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光盘信息符的横向尺寸决定了光存储系统的存储面密度。采用二维正方形光栅作为光盘模型,通过三维矢量衍射理论的数值仿真,计算了信息符横向尺寸对读出信号调制度的影响,确定了最佳调制度对应的最佳坑宽。并与标量衍射理论的定性分析进行了对比。根据标量衍射理论,最佳调制度应出现在信息符面积为读出光斑面积一半时对应的信息符尺寸附近,且小于该尺寸;信息符的最佳坑宽,即信息符特征宽度取决于所用的光学系统;矢量衍射理论的定量计算结果符合标量衍射理论的分析,并更接近实际情况;标量衍射理论概念简单,适于定性分析,定量计算则存在较大的误差。
The horizontal size of the disc information symbol determines the storage area density of the optical storage system. By using two-dimensional square grating as the optical disc model, the influence of lateral size of information symbol on the modulation degree of readout signal is calculated by numerical simulation of three-dimensional vector diffraction theory, and the best pit width corresponding to the best modulation degree is determined. And compared with the qualitative analysis of scalar diffraction theory. According to the scalar diffraction theory, the optimal modulation degree should appear around the size of the information symbol corresponding to half the area of the information spot and less than the size of the information symbol. The optimum pit width of the information symbol, ie, the width of the information character depends on the The quantitative calculation of vector diffraction theory is in accordance with the analysis of scalar diffraction theory and is closer to the actual situation. The concept of scalar diffraction theory is simple, suitable for qualitative analysis, and there is a big error in quantitative calculation.