Non-interferometric phase retrieval for collinear phase-modulated holographic data storage

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SPECIAL SECTION: REGULAR PAPER International Symposium on Imaging, Sensing, and Optical Memory (ISOM’ 19), Niigata, Japan

Non‑interferometric phase retrieval for collinear phase‑modulated holographic data storage Jianying Hao1 · Yuhong Ren1 · Yuanying Zhang1 · Kun Wang1 · Hui Li1,3 · Xiaodi Tan1,2 · Xiao Lin1 Received: 28 February 2020 / Accepted: 30 July 2020 © The Author(s) 2020

Abstract Because of its simple optical system setup and robust noise tolerance, non-interferometric phase retrieval is an important technique for phase-modulated holographic data storage. Usually, the iterative algorithm of non-interferometry needs hundreds of iteration numbers to retrieve phase accurately, the data transfer rate decreases severely. Strong constraints such as adding embedded data into the phase data page can reduce the iteration numbers, but this method decreases the code rate severely. In this paper, we proposed the advanced non-interferometric phase retrieval method based on the collinear system. By encoding the reference beam of the collinear optical holographic storage system with embedded data, the storage space of the signal beam data page is completely released and the encoding rate is doubled. The embedded data can provide more modulation index including phase and amplitude to shorten iterations, so the data transfer rate is also increased. In the simulation, we recorded a four-level phase pattern and retrieved the phase correctly. Keywords  Phase retrieval · Collinear holographic data storage · High code rate · Non-interferometry

1 Introduction With the development of the information age and the arrival of the big data era, the information storage demand has increased dramatically. The current storage technologies have been becoming unable to meet the human needs for data storage. In recent years, holographic optical storage technology has gradually become one of the most promising storage technology because of its high storage density, fast data transfer rate, and low cost and stable storage [1–4]. Optical holographic storage can encode and store data information in two ways: amplitude modulation and phase modulation. Because of its signal-to-noise ratio and

* Xiao Lin [email protected] 1



College of Photonic and Electronic Engineering, Fujian Normal University, Minhou District, Fuzhou 350117, China

2



Fujian Provincial Key Laboratory of Photonics Technology, Fuzhou 350117, China

3

Fujian Provincial Engineering Technology Research Center of Photoelectric Sensing Application, Fuzhou 350117, China



encoding rate are relatively low, the amplitude-modulated holography storage technology has been unable to meet the current explosive data storage requirements gradually [5, 6]. Phase-modulated holography storage technology has attracted more and more attention because of its higher signal–noise-radio and storage density compared with the amplitude-modulated method. Since phase information cannot be detected directly by detectors such as CMOS or CCD, people use interferometry or non-interferometry meth