bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and operation of a hybrid LED/LD-pumped phosphor-converted white-light lamp
Authors: Chakraborty M. , Hasan M. M. , Kenreich J. R. , Jadwisienczak W. M. , Rahman F.
Published: February 2023

Illumination sources based on phosphors, pumped by laser diodes (LDs), have seen rapid
developments over the past decade. Here, we present a new, to the best
of our knowledge, design that features both spectral richness and the
capability for high brightness. Complete design details and
operational characterization have been described. This basic design
can be extended in various ways to customize such lamps for different
operational requirements. A hybrid arrangement of both LEDs and an LD
is used to excite a mixture of two phosphors. The LEDs, in addition,
provide a blue fill-in to enrich output radiation and to tune the
chromaticity point inside the white region. The LD power, on the other
hand, can be scaled up to generate very high brightness levels that
are not achievable with pumping from LEDs alone. This capability is
gained using a special transparent ceramic disk that carries the
remote phosphor film. We also show that the radiation from our lamp is
free from speckle-producing coherence.
Design of Passive Waveguide Components
Authors: Fabricius N. , Wolf B. , Foss W.
Published: February 2023

Integrated optical components made by ion exchange in glass are now used in German telecommunication networks and industrial sensor applications. Therefore the production yield and the reliability under hard environmental conditions have to be optimized during the design procedure. Examples are given in the talk.
Design of multilayer cladding waveguides and their applications
Authors: Kokubun Yasuo
Published: February 2023

Multilayer thin films can produce various states of complex reflection coefficient by regulating the thickness and refractive index of each layer and the angle of incidence.
Current Issues in Free-Space Digital Optical Systems
Authors: Hinton H. S.
Published: February 2023

Over the past 9 years there has been an increasing interest in digital optical systems, both computing and switching. It began in 1984 with a demonstration by USC of an optical master-slave flip-flop based on Hughes liquid crystal light valves as optical logic gates and holographic interconnects between the gates.[1]
Simulation of Highly Multimode Star Couplers in Polymers
Authors: Ilić Igor , Scarmozzino Robert , Osgood Richard M. , Yardley James T. , Beeson Karl W. , McFarland Michael J.
Published: February 2023

Optical star couplers are widely used in lightwave local-area networks for even distribution of signals among several users.
Phase Grating Optimization Using Genetic Algorithms
Authors: Johnson Eric G. , Abushagar Mustafa A.G. , Kathman Alan
Published: February 2023

With the advancement of computer technology, it has become necessary to interconnect processors using optical connections rather than wires.
Applications of Diffractive Optics with Only A Zero Order
Authors: Noll Robert J.
Published: February 2023

Gratings whose spacing is short compared to the wavelength of incident radiation have no diffracted orders as can be seen from the grating equation for normal incidence
HOE For Wavelength Stabilization and Selection for WDM in Lightwave Communications
Authors: Zhou Haixian , Ih Charles S. , Tian Rongsheng , Xia Xiaoqing
Published: February 2023

The use of WDM (Wavelength-Division-Multiplexing) is an attractive alternative to increase the information capacity of an optical communication system.
Fresnel Ping-Pong Algorithm for Two-Plane CGH Display
Authors: Dorsch Rainer G. , Lohmann Adolf W. , Sinzinger Stefan
Published: February 2023

A breakthrough in 3D display was expected when computer generated hologams were invented about 25 years ago.
Fidelity of PostScript™-Generated Masks for Diffractive Optics Fabrication
Authors: O'Shea Donald C. , Suleski Thomas J.
Published: February 2023

There is a technique for generating binary masks for the fabrication of diffractive optical elements that uses commercially available desktop publishing hardware and software in conjunction with a standard photoreduction camera1.
Color Correction in Athermalized Hybrid Lenses
Authors: Behrmann Gregory P.
Published: February 2023

Recently, it has been shown that it is possible to design athermalized hybrid lenses by combining the thermal properties of refractive and diffractive lenses.
Design Issues in Monolithic Waveguide Integration
Authors: Deri R. J.
Published: February 2023

Advanced fiber optic systems for communications and sensing are using increasingly sophisticated combinations of optical and optoelectronic devices, with optical functions such as power splitting/switching and wavelength separation.
The Use of Fourier Methods To Analyze the Effects of Birefringence in Optical Disk Substrates
Authors: Bernacki Bruce E. , Mansuripur M.
Published: February 2023

Current methods of producing optical disk substrates involve injection molding of polycarbonate plastics.
Alignability Versus Signal Density in Integrated Planar-Optical Interconnect Packages
Authors: Ghosh Anjan K. , Beech Russell S.
Published: February 2023

Free space optical interconnects are well suited to complex, 3-D interconnect patterns and high density parallel interconnections because of their low cross-talk and the ability of beams to pass through one another with minimal interference [1].
Multiple-Plane Optical Interconnections Using Through-Wafer Hollow Dielectric Waveguide Vias
Authors: Norte A. D. , Willner A. E. , Shieh W. , Tanguay A. R.
Published: February 2023

It is of critical importance for future data communications to connect multiple high-speed processors simultaneously in a local environment.
A Technique for Reducing the Spectral Width of an LED
Authors: O'Toole Michael M.
Published: February 2023

