Drive Architectures

We propose a new servo technique for controlling the reference beam angle in angular multiplexing holographic memory to attain higher capacity and higher speed data archiving. An orthogonally polarized beam with an incident angle slightly different from that of the reference beam is newly applied to the optics. The control signal for the servo is generated as the difference between the diffracted light intensities of these two beams from a hologram. The incident angle difference between the beams to the medium was optimized as sufficient properties of the control signal were obtained. The high accuracy of the control signal with an angle error lower than 1.5 mdeg was successfully confirmed in the simulations and experiments.

“…Other optical conditions were based on our experimental system, as summarized in Table I. The intensities of signal A, signal B, 37,38) and the control signal were calculated from…”

Section: Optimization Of Split Angle Between Reference Beam and Servo...mentioning

confidence: 99%

Highly accurate servo control of reference beam angle in holographic memory with polarized servo beam

Hosaka¹,

Ogata²,

Yamada³

et al. 2016

“…The dynamic range M# in Table I is standard considering the performance of the existing photopolymer. 24) The data pages are composed of 32 Â 32 data symbols, and each symbol takes one value out of the 38-level SQAM that consists of the multi level intensity and phase modulations, as shown in Fig. 6.…”

Section: Simulation For Evaluating Reconstruction Characteristics In ...mentioning

confidence: 99%

Double-Referential Holography and Spatial Quadrature Amplitude Modulation

Zukeran

Okamoto

Takabayashi

et al. 2013

We proposed a double-referential holography (DRH) that allows phase-detection without external additional beams. In the DRH, phantom beams, prepared in the same optical path as signal beams and preliminary multiplexed in a recording medium along with the signal, are used to produce interference fringes on an imager for converting a phase into an intensity distribution. The DRH enables stable and high-accuracy phase detection independent of the fluctuations and vibrations of the optical system owing to medium shift and temperature variation. Besides, the collinear arrangement of the signal and phantom beams leads to the compactness of the optical data storage system. We conducted an experiment using binary phase modulation signals for verifying the DRH operation. In addition, 38-level spatial quadrature amplitude modulation signals were successfully reproduced with the DRH by numerical simulation. Furthermore, we verified that the distributed phase-shifting method moderates the dynamic range consumption for the exposure of phantom beams.

“…Optical memory systems are known as a perspective candidate to be used for large volume data archivation. [1][2][3] Longevity of holographic material, resistance of holographic images to surface local damages and scratches, immunity of holographic carrier to outer electro-magnetic influence, and high-speed read-out capability are among the main advantages of holographic methods application for data storage issue. Many reports were published in the last several decades in the field of holographic memory development.…”

Section: Introductionmentioning

confidence: 99%

Optical memory system based on incoherent recorder and coherent reader of multiplexed computer generated one-dimensional Fourier transform holograms

Одиноков

Zlokazov

Donchenko

et al. 2017

The present article highlights the development results of archive memory holographic system based on application of computer generated Fourier holograms. The proposed idea allows realization of holographic principles of digital data record using simple and compact optical devices. Special interest is paid to synthesis and multiplexed record of one-dimensional Fourier transform holograms. The principal schemes of constructed prototypes of incoherent data recorder and coherent data reader are described in the present paper. The results of experimental implementation of the constructed devices are presented.