Information stored on magneto-optic disks is typically read using a linearly polarized laser beam whose state of polarization is altered by the Faraday and/or polar Kerr effects upon reflection from the recording medium. Polarization sensitive optics are used to convert these media induced polarization changes into irradiance variations at photodetectors. Because the magneto-optic polarization effects are small (typically less than one degree of polarization rotation in the reflected beam) it is essential that the optical system introduce little additional polarization change if the recorded signal is to be recovered faithfully. This paper describes a polarization model that is used to predict the effects that real optical elements will have on the readout signals, noise, and ultimately, the signal to noise ratio of a magneto-optic recording system.
{"title":"A Magneto-optic Polarization Readout Model","authors":"D. Campbell, D. Towner","doi":"10.1364/ods.1985.tubb2","DOIUrl":"https://doi.org/10.1364/ods.1985.tubb2","url":null,"abstract":"Information stored on magneto-optic disks is typically read using a linearly polarized laser beam whose state of polarization is altered by the Faraday and/or polar Kerr effects upon reflection from the recording medium. Polarization sensitive optics are used to convert these media induced polarization changes into irradiance variations at photodetectors. Because the magneto-optic polarization effects are small (typically less than one degree of polarization rotation in the reflected beam) it is essential that the optical system introduce little additional polarization change if the recorded signal is to be recovered faithfully. This paper describes a polarization model that is used to predict the effects that real optical elements will have on the readout signals, noise, and ultimately, the signal to noise ratio of a magneto-optic recording system.","PeriodicalId":268493,"journal":{"name":"Topical Meeting on Optical Data Storage","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122172668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The success of any product intended for use as a high capacity digital storage medium depends critically on the quality control procedures adopted during manufacture. This requires that simple test methods which can be routinely applied during volume manufacture should be developed. The Plasmon disc is unique in its construction and lends itself to simple monitoring which can be used not only to control the Moth Eye texture but to provide invaluable data on the satisfactory operation of all stages in the production process..
{"title":"Volume Production of Plasmon Optical Discs","authors":"K. Gardner, PR Helfet, RJ Longman","doi":"10.1364/ods.1985.wdd5","DOIUrl":"https://doi.org/10.1364/ods.1985.wdd5","url":null,"abstract":"The success of any product intended for use as a high capacity digital storage medium depends critically on the quality control procedures adopted during manufacture. This requires that simple test methods which can be routinely applied during volume manufacture should be developed. The Plasmon disc is unique in its construction and lends itself to simple monitoring which can be used not only to control the Moth Eye texture but to provide invaluable data on the satisfactory operation of all stages in the production process..","PeriodicalId":268493,"journal":{"name":"Topical Meeting on Optical Data Storage","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115049056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This presentation addresses many hardware aspects of the Storage Technology 7640 Optical Storage Unit, concentrating on Mechanics, Optics, Servomechanics, and Read/Write characteristics.
本报告介绍了存储技术7640光存储单元的许多硬件方面，集中在力学、光学、伺服力学和读/写特性。
{"title":"An Overview of 7640 Storage Technology*","authors":"K. J. Stahl","doi":"10.1364/ods.1984.wca1","DOIUrl":"https://doi.org/10.1364/ods.1984.wca1","url":null,"abstract":"This presentation addresses many hardware aspects of the Storage Technology 7640 Optical Storage Unit, concentrating on Mechanics, Optics, Servomechanics, and Read/Write characteristics.","PeriodicalId":268493,"journal":{"name":"Topical Meeting on Optical Data Storage","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122721961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The bit-error-rate (BER) performance of well designed Optical Disk Recording Systems, like their magnetic recorder predecessors, depends on how well the media error model is known and how compatibly the recorder error management system is designed. The use of diffraction limited, argon laser spots to write and read has led to implementations with high linear packing densities (80 KBPI) and very high track pitches (1.0 um). With this high areal packing density, small defects mask many bits over a number of tracks. An additional complexity is that media tuned for use at the argon wavelengths is not yet commercially available. These factors force the system designer to implement a flexible error management system which can be tailored to the media defect distribution as the media evolves.
{"title":"A Measured Optical Disk Media Error Model and a Compatible Error Management Implementation","authors":"J. H. Hoover, J. Waring","doi":"10.1364/ods.1984.wcc5","DOIUrl":"https://doi.org/10.1364/ods.1984.wcc5","url":null,"abstract":"The bit-error-rate (BER) performance of well designed Optical Disk Recording Systems, like their magnetic recorder predecessors, depends on how well the media error model is known and how compatibly the recorder error management system is designed. The use of diffraction limited, argon laser spots to write and read has led to implementations with high linear packing densities (80 KBPI) and very high track pitches (1.0 um). With this high areal packing density, small defects mask many bits over a number of tracks. An additional complexity is that media tuned for use at the argon wavelengths is not yet commercially available. These factors force the system designer to implement a flexible error management system which can be tailored to the media defect distribution as the media evolves.","PeriodicalId":268493,"journal":{"name":"Topical Meeting on Optical Data Storage","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128946844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The problems of dust contamination of an initially clean optical disk can be alleviated by sealing the recording surface beneath a transparent protective layer. Overcoats, transparent substrates, and air-spaced cover sheets can be used to keep small particles out of the focal range of the objective lens and minimize their optical effects. The intrinsic optical properties required by such cover-sheet layers have been described.1 The purpose of this study is to determine the minimum layer thickness (or cover-sheet spacing) necessary to provide reliable optical isolation of dust on the surface of an optical disk.