The spectral width of an LED is an intrinsic property of the LED that depends on the type of material, the peak emission wavelength, dopant, and carrier density
Birefringent Polarization Ray Tracing
Authors: McClain Stephen C. , Chipman Russell A.
Published: February 2023

The fundamental tool used for design and analysis of optical systems is geometric ray tracing. In isotropic, homogeneous, non-optically active media the procedure is simple -- rays travel in straight lines except at interfaces, where reflection and refraction occur.
Effective Medium Theory Approach to Guided-Mode Resonances
Authors: Norton Scott M. , Raguin Daniel H. , Morris G. Michael
Published: February 2023

Guided-mode resonances are a form of Wood's anomaly, which were first properly characterized as a resonance effect by Hessel and Oliner.
Optical Device Packaging Technology for Fiber-Optic Communications
Authors: Abe Yuji
Published: February 2023

Optical device packaging technology is one of the key technologies for fiber-optc communication systems.
Large Memory Applications for Optical Disk
Authors: Goldberg Mark W.
Published: February 2023

Optical disk memory hardware offers a unique combination of performance features that renders it an attractive solution to a variety of large memory problems. Table 1 provides a comparison of optical disk with other digital storage technologies. The table is intended to indicate trends rather than to provide information about specific hardware. The most dramatic comparison is between optical disk and computer tape. Optical disk offers a lower cost- per-bit, much improved accessing characteristics, higher volumetric efficiency, and improved archival characteristics. The non-erasable nature of optical disk makes it most attractive for those large memory applications where the information constitutes a relatively stable archive. In such applications, where computer tape is presently used extensively, the lifetime of a tape is strongly dependent on how the tape is used, handled, and stored. Regular tape cleaning and rewinding, careful handling, and a controlled storage environment are a must if greater than two year tape life is to be achieved. Optical disk is not sensitive to the level of use, will not require regular maintenance, and will be tolerant of a somewhat wider range of storage environments.
Magneto-optical disc with a reflecting layer
Authors: Ohta K. , Takahashi A. , Deguchi T. , Huga T. , Kobayashi S. , Yamaoka H.
Published: February 2023

As a reversible large capacity memory, magneto-optical disc has been developed in both fields of medium and system. There have been many studies of rare earth-transition metal alloy thin films since thermomagnetic writing was reported on GdCo amorphous thin film.(1) (2) The Kerr rotations from 0.1° to 0.3° of these films are very small, therefore, it is difficult to obtain high signal to noise ratio(SNR).
Thickness Dependence of Magneto-Optic Effects in Tb-Fe Film
Authors: Chen Tu , Mansuripur M. , Malmhäll R.
Published: February 2023

In the investigation of amorphous rare earth-transition metal (RE-TM) thin films for magneto-optic (M-O) storage applications, optimization of Kerr effect enhancement using dielectric overcoating in a bilayer structure has been the subject of numerous theoretical calculations [1]. It has been generally assumed that the optical constants such as the refractive index, absorption coefficient and dielectric tensor of the M-O film are independent of the film thickness. However, in light of a recent report which shows a strong thickness dependence of magnetic hysteretic properties and Curie temperature of the Tb-Fe films due to variation in the microstructure [2], it is necessary to investigate experimentally the optical enhancement of the Kerr effect in media having varying RE-TM film thickness and compare that to the theoretical results.
An Optical Sealed Disk Assembly
Authors: Kurtz Clark N.
Published: February 2023

The substrate around which the Sealed Disk Assembly (SDA) is developed is a web similar in some respects to those upon which photographic emulsions are coated. As with other substrates for optical disks, before the sensitive recording layers are applied, a surfacing treatment is given to provide extraordinary smoothness. Coatings placed upon properly prepared webs having suitable initial characteristics are equal in quality to those put on glass disks or on aluminum disk substrates, and have defect levels low enough to support optical digital data storage and retrieval applications.
Optical Recording on a Sealed Disk Assembly
Authors: Kay David B.
Published: February 2023

The Sealed Disk Assembly (SDA) requires different interfacing to a read/write machine than does an optical disk, which uses a conventional aluminum substrate. This paper describes a laboratory disk recorder which is designed specifically to interface with the web-based SDA and gives technical performance data to demonstrate how well the disk/recorder interface works.
Two-Regime Hole Opening Process in Tellurium-Alloy Films
Authors: Chen M. , Marrello V. , Gerber U.G.
Published: February 2023

Single layer (≃ 300A thick) Te and Te-alloy films on polymethylmethacrylate substrates are widely studied for possible use as optical recording media. The ablative hole formation process in such media is however still poorly understood. In this paper, data is presented to show that ablative writing in Te-alloy films has two hole opening regimes. This two regime hole opening process is shown to lead to a qualitative understanding of the contrast ratio versus writing laser power characteristics of Te-alloy films.
Hard carbon protective coatings for Te based optical recording media*.
Authors: Moravec T.J. , Chen Di , Shrawagi S.
Published: February 2023

