Cavity-enhanced eigenmode and angular hybrid multiplexing in holographic data storage systems.

Bo E. Miller,Yuzuru Takashima

doi:10.1364/oe.24.029465

Bo E. Miller, Yuzuru Takashima

Open Access

https://doi.org/10.1364/oe.24.029465

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Abstract

Resonant optical cavities have been demonstrated to improve energy efficiencies in Holographic Data Storage Systems (HDSS). The orthogonal reference beams supported as cavity eigenmodes can provide another multiplexing degree of freedom to push storage densities toward the limit of 3D optical data storage. While keeping the increased energy efficiency of a cavity enhanced reference arm, image bearing holograms are multiplexed by orthogonal phase code multiplexing via Hermite-Gaussian eigenmodes in a Fe:LiNbO3 medium with a 532 nm laser at two Bragg angles. We experimentally confirmed write rates are enhanced by an average factor of 1.1, and page crosstalk is about 2.5%. This hybrid multiplexing opens up a pathway to increase storage density while minimizing modification of current angular multiplexing HDSS.

Highlights

As internet bandwidth continues to increase, consumers and corporate segments alike are moving their ever expanding data to remote data centers
In this paper we report the experimental demonstration of a cavity enhanced, orthogonal mode-angular hybrid multiplexing, which enables Holographic Data Storage Systems (HDSS) to accesses more multiplexing DOFs
The 0.6° angular separation was chosen by monitoring the diffraction efficiency of a hologram written with a Gaussian reference beam: since Bragg side lobes are expected to be ~1x10−4 of the Bragg matched efficiency [9], we chose the separation by rotating the hologram to 1x10−2 of the Bragg matched efficiency, at 0.4°, and proceeded to the increment on the goniometer stage, 0.6°

Summary

Introduction

As internet bandwidth continues to increase, consumers and corporate segments alike are moving their ever expanding data to remote data centers. HDSS, on the other hand, offers maximum data transfer rates of 2.4 Gbps and a storage density of 720 GB/in while maintaining the same ~50 year archive life as AD at one 13th of the total cost of ownership of an AD system [3]. With all of these advantages, HDSS is a promising option of WORM memory in cold data storage.

Crosstalk of single holograms read out by orthogonal cavity eigenmodes

Combined angular and mode multiplexing with cavity enhanced writing

Findings

Discussion

Conclusions