{"title":"Cover Sheets for Dust Protection","authors":"A. Marchant","doi":"10.1364/ods.1984.fca4","DOIUrl":"https://doi.org/10.1364/ods.1984.fca4","url":null,"abstract":"The problems of dust contamination of an initially clean optical disk can be alleviated by sealing the recording surface beneath a transparent protective layer. Overcoats, transparent substrates, and air-spaced cover sheets can be used to keep small particles out of the focal range of the objective lens and minimize their optical effects. The intrinsic optical properties required by such cover-sheet layers have been described.1 The purpose of this study is to determine the minimum layer thickness (or cover-sheet spacing) necessary to provide reliable optical isolation of dust on the surface of an optical disk.","PeriodicalId":268493,"journal":{"name":"Topical Meeting on Optical Data Storage","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125387538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Onisawa, S. Tokuhara, Taiji Hiramatsu, Hirotaka Toba
Polymethylmethacrylate(PMMA) and Polycarbonate(PC) was usually used for the materials for the substrate of optical disks. PMMA is used for the commercialized disk substrates larger than 20cm in diameter because of the excellent optical properties, especially low level of birefringence. But the substrate of PMMA has a fault, that warping takes place more easily than PC by heat and water absorption. On the other hand PC is not liable to warp but has generally poorer moldability and higher birefringence. Thus PC is used only for compact disk of 12cm diameter. PC is superior to PMMA if the birefringence can be decreased. We reported on the topical meeting at Montrey last year that 20cm diameter PC substrate with low birefringence was obtained by optimum selection of conditions for injection molding. It was possible to keep the retardation of the recordable area of PC 20cm diameter substrates within 40nm(double pass). Furthermore we investigated the molding conditions for PC 30cm diameter substrates and succeeded in molding substrates of low birefringence(retardation) as shown in Fig.1. We used a special mold which has several pressure sensors in the cavity and optimized the molding conditions, using the correlation between pressure distribution and birefringence. The environmental durability of optical disks is very important from the viewpoint of actual usage of optical disks as optical recording media. We found that the depth of tracking pregrooves engraved on plastic substrates by injection molding changes depending on environmental conditions. Generally, the substrates for optical disk have groove of submicron size. In the process of injection molding of disk substrate molten polymer is injected into mold cavity with high flow rate and pressed on the stamper by cavity pressure. Then pregrooves and pits on the stamper is replicated to molten polymer. The change of cylinder position, ram pressure and pressure of mold cavity during injection is shows in Fig.2. The time for the process from the injection of the hot molten polymer to the rise of pressure in a mold cavity is only a few milliseconds.
{"title":"Plastic Substrate for Optical Memory Disk","authors":"Y. Onisawa, S. Tokuhara, Taiji Hiramatsu, Hirotaka Toba","doi":"10.1364/ods.1985.thcc3","DOIUrl":"https://doi.org/10.1364/ods.1985.thcc3","url":null,"abstract":"Polymethylmethacrylate(PMMA) and Polycarbonate(PC) was usually used for the materials for the substrate of optical disks. PMMA is used for the commercialized disk substrates larger than 20cm in diameter because of the excellent optical properties, especially low level of birefringence. But the substrate of PMMA has a fault, that warping takes place more easily than PC by heat and water absorption. On the other hand PC is not liable to warp but has generally poorer moldability and higher birefringence. Thus PC is used only for compact disk of 12cm diameter. PC is superior to PMMA if the birefringence can be decreased. We reported on the topical meeting at Montrey last year that 20cm diameter PC substrate with low birefringence was obtained by optimum selection of conditions for injection molding. It was possible to keep the retardation of the recordable area of PC 20cm diameter substrates within 40nm(double pass). Furthermore we investigated the molding conditions for PC 30cm diameter substrates and succeeded in molding substrates of low birefringence(retardation) as shown in Fig.1. We used a special mold which has several pressure sensors in the cavity and optimized the molding conditions, using the correlation between pressure distribution and birefringence. The environmental durability of optical disks is very important from the viewpoint of actual usage of optical disks as optical recording media. We found that the depth of tracking pregrooves engraved on plastic substrates by injection molding changes depending on environmental conditions. Generally, the substrates for optical disk have groove of submicron size. In the process of injection molding of disk substrate molten polymer is injected into mold cavity with high flow rate and pressed on the stamper by cavity pressure. Then pregrooves and pits on the stamper is replicated to molten polymer. The change of cylinder position, ram pressure and pressure of mold cavity during injection is shows in Fig.2. The time for the process from the injection of the hot molten polymer to the rise of pressure in a mold cavity is only a few milliseconds.","PeriodicalId":268493,"journal":{"name":"Topical Meeting on Optical Data Storage","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128840997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As the speed and capacity of advanced military computers increase, there is a growing need for fast high density memory systems. This report will detail work done at Sperry to develop a novel read/write head which will be used in a Write Once Read Many (WORM) optical disk memory system. The disk system will be used in a digital mapping unit for a tactical fighter aircraft which has extreme operating conditions.