Hard carbon coatings are being studied to see if they can be used as environmentally protective coatings for tellurium based optical recording media. These carbon coatings are mostly amorphous in structure1 and have been referred to as diamond-like in recognition of their typical physical characteristics: high mechanical hardness (2000 Knoop), optical transparency with refractive index greater than 2.0 in the visible and infrared, and high electrical insulation (>1010 ohm cm)1,2. The most common technique for producing these films is by plasma decomposition of a hydrocarbon gas (or plasma CVD, PCVD) and subsequent deposition of a carbon film on one of the plasma system electrode1,3. We have used both this technique and direct carbon ion beam depositor: (C1BD) in experiments to coat Te3.
Optical Writing Process in Textured Media
Authors: Suh S. Y.
Published: February 2023

Textured Ge thin films(1) prepared by reactive ion etching showed a significantly improved writing sensitivity compared to conventional pit-forming writing on the same material. A preliminary theoretical analysis shows that the surface energy stored on the textured columns is sufficient to initiate the writing process. Thus, the energy barrier for the pit formation, other than the energy required to melt a spot itself, is virtually eliminated. This allows the writing sensitivity enhancement.
Spot-Forming Efficiency of Optical Recording Systems Using High-Power Diode Lasers
Authors: Carlin D. B.
Published: February 2023

Diffraction patterns were calculated in order to understand the requirements for achieving efficient imaging of high-power diode laser far-fields in optical recording systems(1) as a function of truncation. A distribution of 22 CDH-LOC diode lasers(2) was studied to determine the variations likely to be encountered in real devices. At 40 mW 50% duty-cycle operation, the full-width at half-maximum (FWHM) was found to range from 6.2° to 10.2° with an average value of 8.1° ± 1.3° (one standard deviation) in the direction parallel to the plane of the junction. In the perpendicular directions, the FWHM's ranged from 18.4° to 35.6° with an average and standard deviation of 27.1° ± 3.4°. We are interested in whether recording optics must be specified for each particular laser or may a single set of appropriately chosen fixed optics yield adequate efficiency for spot formation.
Self—coupled optical pickup
Authors: Mitsuhashi Y. , Shimada J.
Published: February 2023

In a semiconductor laser diode (LD) with an external optical feedback, the occurence of self—coupled effects is well known. One can use the effects for optical memory readout utilizing either the laser power output changes or the voltage changes resulting from the addition of optical feedback (1). The first effect requires for its measurement a photodetector, which may conveniently be placed at the rear of the LD (2). The second effect requires no additional detector for its measurement. This implies that an LD can simultaneously function as a light source and detector. The devices using these effects are named SCOOP. We show the fundamental characteristics of various type SCOOP in our previous work and report a scheme to improve the operational instabilities in the optical memory pickup.
Multichannel Diode Laser Array Optical Recording
Authors: Carlin D.B. , Bednarz J.P. , Kaiser C.J. , Connolly J.C. , Harvey M.G.
Published: February 2023

We are reporting the use of a monolithic array of individually addressable diode lasers as the source for multichannel optical recording. Simultaneous recording of closely spaced tracks has been shown to be effective in achieving extremely high data rates. Such systems have, heretofore, used individually modulated beams formed by splitting the output of an argon ion laser.1 Diode lasers are the preferred source for optical recording applications2 and the use of a monolithic array of high-power, single-mode diode lasers, which can be modulated directly and independently, represents a significant advance towards the realization of compact, efficient high-performance recording systems.
Polycarbonate Substrate for Large Capacity Optical Memory Disk
Authors: Tokuhara Shinji , Onisawa Yoshio , Iyoshi Shuzo , Toba Hirotaka
Published: February 2023

Polymethylmethacrylate (PMMA) was usually used for the substrate for recently developed 20 cm ϕ or 30 cm ϕ optical memory disks because of the excellent optical properties, especially low level of birefringence. But warping by heat and water absorption during usage and storage is the drawback for PMMA substrate from the viewpoint of durability of disks. Polycarbonate (PC) on the other hand is not liable to warp but has generally poorer moldability and higher birefringence. This is the reason why PC could not be used for the disk substrate larger than compact disk size (12 cmϕ).
Thomson-CSF Optical Media Format
Authors: Bricot C. , Cornet J. , Gerard J.L.
Published: February 2023

The Digital Optical Disk Department of Thomson-CSF has developed the GIGADISK 1001 optical disk product as a cost effective write once optical disk storage system.
A High Performance Al: Polymer: Al Trilayer Optical Disk
Authors: Gittleman J. I. , Arie Y.
Published: February 2023

The object of this work was to construct a write-once optical disk of trilayer design which exhibited high performance at low recording power, a property of particular importance for systems based on the GaAs Laser. In addition we sought an absorber material capable of replacing Te. Finally we wished to exploit rf sputtering techniques which, in our own experience, consistently yielded higher signal-to-noise ratios (SNR) than other deposition methods.
Direct Observation of Thermo-Magnetic Writing
Authors: Shieh Han-Ping D. , Kryder Mark H.
Published: February 2023

The nucleation and growth of domains written into a rare earth-transition metal thin film by thermo-magnetic writing with an AlGaAs diode laser have been observed with a high speed magneto-optic camera having a 10 nsec exposure time.lt is observed that the domain is nucleated thermo-magnetically within 20 nsec after the leading edge of the write pulse. The domain grows in size until 50-150 nsec after the termination of the write pulse, then shrinks as the heated area cools and finally reaches an equilibrium size. For very short write pulses, no shrinking of the domain is observed after the termination of the write pulses. It is found that increased laser power or longer laser pulse duration increases the final domain size, but not in proportion to total energy applied. Over 106 write/erase cycles on the same spot on the film have been found to produce no deterioration in magneto-optical performance and no change in nucleated domain size or its erasability.
Optical Disk File Memory for Computer Use
Authors: Tsunoda Yoshito , Abe Shin-ichi , Miyazaki Michio
Published: February 2023

