Unequally spaced four levels phase encoding in holographic data storage

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• 作者：Ke Xu ; Yong Huang ; Xiao Lin ; Yabin Cheng ; Xiaotong Li ; Xiaodi Tan
• 关键词：Phase encoding ; Holographic storage ; Unequally spaced levels ; Decoding ; Correction
• 刊名：Optical Review
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：23
• 期：6
• 页码：1004-1009
• 全文大小：
• 刊物类别：Physics and Astronomy
• 刊物主题：Optics, Lasers, Photonics, Optical Devices; Atomic, Molecular, Optical and Plasma Physics; Quantum Optics; Microwaves, RF and Optical Engineering;
• 出版者：Springer Japan
• ISSN：1349-9432
• 卷排序：23

文摘

Holographic data storage system is a candidate for the information recording due to its large storage capacity and high transfer rate. We propose an unequally spaced four levels phase encoding in the holographic data storage system here. Compared with two levels or three levels phase encoding, four levels phase encoding effectively improves the code rate. While more phase levels can further improve code rate, it also puts higher demand for the camera to differentiate the resulting smaller grayscale difference. Unequally spaced quaternary level phases eliminates the ambiguity of pixels with same phase difference relative to reference light compared to equally spaced quaternary levels. Corresponding encoding pattern design with phase pairs as the data element and decoding method were developed. Our encoding improves the code rate up to 0.875, which is 1.75 times of the conventional amplitude method with an error rate of 0.13 % according to our simulation results.