F. Maeda, K. Osato, I. Ichimura, Kenji Yamamoto, A. Fukumoto, Toshio Watanabe, Mitsuo Naito, S. Masuhara
{"title":"High density optical disk system using a new two-element lens and a thin substrate disk","authors":"F. Maeda, K. Osato, I. Ichimura, Kenji Yamamoto, A. Fukumoto, Toshio Watanabe, Mitsuo Naito, S. Masuhara","doi":"10.1364/isom.1996.ofa.1","DOIUrl":"https://doi.org/10.1364/isom.1996.ofa.1","url":null,"abstract":"The areal density of an optical storage disk can be increased by improving the transverse resolution of the optical head which is proportional to λ/NA. In order to improve the resolution, a lot of research has been carried out to develop shorter wavelength light sources such as green or blue SHG lasers1,2) and recently ZnSe or GaN semiconductor blue lasers3). These lasers will soon become commercially available. On the other hand, it is difficult to make a high NA objective using a single molded aspherical element. Furthermore the higher the numerical aperture, the less the tolerance for variations in disk thickness, disk tilt, and focusing which are inversely proportional to the fourth, third, and second power of the numerical aperture, respectively. Other experiments have been carried out to improve the resolution using near-field optics4) such as scanning probes which can improve the areal density drastically, however, such probes seem to be tolerated only for working distances of around 100 nm.","PeriodicalId":322309,"journal":{"name":"Joint International Symposium on Optical Memory and Optical Data Storage","volume":"27 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":"127155927","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}
{"title":"Direct Access Compact Disc vs. CD-ROM Reliability Estimates","authors":"B. Tehranchi, D. Howe","doi":"10.1364/isom.1996.otub.20","DOIUrl":"https://doi.org/10.1364/isom.1996.otub.20","url":null,"abstract":"The Cross Interleaved Reed-Solomon Code (CIRC) used in CD-ROM for basic error correction/detection consists of two catenated, distance 5 Reed-Solomon codes. These two subcodes, which are called the C1 and C2 codes, have length 32 bytes and 28 bytes respectively. C1 and C2 can each correct any combination of t errors and e erasures in a given codeword, where t and e are jointly constrained by the inequality Specific values of t and e may be selected by a decoder when each C1 and C2 codeword is processed. The algorithm used to adaptively select the t and e values that apply when the C1 and C2 codes are jointly decoded is called the CIRC decoding strategy.","PeriodicalId":322309,"journal":{"name":"Joint International Symposium on Optical Memory and 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":"126009521","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}