Optical disk file memory using a laser diode is one of the most promising devices for large capacity computer data storage. Several companies have been developing optical disk file memories during the past few years. However, almost all of these memories were designed for document data storage which does not require low error rate and interactive operation with computer. Recently, we have developed a highly reliable optical disk file memory for computer application. The basic specifications, features, and system structure of the developed optical disk file memory and several approaches for reliability improvement are described.
The Optimem 1000 Optical Disk Drive
Authors: Knight Gordon R.
Published: February 2023

The Optimem Division of Shugart Corporation has developed the Optimem 1000 optical disk drive to address the low end market for cost effective write-once optical storage systems. The Optimem 1000 is a 1 GByte per surface drive which is meant to compliment magnetic disk storage. Typical office type applications for this drive are electronic file cabinet storage, and CAD/CAM and medical image storage. In the document storage applications, the optical drive can be used as the central file server along with magnetic disk drives for work in progress.
Design Considerations of an Optical Digital Data Storage Drive
Authors: de Haan M. , Chen Di
Published: February 2023

Digital data storage devices using a laser beam for addressing have been under intense development in recent years. Practical devices are finally reaching the stage for product introduction. In this paper, we will present the considerations given in the design of a 1 Gigabyte capacity write-once-read-only digital data storage drive.
A Unified Measure of Optical Disk Performance: Phase Margin Analysis
Authors: Geyer Frederick F.
Published: February 2023

The characterization of optical disk performance has evolved from video measurements of flat-field signal-to-noise ratio and video dropouts to measurements of carrier-to-noise ratio (in a 30 kHz bandwidth) and bit error rate. Although these measurements are useful, they do not present a complete picture of system performance. For example, the carrier-to-noise ratio does not give information about intersymbol interference, and the bit error rate does not give an indication of how close to failure the system may be, i.e., how much phase margin remains. There exists a powerful method known as phase margin analysis that has been effectively used for the diagnosis of head-disk interfaces in magnetics technology.1 The technique essentially consists of measuring the bit error rate as a function of decoder window width relative to the bit cell. This information fully characterizes the channel performance, combining the effects of wide-band signal-to-noise ratio, intersymbol interference, and "hard" and "soft" defects in one easily read display.
Systematic Phase Transformation Kinetics Measurements -Crystallization and Critical Quench Rates of The Binary Te-Ge System
Authors: Rubin K. A. , Barton R. , Chen M.
Published: February 2023

Phase-change optical recording requires media which can be reversibly transformed between the amorphous and crystalline states. Previous workers have described the laser pulse conditions which cause amorphization or crystallization of thin film alloys to occur 1-5. We have continued to develop the technique which we call Phase Transformation Kinetics (PTK), which extends the previous work significantly6. A single PTK diagram shows the laser pulse conditions which cause phase transformations to occur. It is used to quantitatively compare the transformation kinetics of different materials.
Optical Head for Magneto-optical Disk Evaluation
Authors: Fujita T. , Kondo M. , Kime K. , Tomikawa N. , Takeshita N.
Published: February 2023

In this paper we report an optical head developed for measuring characteristics of magneto-optical disks. The features of this head are followings:-

(1) Collimating system without anamorphic elements.

(2) Small phase retardation in signal-readout optical system.

(3) Differential readout method using two photodetectors.
GaAlAs Window Laser with High CW Output Powers
Authors: Ungar J. , Bar-Chaim N. , Ury I.
Published: February 2023

Index guided GaAlAs laser diodes capable of providing high output powers with good beam quality are desirable for applications such as optical storage and printing. Unfortunately, the output powers of most such devices are limited to several milliwatts because of catastrophic optical mirror damage (COMD), caused by absorption of the laser output, which can exceed several MW/cm2 in intensity, at the facet. One can increase the stripe width, thereby lowering the output intensity for given overall power, as is done in such structures as the channelled substrate planar (CSP), but beyond a certain stripe width the lasing mode becomes non-fundamental, resulting in a multilobed output beam. In addition, operation close to the COMD level causes sharp degradation in reliability.
Development of Optical Disk Architecture
Authors: Stone S. H. , Girbovan E. S.
Published: February 2023

Magnetic data disks have been widely in use in computer systems since the 1960s. During this period, the disks have become smaller is size as the density of the data on the media has increased. During the last 25 years the data density has increased from 2,000 bits per square inch (IBM 350) to an estimated 24 million bits per square inch on the recently announced models of the IBM 3380.
Magnetic Properties of CoGdTb Thin Films for Thermo-Magnetic/Magneto-Optic Recording
Authors: Hairston D.K. , Kryder M.H.
Published: February 2023

