Communication to application developers and data users of CD-R characteristics such as data integrity, media reliability and life expectancy should be considered as engineers create opticalstorage media that can stor...
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ISBN:
(纸本)081943292X
Communication to application developers and data users of CD-R characteristics such as data integrity, media reliability and life expectancy should be considered as engineers create opticalstorage media that can store more data. Though the point of view of this paper is primarily based on the views of a few experienced CD-R end-users, optical engineers should consider implementation of the following design recommendations explained in this paper. The authors' extensive experience in using CD-R technology and their substantial interaction with other CD-R users provides a rare perspective on CD-R characteristic information. Although this paper is directed to optical engineers, it is written with the expectation that a broader readership will also benefit from the information presented. The paper presents to the engineering community potential methods of communicating CD-R characteristics with an emphasis on the types of information that would be useful to CD-R users.
We have developed a wide-area-distributed storage system for multimedia databases that minimizes the possibility of simultaneous failure of multiple disks in the event of a major disaster. It features a RAID system wh...
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We have developed a wide-area-distributed storage system for multimedia databases that minimizes the possibility of simultaneous failure of multiple disks in the event of a major disaster. It features a RAID system whose member disks are spatially distributed over a wide area. Each node has a device that includes the controller of the RAID and the controller of the member disks controlled by other nodes. The devices in the node are connected to a computer using fiber optic cables and communicate using Fibre-Channel technology. Any computer at a node can utilize multiple devices connected by optical fibers as a single 'virtual disk'. The advantage of this system structure is that devices and fiber optic cables are shared by the computers. In this report, we first describe our proposed system and a prototype we used for testing. Then we discuss its performance, i.e., how the read and write throughputs are affected by data-access delay, the RAID level, and queuing.
A polychromatic versatile dynamic testbed for the evaluation of optical disks is presented. The system can be used for all wavelengths from 400 to 690(780) nm, allowing any laser source in this range - especially the ...
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ISBN:
(纸本)081943292X
A polychromatic versatile dynamic testbed for the evaluation of optical disks is presented. The system can be used for all wavelengths from 400 to 690(780) nm, allowing any laser source in this range - especially the new blue laser diodes - to be utilized for read-write-erase experiments. In addition, the system allows testing of disk with substrate thicknesses ranging from 0 to 1.7 mm. The polarization of the system can easily be changed from linear to circular at the disk surface, so the use of both magneto-optical (MO) and phase-change disks (PD) is possible, in addition to read-only disks (CD, DVD). A variable leaky polarizing beam splitter has been specially designed for this tester. This device allows to continuously adjust the ratio between the s- and p- polarized components for the reflected beam reaching the detectors, enabling the optimization of the signal-to-noise ratio while adjusting the relative amounts of the two components of polarization at the detectors. The astigmatic method is used far focus control and the push-pull method is used for track control (other focusing and tracking schemes like DPD are under preparation). In a optional setup, the RF data signal and the focus and track servo signals can be derived from the same high speed quad detectors, allowing the use of the full optical power returning of the disk for all these purposes. So the astigmatic FES, the push-pull TES, the differential magneto-optical readout signal and the conventional sum signal for phase-change readout as well as the differential edge-signal for mark-edge detection are obtained. In this paper, we are presenting the basic functions of VERSATEST-I as well as future enhancements for latest opticaldatastoragetechnology. Additionally typical test results on magneto-optical disks and phase-change disks (DVD-RAM 5.2GB) are reported.
A variety of CD and DVD recordable and rewritable disc formats have or shortly will transition into mass market products. Apart from the inherent manufacturing complexity, this development has created very demanding r...
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A variety of CD and DVD recordable and rewritable disc formats have or shortly will transition into mass market products. Apart from the inherent manufacturing complexity, this development has created very demanding requirements on unit manufacturing cost, production yields, and quality. The dynamic storage marketplace has placed additional, constantly evolving demands on product capabilities. All of this is reflected in the current approach to optical disc manufacturing equipment through their emphasis on modularity, flexibility, and upgradeability. The developments in the CD-R arena encapsulate and serve to highlight these issues and will be used as a case study.
An intercomparison of optical disc birefringence measurements using commercial instrumentation found in manufacturing settings showed significant measurement variation. We discuss possible sources of variation in thes...
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An intercomparison of optical disc birefringence measurements using commercial instrumentation found in manufacturing settings showed significant measurement variation. We discuss possible sources of variation in these measurements, including changes in disc properties and coherence effects. We describe specific measurement errors related to deviations from circular input polarization in one class of polarimetric instruments. Efforts to mitigate measurement errors, such as the development of calibration artifacts, are discussed.
