Kim K T, Cho B C, Kim E S, Gil S K
National Research Laboratory of Three-Dimensional Imaging and Display, School of Electronic Engineering, Kwangwoon University, 447-1 Wolge-Dong, Nowon-Gu, Seoul 139-701, Korea.
Appl Opt. 2000 Aug 10;39(23):4160-7. doi: 10.1364/ao.39.004160.
For analysis of effective phase-code multiplexing in a holographic memory system four types of phase code are generated and used as a reference beam. In computer simulations the size of the address beam is fixed at 32 x 32 pixels, and 0%, 5%, 10%, 15%, 20%, and 25% phase-error rates in a pixel are purposely added to the real phase values for consideration of the nonlinear phase-modulation characteristics of a practical spatial light modulator. Cross talk and signal-to-noise ratios (SNR's) are comparatively analyzed for these phase codes by calculation of the autocorrelation and the cross correlation. The pseudorandom code (PSR) has the lowest cross-correlation mean value of 0.067 among the four types of phase code, which means that the SNR of the PSR is higher than with other phase codes. Also, the standard deviation of the PSR, indicating the degree of recalled data degradation, has the lowest value, at 0.0113.
为了分析全息存储系统中有效的相位编码复用，生成了四种类型的相位编码并将其用作参考光束。在计算机模拟中，地址光束的大小固定为32×32像素，并且为了考虑实际空间光调制器的非线性相位调制特性，特意将像素中0%、5%、10%、15%、20%和25%的相位误差率添加到实际相位值中。通过计算自相关和互相关，对这些相位编码的串扰和信噪比（SNR）进行了比较分析。在四种类型的相位编码中，伪随机码（PSR）的互相关平均值最低，为0.067，这意味着PSR的SNR高于其他相位编码。此外，PSR的标准偏差（表示所恢复数据的退化程度）最低，为0.0113。