Amorphous CoGd films proposed for magneto-optic recording1 lack sufficient coercivity, HC, to support sub-micron domains. Amorphous CoGdTb films having low Tb substitution and prepared by r.f. sputtering have magnetic properties similar to CoGd films2. However CoGdTb films have increased HC enabling them to support submicron domains3, 4. CoGdTb films were prepared under a variety of sputtering conditions and characterized for their thermomagnetic/magneto-optic recording application. The influence of substrate bias voltage, VBias, and argon partial pressure, PAr, used during fabrication were determined.
Photoelastic Modulated Ellipsometry on Magneto Optic Multilayer Films
Authors: Sprokel G. J.
Published: February 2023

Ellipsometry yields information on the phase difference, Δ, between the s- and p- waves after reflection and the ratio of the Fresnel coefficients, tanα = rs/rp. From these the permittivity can be determined. The experimental technique is greatly improved by using phase modulated incident light (Jasperson 1969). If the film contains a magneto optic layer the reflectivity matrix is a 2x2 complex matrix (Sprokel 1984) and the phase shift caused by the Kerr effect becomes mixed with the phase shift caused by reflection. One way to differentiate between the two is to reconfigure the ellipsometer for normal incidence. Then the reflectivity matrix is skew-symmetric and the phase shift caused by reflection is cancelled. However, exact normal incidence cannot be achieved leaving some residual error and reassembling the instrument is at best time consuming. Careful analysis of the reflectivity matrix shows that the two effects, the phase shift due to reflection and the phase shift caused by the Kerr effect, can be separated by selecting the angle of the analyzer - a Wollaston prism - at any angle of incidence. The mathematical details will be described, here we summarize the results and provide one example for a simple FeTb/SiO2 film. The optics is shown schematically in Figure 1. The modulator is a commercial unit operating at 50 kHz. The intensities I1 and I2 of the two beams exiting from the Wollaston are measured using matched photo detectors. The difference ΔI = I1 - I2 and the sum ΣI = I1 + I2 are obtained electronically. The information is contained in the modulation of ΔI and ΣI and is most conveniently obtained using a Fourier Transform technique.
An Optical Recording Disk Using an Organic Dye Medium
Authors: Ogoshi Kunizoh , Matsui Fumio , Suzuki Tsutomu , Yamamoto Takeo
Published: February 2023

Many organic dyes have been proposed as a recording media for Optical Digital Data Disks. It was found that a water-insoluble cyanine dye has excellent properties as an optical recording medium. Some of the properties of the cyanine dye for that purpose are as follows.
Research Activities on Materials for Wavelength-Multiplexed Optical Recording in Japan
Authors: Itoh Uichi , Tani Toshiro
Published: February 2023

Persistent spectral hole burning is essentially a different time two-photon process (burning process by the first photon and observation process by the second one). Various non-radiative phenomena may proceed between each photon process and even within the first one (burning). This makes the phenomena fairly complicated to understand. For instance, the holewidths observed in glass matrices are usually two or three orders of magnitude larger than those (twice of 1/T2) estimated from the simple phenomenological line shape theory1). It is considered so far that this is mainly due to the non-equilibrium nature of the disordered matrices.
Data Integrity in the LD1200 System
Authors: Lou D. Y.
Published: February 2023

Optical write once systems store data at areal densities of 105 to 106 bits/mm2 for more than 10 to 20 years. Both drives and media have flaws, and sophisticated data integrity procedures are used to insure that recorded data can be recovered correctly. This paper discusses some of the techniques implemented in Optical Storage International's LD1200 System.
Head Media Interface Tolerancing Kodak Optical Head & Kodak LWR Media
Authors: Miceli Joseph J. , Chase Scott B. , Gerger Scott A.
Published: February 2023

Kodak's 14" optical disk drive uses Run-Length-Limited (RLL) encoding techniques to increase the in-track packing density. In a pulse length encoding scheme using RLL codes, the clock and data are encoded in the mark edges and not in the mark itself. The use of such encoding schemes allows an increase in the in-track density over pulse position encoding techniques. The price of using this technique is that the CNR and linearity of the media must be consistent and of high quality.
The Influence of Melt Viscosity on the Writing Sensitivity of Organic Dye-Binder Optical-Disk Recording Media
Authors: Molaire M. F.
Published: February 2023

The object of this work was to determine the relationship between writing sensitivity of organic dye-binder media and media melt viscosity. Writing sensitivity was defined as the recording response against writing laser power. That response was measured by the electronic readout of the recorded pits. As a theoretical framework, the mechanism of hole formation espoused by Wrobel et al. (1) was assumed. That is, pit formation was considered to be essentially a flow process in which the primary driving force is back pressure due to limited material ablation and decomposition. Thus it was believed that diffusion processes were unimportant; consequently, the glass-transition temperature was not expected to be a controlling parameter. As theorized by Kivits et al. (2), it was assumed that friction forces due to viscosity had to be overcome for pit formation. This work was not concerned with the influence of optical efficiency. The work of Howe and Wrobel (3) for optimizing the dye-binder layer for optimum optical performance has been followed.
Status of m/o erasable media production
Authors: Gardner R. N. , Hailing V. W. , Rinehart T. A. , Funkenbusch A. W. , Khan M. A. , Siitari D. W. , Freese R. P.
Published: February 2023

