Chapter 3 - Fundamentals of Optical Storage

Abstract

This chapter describes the basic operation of optical drives and discs and provides insight into what could drive the use of very large capacity optical disc technology. Optical discs serve a variety of uses in consumer and computer applications. They are the most widespread medium for physical content distribution and are used in computers for backup and archiving of content as well as file sharing. Optical disc drives use mirrors and lenses to move laser light around and focus it on the target optical disc for reading or writing. As the wavelength of the laser light decreases, the optical spots that are written or read become smaller and so higher density recording is possible. Thus blue laser optical discs can record more data than red laser optical discs. Data is written on optical discs as pits on predefined tracks. Optical data storage products are amazing for several reasons: a high degree of complexity reduced to ordinary assembly procedures; extremely low prices relative to performance and function; and a surprisingly high level of reliability. Optical discs can have a range of expected lifetimes depending upon the care and materials with which they have been made.