多阶光存储原理分析及其读写系统前端信号处理研究

运用矢量衍射理论的计算方法(耦合波方法，时域有限差分法)，对两种多阶光存储方案(坑深调制，坑形调制)进行了原理性分析，并简略分析了利用相变材料的幅值调制实现多阶存储的原理.由此得出多阶光存储技术的实现是利用了光与物质之间的相互作用，使光对记录介质产生作用，同时介质也对光的某些特性进行调制，而这些特征的改变一般都不止两个状态0或1，用数字方式将这多个状态记录下来便实现了多阶数字存储.此外,还提出了多阶光盘前端信号处理系统的设计与开发.该系统是多阶光存储实验系统的重要组成部分，可输出RF,TE,FE等伺服与误差信号，并将信号反馈给多阶处理芯片；同时系统还可对光学头的激光读写功率及写入时间进行控制，并能使其实现自动调焦和道跟踪.关键词：多阶光存储矢量衍射理论时域有限差分法

Analysis on the principle of multilevel optical data recording and the study on the processing of the front signals of a multilevel read-write system

This paper utilized the calculation methods in vector diffraction theory, such as the wave_coupled method and the finite difference time domain method, to a nalyze two multilevel optical recording methods in principle. Meanwhile the prin ciple to achieve multilevel optical recording by modulating the amplitude of pha se_change media is also discussed. According to these analysis, the multilevel d ata recording utilizes the mutual action between laser and recording media. Lase r beam has some special effects on the media; simultaneously the media will modu late some characteristics of the light. Generally, the diversities of these cha racteristics are more than two states, so the multilevel data recording can be a chieved by recording these different states. Besides, the design and development of the front signals processing system is also presented. It is an important pa rt of the experimental system for multilevel recording. It can output some servo and error signals such as TE, FE and RF etc, which will be fed back to the appr opriative chip for multilevel recording. Additionally the processing system not only can control the laser power and the writing time of the optical pickup, but it also can make the pickup realize focusing and tracking automatically.