Media product development and media scale-up activities are reviewed. Key aspects of the dynamical and mechanical characteristics of magneto-optic erasable media produced in the 3M scale-up line are discussed. The first generation product at this time is marketplace ready.
Magnetic Properties and Structural Characterization of Fe/Tb Multilayers*
Authors: Bennett Wayne R. , Person Donald C. , Falco Charles M.
Published: February 2023

Amorphous ferrimagnetic rare-earth transition metal (RETM) thin films are considered to be potential candidate materials for magneto-optic (MO) recording applications [1-3]. These films are grown to have a perpendicular uniaxial anisotropy, such that the net magnetization lies normal to the film plane [4,5]. Recently, investigators have reported superior magnetic properties for artificially layered RETM structures grown by dc-sputtering [6].
Methods of Determining Thin Film Stress for Optical Data Storage
Authors: Thomas N. L.
Published: February 2023

Thin film stress plays an important role in the manufacture of optical data disks which have a rather low aspect ratio and are very susceptible to deformation. The stress parameter has been shown to be adjustable by varying deposition parameters. More recently, ion assisted reactive evaporation is a deposition technique which has been shown to be useful in controlling stress. The successful application of these techniques requires that that the stress be monitored in situ during the coating process, or by means of a stress monitor disk which is piggybacked in the coating run and measured afterward, or on a sample data disk from the coating run.
Noise Sources in Magneto-optical Recording
Authors: Finkelstein B. I. , Williams W. C.
Published: February 2023

In data recording, the uncorrected (raw) data reliability is determined by the recording system' signal-to-noise ratio (SNR) and the size and distribution of media defects. This paper characterizes the noise sources present in magneto-optical (MO) recording systems. By identifying and quantifying these noise sources, system performance can be optimized.
Magneto-Optic Compensator for MO Disk Substrate Birefringence
Authors: Revelli Joseph F. , Perry Stuart D. , Stinson Douglas G.
Published: February 2023

Injection-molding techniques employed in the fabrication of polymer substrates used in magneto-optic disks introduce stress-induced birefringence. This birefringence, which varies from point to point on the disk, results in a low-frequency noise component to the signal available in the detection of magneto-optically stored data. This paper describes a method, based on the use of a variable-angle Faraday rotator, for compensating for the substrate birefringence. It should be pointed out that the following method is predicated on the assumptions that a) vertical birefingence can be ignored, and b) the in-plane birefringence axes are oriented along the disk radial and tangential axes at each point on the disk. Although it is realized that the vertical birefringence component cannot in general be ignored,1 the compensation presently described should improve the signal-to-noise ratio.
Recent Advances In Phase-Change Media
Authors: Tyan Y.-S. , Pan K. C. , Preuss D. R. , Olin G. R. , Vazan F.
Published: February 2023

Phase-change media, utilizing the switching between amorphous states and crystalline states induced by the heating of a focused laser beam for information storage, have been the subject of research for many years. The major challenge is to develop materials having appropriate crystallization kinetics so that the amorphous state can be crystallized in a matter of nanoseconds under the influence of the heating laser beam and yet remain stable at operating and keeping temperatures. For erasable operation, the kinetics should also allow the quenching of the material from the molten state produced by the heating laser beam into the amorphous state. This requires the crystallization rate at just below the melting point to fall within a narrow range determined by the maximum crystallization rate allowed by practical considerations and the cooling rate of the media.
Advanced Technologies for the Next Generation Optical Disks
Authors: Tsunoda Yoshito , Ojima Masahiro
Published: February 2023

Application areas of optical disk systems have been expanding slowly but stably into the market during these few years. So far optical disks systems are widely used for image and document data storage. This application area is thought to be the most appropriate for the present performances and the functions of optical disks. One of the biggest limiting factor of the present optical disks for applying to directly competitive market with the conventional magnetic disk storage systems is their slow data processing time including data transfer rate, accessing time, and disk rotaion time. These problems have to be solved in order to apply optical disks to more general application areas where conventional magnetic disk storage systems are widely used.
Photochemical Hole Burning of Tetraphenylporphine Derivatives.
Authors: Kishii N. , Tamura S. , Asai N. , Kawasumi K. , Seto J.
Published: February 2023

Photochemical hole burning (PHB) is promising as a crucial technology for an ultra-high density optical storage system, and as many as 103 or more bits may be stored in a single focused laser spot[l,2]. A practical frequency domain storage system requires the development of new recording material systems with high sensitivity and good hole properties.
Tracking Error Signal Analysis for Pre-Grooved Organic Optical Recording Media
Authors: Suh S. Y. , Onorato F. J. , Chiang K.
Published: February 2023

Experimental measurements and theoretical computation presented in this paper indicate that for optimal tracking error signals organic based media require grooves that are narrower and deeper than those required for metallic based media.
Rare-earth hexaboride reflector layers to enhance Kerr rotation in magneto-optical [MO] storage media
Authors: Balasubramanian K. , Macleod H. A.
Published: February 2023

Kerr rotation enhancement is important for improving the SNR in MO media. Here, for the first time, we discuss with illustrations the effectiveness of rare-earth hexaboride reflector layers to enhance the Kerr rotation.
Small form factor magneto-optic disk drives
Authors: Sander Ingolf
Published: February 2023