One of interesting applications of two dimensional VCSEL arrays is high density opticaldatastorage. We proposed a micro-metal aperture VCSEL for producing optical near-field. The evanescent wave emitted from a small...
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ISBN:
(纸本)0819435015
One of interesting applications of two dimensional VCSEL arrays is high density opticaldatastorage. We proposed a micro-metal aperture VCSEL for producing optical near-field. The evanescent wave emitted from a small metal aperture formed on a VCSEL surface is irradiated to an optical disk, such as a phase change optical disk. We carried out a near-field analysis on the radiation from the metal micro aperture loaded on a VCSEL by using 2-dimensional finite element method (FEM), showing a possibility of a spot size of below 100 nm. We can recycle the reflected wave from the metal aperture, when we properly design the phase matching between the DBR mirror and the metal. We can expect an improvement in a power conversion efficiency of radiating near field light from the aperture by using a "photon recycling" effect. An expected efficiency and power density are discussed for 850 nm metal aperture VCSELs. We have fabricated micro-metal aperture VCSELs by using focus ion beam etching. The size of the fabricated apertures ranges from 100 nm and 400 nm. We have realized sub-mA low threshold metal aperture VCSELs. The power density is estimated to be similar to 6 kW/cm(2). We will be able to improve the power density by reducing the oxide aperture in the cavity. We also discuss on another way to increase the efficiency and the power density, such as using a surface plasmon effect of a small metal tip formed on the surface. We will discuss a possibility of optical near-field recording by using the proposed metal aperture VCSEL.
A method for rapid characterization of DVD multilayer depositions is presented. With a single optical measurement the devised method allows to determine the values of the refractive index (n) and of the extinction coe...
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A method for rapid characterization of DVD multilayer depositions is presented. With a single optical measurement the devised method allows to determine the values of the refractive index (n) and of the extinction coefficient (k) for the wavelength comprised between 400 and 900 nm, and the film thickness. The analysis of these optical and physical properties provides a mean for tracking back possible process deviations in the multilayer sputtering of the DVD-RAM disks.
The paper introduces characters of Near Field optical Disc (NFOD) Recording Technique. The paper presents electrical and optical waveguide process problems in corn-shaped optical head of NFOD. it also put forward to t...
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The paper introduces characters of Near Field optical Disc (NFOD) Recording Technique. The paper presents electrical and optical waveguide process problems in corn-shaped optical head of NFOD. it also put forward to the three grades approximate model of ultra-small-size laser firstly and simulate calculations in first-grade approximation of corn-shaped optical head of NFOD. The result give the relation between laser's input current and output power and the near field output light intensity pattern, and it is an important basis for the NFOD optical head design with ultra thin active layer and ultra small spot laser.
The method to measure the apparent reflectivity with gloss meter is applied to the phase-change optical disks before and after initialization process. The apparent reflectivity measurements for relative large area and...
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The method to measure the apparent reflectivity with gloss meter is applied to the phase-change optical disks before and after initialization process. The apparent reflectivity measurements for relative large area and the reflectivity measured by optical pick-up are compared. The apparent reflectivity measurements are proven to enough for the characterization of recording layer. The measurement with gloss meter has several advantages of speed, simple structure, low price and etc.
data archivists expect information storage media to have a lifetime greater than ten years. Furthermore they desire the ability to predict when the media will fail in order to plan for its replacement. Archival lifeti...
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data archivists expect information storage media to have a lifetime greater than ten years. Furthermore they desire the ability to predict when the media will fail in order to plan for its replacement. Archival lifetime predictions are based on accelerated aging studies, where the media are subjected to conditions of high temperature and high humidity. The rate of failure is measured and the data extrapolated to obtain rates of failure under ambient conditions. This extrapolation is reasonable provided the degradation process is activated and the Arrhenius relationship holds. However this may not be the case for the complicated materials packages in opticaldatastorage media. A primary concern for the polymeric materials is any phase transition, such a glass transition or a beta relaxation, that may occur at temperatures between ambient and the accelerated aging conditions. It is not clear how one extrapolates through those transitions. These phase transitions can give rise to large changes in the rates of diffusion for water, oxygen and other agents of degradation. Furthermore, for polymers, such as polycarbonate, the mode of failure is often hydrolysis and the degradation products can catalyze further hydrolysis, an autocatalytic degradation. The polymer degradation will change the phase transition temperatures. The degradation products may also plasticize the polymer, causing further changes in diffusion rates. We provide here a simple analysis of accelerated aging techniques and discuss other factors that may be involved.
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