Holographic data storage at 2+ Tbit/in~2

摘要

The onslaught of big data continues even as growth in data storage density tapers off. Meanwhile, the physics of holography continues to suggest the possibility of digital data storage at densities far exceeding those of today's technologies. We report on recent results achieved with a demonstrator platform incorporating several new second-generation techniques for increasing holographic data storage (HDS) recording density and speed. We present data showing the recovery of HDS data at a density of 2 Tbit/in~2. Since the highest reported areal densities for hard disk drive products currently hover in the 1 Tbit/in~2 range, we have adopted 2 Tbit/in~2 as a milestone likely to generate interest in the technology. The demonstrator is based on an advanced pre-production prototype, and so inherits highly functional electronic, mechanical, and optical subsystems. It employs a high-NA monocular architecture with proven angle-polytopic multiplexing. The demonstrator design includes several second-generation innovations. The first, dynamic aperture multiplexing, greatly increases the number of multiplexed holograms. The second, the DRED? medium formulation, provides dramatically higher dynamic range to record these holograms. These two features alone theoretically allow the demonstrator to exceed 2 Tbit/in~2. Additionally, it is equipped with the capability of quadrature homodyne detection, permitting phase quadrature multiplexing (QPSK modulation), and the potential to further increase user capacity by a factor of four or more. The demonstrator has thus been designed to achieve densities supporting the multi-terabyte storage capacities required for competitive products, and to demonstrate the potential for Moore's-Law growth for years to come.