The development of optical storage devices is following the trend in magnetic recording to smaller form factors from 14" to 12", 8", 5 1/4" to 3 1/2" and 2 1/2 ".
Full-Height Magneto-Optic Rewritable Disk Drive
Authors: Murakami Teruo , Ando Hideo , Yana Masasumi
Published: February 2023

The authors have developed a 130 mm magneto-optic (MO) rewritable disk drive. This drive is 146W*203D*82H mm in size, which is as small as the so-called full-height, size 5.25 inch magnetic disk drive, and conforms to the 130 mm rewritable disk ISO standard.
Overwrite Technology for Magneto-optic Disk
Authors: Imamura Nobutake
Published: February 2023

Developments of overwrite technology are reviewed. There are three typical methods, they are magnetic field modulation, laser beam intesity modulation and multi-beam method.
40 dB Overwrite-Modulation Phase—Change Optical Disk Using In-Sb-Te Alloy
Authors: Sato Yoshio , Maeda Yoshihito , Andoh Hisashi , Ikuta Isao , Nagai Masaichi , Tsuboi Nobuyoshi , Minemura Hiroyuki , Ishigaki Masaharu
Published: February 2023

A single-beam overwrite was achieved by an In-Sb-Te phase-change optical disk. The carrier to noise (C/N) ratio of more than 50 dB and the overwrite modulation of -40 dB were obtained for overwriting frequencies of 2 MHz and 3 MHz using a low power laser diode of 30 mW. The high C/N ratio and the excellent overwrite modulation were due to the large reflectivity difference between the written and erased phases and the use of suitable write/erase power.
Flexible Optical Drive Technology
Authors: Perera S. Robert
Published: February 2023

Bernoulli technology is named after the 18th century Swiss mathematician of that name who first expressed the principles of fluid technology, which imply that when the air above a surface moves faster than the air below, it causes "lift" on that surface - as with an airplane wing. This principle is the basis of the Bernoulli Optical Systems (BOSCO) drive.
Polarization Properties of High Numerical Aperture Holographic Objectives
Authors: O'Connor A. Bruce , Kostuk Raymond K.
Published: February 2023

Holographic elements have been demonstrated as practical alternatives to refractive optics in head designs for compact disk (CD) players and write once read many (WORM) drives.1 These elements are attractive alternatives to refractive components because they can be formed in thin film emulsions, are light weight, and can combine several optical functions in a single element. The extension of holographic elements to magneto-optic (MO) head designs requires an understanding of their polarization properties. In this presentation we will discuss the results of a study of the polarization properties of high numerical aperture (N.A.) holographic focusing elements.
Effect of Birefringence in Polycarbonate Substrates on Dynamic Performance of Magnetooptical Disks
Authors: Shin Sung-Chul , Greener Jehuda , Pratt Thomas L. , Kesel Raymond
Published: February 2023

The effect of birefringence in polycarbonate substrates on the dynamic performance of magnetooptical disks has been investigated. We have observed a monotonic decrease of the carrier-to-noise ratio with increase in the normal retardation for retardation levels greater than about 15 nm.
Accelerated Aging Studies for Polycarbonate Optical Disk Substrates
Authors: Nikles David E. , Forbes Charles E.
Published: February 2023

Accelerated aging studies have been reported2,3 on a write-once read-many optical data storage medium, based on proprietary naphthalocyanine recording layer materials. In the course of that work, it was observed that the polycarbonate substrates become brittle after exposure to 80°C and 80% relative humidity. Earlier, Bair et al.4 reported that, upon exposure to 85°C and 96% relative humidity for 720 hr, polycarbonate hydrolyzed to give brown surface crystals of bisphenol A monomer. Such hydrolysis for polycarbonate substrates could lead to catastrophic failure for optical disks, regardless of the stability for the recording layer. In this paper, accelerated aging studies for polycarbonate optical disk substrates are reported. The purpose of this study was to ascertain whether polycarbonate optical disk substrates degrade under conditions used to study the accelerated aging of optical disks.
Directly Overwritable Magneto-Optical Disk with Light Power Modulation Method Using No Initializing Magnet
Authors: Tsutsumi Kazuhiko
Published: February 2023

The direct overwrite technology is one of the most important subjects for achieving a high data transfer rate for the magneto-optical recording system. Several overwrite technologies have been proposed [1]-[3]. The light power modulated overwriting was successfully reported by Saito et al. [2] using an exchange coupled double layer film. It is thought to be the most reliable direct overwrite method, however in addition to a conventinal bias magnet, it needs an initializing magnet which produces a large magnetic field. The initializing magnet makes the drive large and complicated. We have shown the exchange coupled RE-TM quadrilayered film is overwritable with light power modulation using no initializing magnet [4]. This method does not need the initializing magnet because the film has layers which play the same role as the initializing magnet
Enumerative Modulation Coding with Arbitrary Constraints and Post-Modulation Error Correction Coding for Data Storage Systems
Authors: Mansuripur M.
Published: February 2023

