reflective-layers and depth of focus is used for addressing. The inherent problem with this approach is a loss of light, as high as 70% per semi-reflective layer.
Computation of Normal Velocity from Local Phase Information
Authors: Fleet David J. , Jepson Allan D.
Published: February 2023

Recently it was shown that linear spatiotemporal filters can be tuned to relatively narrow ranges of normal velocity [1, 7, 16]. Despite this tuning, a subsequent stage is still necessary to compute velocity estimates because 1) the filters are linear and therefore do not yield quantitative estimates of speed and orientation, 2) more accuracy is required than that given by the filter tunings alone, and 3) if a unique 2-d flow field is desired, then the aperture problem must be overcome as the filters are tuned only to normal velocities. Adelson and Bergen [2] suggested the computation of velocity from the ratios of energy in the outputs of differently tuned filters. Heeger [9] based the computation of 2-d flow on a least-squares fit of local energy to a model of 2-d translation.
Tracking Objects with Eye Movements
Authors: Coombs David J.
Published: February 2023

The main problem of tracking moving objects lies in discriminating the target from the background. Vergence eye movements can be used to distinguish the target.
The Use of an Anthropomorphic Visual Sensor for Motion Estimation and Object Tracking
Authors: Sandini G. , Bosero F. , Bottino F. , Ceccherini A.
Published: February 2023

The use of an anthropomorphic visual sensor in computer vision has already been object of many studies, showing the intrinsical efficiency that a retina_like structure has if operating in man_oriented environments [1] [2]. On the ground of this belief a project has started to realize a visual system that, exploiting such kind of sensor, should be able to carry out simple functions typical of the human visual system.
Detection and Characterization of Breast Tumors by a Laser Pulse Mammograph
Authors: Rinneberg Herbert , Grosenick Dirk , Wabnitz Heidrun , Moesta K. Thomas , Schlag Peter M.
Published: February 2023

The paper presents case studies of tumor detection and characterization by time-domain optical mammography. Optical mammograms representing photon counts in different time windows of measured distributions of times of flight allowed to detect tumors and one cyst. Tumor contrast was higher at λ = 670 nm compared to 785 nm. Besides effective optical properties derived from a homogeneous diffusion model, the optical properties of tumors were obtained calculating the diffraction of photon density waves by a spherical object. Absorption coefficients of one particular tumor showed it to be hypoxic and to contain more blood compared to the surrounding tissue.
Quantification of Breast Tissue Constituents from Time-Resolved Reflectance Spectra
Authors: Cubeddu Rinaldo , D’Andrea Cosimo , Pifferi Antonio , Taroni Paola , Torricelli Alessandro , Valentini Gianluca
Published: February 2023

The optical properties of the breast of a 35 yr. old volunteer were studied as a function of the menstrual period using a system for time resolved reflectance spectroscopy from 610 to 1000 nm. The availability of a wide spectral range allowed us to derive the mean concentration of the main tissue absorbers (water, lipids, oxy-, and deoxy-hemoglobin), and to infer information on the microscopic structure. Reflectance spectra were richer of blood and lipids, while transmittance spectra showed a more marked water peak. Changes of absorption properties were observed as a function of phases within the menstrual cycle with an increase in blood and lipid absorption in reflectance and of water content in transmittance while approaching menstruation. Scattering spectra experienced a drop in slope across ovulation, suggesting a change in size and structure of scatterers. This spectroscopy technique can be of great help to understand breast physiology from an optical point of view, and to help further improvement of optical mammography.
Bulk Optical Properties of Normal Breasts and Tissue Phantoms Obtained with Clinical Optical Imager
Authors: Durduran Turgut , Culver J. P. , Zubkov L. , Choe R. , Holboke M. , Pattanayak D. N. , Chance B. , Yodh A. G.
Published: February 2023

A clinical diffuse optical imager in the compressed breast geometry is used to determine the bulk optical properties and blood saturation in breast tissue of volunteers. We use a finite difference based forward model for the estimation of bulk tissue optical properties. The method is tested on tissue phantoms made of balloons and Intralipid, and is then applied in-vivo. Careful modeling of the chest wall was found to be critical for optical property determination.