Holographic Firm Claims Data Storage Density Record

The first-generation holographic drive, to be delivered later this year, has a capacity of 300 gigabytes on a single disk, with a 20 megabyte per second transfer rate.
LONDON — InPhase Technologies Inc., a five-year old startup company trying to bring holographic data storage technology to market, has claimed to have recorded the highest data density of any commercial technology by recording 515 gigabits of data per square inch using its Tapestry system.

Long foreseen as the likely successor to magnetic and optical storage holographic storage takes advantage of volumetric efficiencies rather than only recording on the surface of a material. InPhase (Longmont, Colo.) said it is on track to deliver the industry’s first holographic drive and media later this year.

The first generation holographic drive has a capacity of 300 gigabytes on a single disk with a 20 megabyte per second transfer rate. The first product will be followed by a family ranging from 800-Gbytes to 1.6-Tbyte capacity. Holographic information density depends on the number of pixels/bits in a page of data; the number of pages that are stored in a particular volumetric location; the dynamic range of the recording material; the thickness of the material, and the wavelength of the recording laser.

In InPhase’s latest demonstration there were over 1.3 million bits per data page, and 320 data pages spaced 0.067 degrees apart were stored in the same volume of material. A collection of data pages is referred to as a book, and InPhase’s polytopic recording architecture enables more holograms to be stored in the same volume of material by overlapping not only pages, but also books, the company said. Three tracks of overlapping books were written with a track pitch of 700 microns into InPhase Tapestry material that was 1.5 millimeters thick. A 407-nm wavelength laser was used to write the data, the company said.

“The latest results from our ongoing tests on holographic data density have surpassed expectations,” said Kevin Curtis, chief technology officer of InPhase, in a statement. “We are particularly pleased at the rate of improvement. In April of 2005, we demonstrated 200-Gbits per square inch data density and, a year later, the density has increased more than 2.5 times,” he added.

At these densities one Tapestry disk could hold the equivalent of 106 DVD movies. For IT managers dealing with archiving millions of email messages, higher densities mean savings on space, time, and power.

The write transfer rate is determined by the time required to position the laser at the correct angular address, the speed of the shutter, the laser power, and the exposure time. In this demonstration the average exposure time per page was 2.7 milliseconds, which translates into a write transfer rate of 23 megabytes per second, the company stated.

InPhase was admitted to EE Times’ “Silicon60” list of emerging technology companies in November 2005.

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