Two-Dimensional Constant-Weight Block Code in Orthogonal Aperture-Multiplexing for Multilayered Waveguide Holographic Memory

For a two-dimensional constant-weight block code, we show that the recording density is proportional to code rate and the second power of the size of the bright point. Second, we show four constant-weight block codes (two 2:16 codes, a 4:24 code, and a 4:16 code) with different code rates. In simulation experiments, we measured the maximum size of bright points for each code, the bit error rate was practical (10(-4) or less), and simulation results show that the maximum size increases as the code rate decreases. Then, we show that the highest recording density is achieved with the two 2:16 codes and the 4:24 code and that these codes are suitable for orthogonal aperture-multiplexing. We also show that there is a trade-off between multiplexity and the code rate. [DOI: 10.1143/JJAP.47.8440]