The use of modulation codes in magnetic and optical data storage systems is widespread and the advantages of modulation coding are well known [1-3]. Usually a 1 is used to represent a transition between the up and down states of the recording waveform, while a 0 represents no change. An unconstrained sequence of l's and 0's, however, is not acceptable, nor is it desirable, in practice. The objective of modulation coding is to create a one-to-one correspondence between sequences of user data (which are usually streams of random binary digits) and constrained binary sequences. The nature of the constraints imposed on the modulated signal must be determined by the system designer and is dependent on the particular characteristics of the system under consideration. A typical set of such restrictions is the so-called (d,k;c) constraint. Here d is the minimum allowed run-length of zeros, k is the maximum allowed run-length of zeros, and c is the maximum charge that the recording waveform is permitted to accumulate. In addition, certain sequences of bits may be reserved for special purposes (such as synchronization or signaling the beginning of a block) and thus banned from appearing in the modulated waveform.
90mm Magneto-Optical Disk Drive With Digital Servo
Authors: Miyoshi Masahiro , Kawasaki Tetsuharu , Takahashi Satoru , Mine Hironori
Published: February 2023

As personal computers and OA machines with higer level functions continue decrease in size recently, the requirements for external storage devices are becoming exacting. The 130mm magneto-optical disk drives presently used cannot necessarily meet those requirements. We have developed a 90mm magneto-optical disk drive, aiming at higher performance, small size and lower power dissipation, as well as higher reliability. The target of lower power dissipation is important in order to prevent a rise in temperature inside the drive, to realize higher-density packaging and to decrease the quantity of cooling airflow which causes the accumulation of dust.
Two-photon 3-D optical memories
Authors: Esener Sadik , Rentzepis P. M.
Published: February 2023

An optical volume memory based on two photon effect providing high storage density and memory bandwidth is described. Preliminary experimental data is presented.
Erasable Phase Change Media
Authors: Ohta Takeo
Published: February 2023

We found two key attributes of cycle stability for phase change erasable disc media. One is nitrogen modified active layer of GeTe-Sb2Te3-Sb system. The other is the combination of dielectric material of ZnS-SiO2 mixture and SiO2.

The disc media having the modified active layer and ZnS-SiO2 dielectric layer show wide tolerance for laser power and long life of more than 60 years. New disc construction shows two million overwrite cycle stability of BER characteristics.
High-Performance Optical Disk Systems for Tactical Applications
Authors: Haritatos Fred
Published: February 2023

The Rome Air Development Center (RADC) has been actively pursuing the development and transition of optical disk storage technology from the laboratory into the real world environment. A considerable investment of R&D resources has been made by the Department of Defense with an emphasis on the development of highcapacity, high-performance systems.
A MultiTrack Rewritable Optical Disk Recording System for High Performance Applications: 14-inch TODS
Authors: Cinelli Joseph , Kozak Taras
Published: February 2023

GE has been developing high performance recording systems for ruggedized and militarized applications, covering spaceborne, airborne, shipboard and mobile applications. Through sponsorship of the Air Force's Rome Air Development Center (RADC), the 14-inch Tactical Optical Disk System (TODS) is currently being designed and built for reconnaisance aircraft applications. These applications require real time data capture and online storage of large image and sensor database files, which must be stored and retreived rapidly. This requirement translates into high performance system specifications for the 14-inch TODS optical disk storage system. Of primary concern is high, continuous data transfer rates and large data storage capacities. Large image files cannot be segmented, thus requiring the system to contain the entire data file on a single media unit, and to stream the file at a very high data transfer rate.
Integrated Reading and Writing Magneto Optical Heads A Way to a Multigigabyte Multi-rigid-disk Drive
Authors: Renard Stephane , Valette Serge
Published: February 2023

Magneto-Optical (MO) disk drives hold some winning cards to fight against Winchester drives: - huge bit densities - removable cartridges. But most analyses conclude that MO disks will overthrow magnetic disks in the field of data storage devices only when they will be competitive on other characteristics such as : - direct overwriting - access times - data transfert rate.
Flying Head Read/Write Characteristics Using a Monolithically Integrated LD-PD at a Wavelength of 1.3 µm
Authors: Ukita Hiroo , Nakada Hiroshi , Katagiri Yoshitada
Published: February 2023

The LD-PD(1) is an oxidation-free, 1.3 µm wavelength InGaAsP laser diode monolithically integrated with a photodetector. A flying optical head(2) with an LD-PD on a slider is expected to be smaller, lighter, and less expensive than the conventional heads. In this paper, we analyze the read/write characteristics, the head/disk interface reliability, and the expected applications of the proposed head.
Micro-optic lens for data storage
Authors: Milster Tom D. , Trusty Robert M. , Wang Mark S. , Froehlich Fred F. , Erwin J. Kevin
Published: February 2023

There are several types of micro lenses commonly used in optical data storage systems. The most common are molded glass and molded plastic lenses. Molded optics weigh less than conventional multiple-element designs. Typical apertures are 3.5mm to 4.5mm in diameter, and numerical apertures (NAs) range from 0.45 to 0.55. For optical data storage applications, the smallest molded micro lenses available have an entrance pupil diameter (d) of 3.0mm. (1) There are several reasons to use smaller optics. If a smaller micro lens is used as an objective lens, the same number of disks can fit into a smaller stack height, and volumetric storage density will increase. If all hardware dimensions scale linearly with optics size, a reduction in lens size by some factor will allow a reduction in moving mass by that factor to the third power, since mass scales with volume. The result will be an improvement in access time.