R&D: Optical Signal Amplification Between Pages for Holographic Storage

Japanese Journal of Applied Physics has published an article written by Kazuyoshi Yamazaki, Hitachi Ltd, Kokubunji-shi, Tokyo, Japan, and Masahiro Yamaguchi, Tokyo Institute of Technology School of Engineering, Meguro-ku, Tokyo, Japan

Abstract: “This work proposes a page differential intensity amplification for optical signal amplification in the intensity multiplexing holographic data storage system. The proposed method detects the signals of four cameras and reconstructs the intensity difference between two pages. The reconstructed intensity difference is amplified by the ratio of the readout beam amplitude to the local oscillator beam amplitude. Experiments showed that the proposed method can achieve a more stable signal amplification than the conventional amplification technique. Moreover, signal detection is possible with half the light intensity of the readout beam compared to the conventional direct detection method. This corresponds to 1.4 times the recording capacity increase if the capacity is limited by M/#, or the reduction to half the readout exposure time.“