The write strategy investigation of multi-level optical storage in azobenzene liquid crystal polymer film

With the increasing demand of optical storage capacity, multi-level (ML) optical storage based on multi-level-amplitude modulation is receiving more and more attention, for it transmits more information ove a fixed bandwidth channel by using the available SNR more efficiently. We proposed an ML optical storage technology in azo LCP film based on polarization angle division. In this paper, the write strategy is developed by a ML write-compensation system that corrects for non-linearities of the data signal. The dynamic transmittance range is extended with the full monotonic range of angle and the varaition of each amplitude level relative to our dynamic range is improved. The experiments of imroved linear and nonlinear 16-level storage in azo LCP are demonstrated. The effects of thickness non-uniformity on linear and nonlinear 16-level storage are discussed.