Coherent scattering noise reduction method with wavelength diversity detection for holographic data storage system

• Published in: Japanese Journal of Applied Physics Vol. 56; no. 9S; pp. 9 - 20
• Main Authors: Nakamura, Yusuke, Hoshizawa, Taku, Takashima, Yuzuru
• Format: Journal Article
• Language: English
• Published: Tokyo The Japan Society of Applied Physics 01.09.2017; Japanese Journal of Applied Physics
• Subjects: Coherent scattering; Data storage; Mathematical analysis; Molecular chains; Noise reduction; Quality; Signal quality; System effectiveness
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/JJAP.56.09NA08

A new method, wavelength diversity detection (WDD), for improving signal quality is proposed and its effectiveness is numerically confirmed. We consider that WDD is especially effective for high-capacity systems having low hologram diffraction efficiencies. In such systems, the signal quality is primarily limited by coherent scattering noise; thus, effective improvement of the signal quality under a scattering-limited system is of great interest. WDD utilizes a new degree of freedom, the spectrum width, and scattering by molecules to improve the signal quality of the system. We found that WDD improves the quality by counterbalancing the degradation of the quality due to Bragg mismatch. With WDD, a higher-scattering-coefficient medium can improve the quality. The result provides an interesting insight into the requirements for material characteristics, especially for a large-M/# material. In general, a larger-M/# material contains more molecules; thus, the system is subject to more scattering, which actually improves the quality with WDD. We propose a pathway for a future holographic data storage system (HDSS) using WDD, which can record a larger amount of data than a conventional HDSS.