Volume holographic data storage at areal density of 250 gigapixels/in.2

One thousand volume holographic data pages, each containing 1 X 10(6) pixels, are stored in a common volume of LiNbO3:Fe by use of the 90 degrees geometry. An effective transverse aperture of 1.6 mm x 1.6 mm, realized by repetition of this experiment at each of the eight surrounding locations, results in a demonstrated areal density of 394 pixels/mum(2) (254 Gpixels/in.(2)). Short-focal-length Fourier optics provide a tightly confined object beam at the crystal; the reference beam is angle multiplexed. Data pages retrieved with a 1024 x 1024 CCD camera are processed to remap bad spatial light modulator pixels and to compensate for global and local pixel misregistration and are then decoded with a strong 8-bits-from-12-pixels modulation code. The worst-case raw bit-error rate (BER) before error correction was 1.1 x 10(-3), sufficient to deliver a user BER of 10(-12) at an overall code rate of 0.61 user bits per detector pixel. This result corresponds to 1.08% of the well-known. theoretical volumetric density limit of 1/lambda (3). (C) 2001 Optical Society of America.