{"title":"Design of a Fiber Optic Read/Write Head for a Military Optical Disk System","authors":"Mark L. Wilson, B. Fritz","doi":"10.1364/ods.1987.wd4","DOIUrl":"https://doi.org/10.1364/ods.1987.wd4","url":null,"abstract":"As the speed and capacity of advanced military computers increase, there is a growing need for fast high density memory systems. This report will detail work done at Sperry to develop a novel read/write head which will be used in a Write Once Read Many (WORM) optical disk memory system. The disk system will be used in a digital mapping unit for a tactical fighter aircraft which has extreme operating conditions.","PeriodicalId":268493,"journal":{"name":"Topical Meeting on Optical Data Storage","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127889277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reversible optical information storage based on the amorphous-crystalline phase transformation has been the subject of many investigations since the early 1970’s1-8. One of the unresolved problems associated with phase-change recording media has been the need to trade off erase (crystallization) speed against data (amorphous phase) stability. For the most part, the search for viable phase-change recording material has been based on one common approach. Starting with a group VA or VIA element in the periodic table, Te being the most popular one, attempts were made to achieve the desired properties through alloying. To date, no one has published achieving a sub-microsecond erase speed along with a practical data retention period.
{"title":"New Ideas for Phase-Change Media - Achieving Sub-Microsecond Erase with Data Stability","authors":"M. Chen, K. Rubin, R. Barton","doi":"10.1364/ods.1985.pd1","DOIUrl":"https://doi.org/10.1364/ods.1985.pd1","url":null,"abstract":"Reversible optical information storage based on the amorphous-crystalline phase transformation has been the subject of many investigations since the early 1970’s1-8. One of the unresolved problems associated with phase-change recording media has been the need to trade off erase (crystallization) speed against data (amorphous phase) stability. For the most part, the search for viable phase-change recording material has been based on one common approach. Starting with a group VA or VIA element in the periodic table, Te being the most popular one, attempts were made to achieve the desired properties through alloying. To date, no one has published achieving a sub-microsecond erase speed along with a practical data retention period.","PeriodicalId":268493,"journal":{"name":"Topical Meeting on Optical Data Storage","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116499724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Textured surfaces have been studied for application to optical storage as an alternative mechanism to the conventional ablative hole-forming process. Writing process in the textured media has been shown to be inherently sensitive, because the surface energy stored on the textured column is calculated to be sufficient to accomplish the melting limited writing. This represents a significant sensitivity improvement and a great deal of simplification in the material selection.
{"title":"Signal-to-Noise Measurements on Textured Optical Storage Media","authors":"S. Suh, D. Snyder, D. L. Anderson, H. Craighead","doi":"10.1364/ods.1984.thca5","DOIUrl":"https://doi.org/10.1364/ods.1984.thca5","url":null,"abstract":"Textured surfaces have been studied for application to optical storage as an alternative mechanism to the conventional ablative hole-forming process. Writing process in the textured media has been shown to be inherently sensitive, because the surface energy stored on the textured column is calculated to be sufficient to accomplish the melting limited writing. This represents a significant sensitivity improvement and a great deal of simplification in the material selection.","PeriodicalId":268493,"journal":{"name":"Topical Meeting on Optical Data Storage","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128446424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper describes the principle and performance of a new focusing method which has high potential use for a small optical head for the DRAW-type optical disk. We named it the wax-wane method because of changes in the brightness profile of a laser on a detector.
{"title":"New Focusing Method for DRAW-Type Optical Head","authors":"S. Arai, K. Hamada, K. Ogawa","doi":"10.1364/ods.1985.thbb1","DOIUrl":"https://doi.org/10.1364/ods.1985.thbb1","url":null,"abstract":"This paper describes the principle and performance of a new focusing method which has high potential use for a small optical head for the DRAW-type optical disk. We named it the wax-wane method because of changes in the brightness profile of a laser on a detector.","PeriodicalId":268493,"journal":{"name":"Topical Meeting on Optical Data Storage","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134322137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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