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Holographic storage has been pursued since Polaroid scientist Pieter J. Van Heerden first thought of storing data in three dimensions in 1963, but InPhase Technologies says it is close to making the technology a commercial reality.
The company, which has netted $61 million in funding since being spun out of Lucent Technologies' storied Bell Labs nearly five years ago, has been working on holographic storage since 1994. It expects to begin shipping holographic storage products late next year.
By using all of the media instead of just the surface, holographic storage promises breakthroughs in storage density and cost and data transfer rates. It differs from spinning disk technology in that the media and head are fixed and the disk rotates very slowly; the company doesn't even track RPMs. Those differences also make holographic storage more reliable.
The initial product, a 130mm disk, is expected to hold 300 gigabytes (GB) of data the equivalent of 462 CDs with a transfer rate of 20 megabytes (MB) per second. InPhase says capacities for its "Tapestry" family of drives will reach 1.6 terabytes (TB) on a single disk by 2010.
"It's a real breakthrough from an optical perspective," says InPhase marketing vice president Liz Murphy. "No one has even come close."
Even holographic storage competitors like Optware are using InPhase's media, Murphy says. "We're selling media to almost everyone doing holographic research," she says.
Better components are still needed to make commercial deployment a reality, but Murphy says InPhase expects those pieces to fall into place over the next year or so.
With a 50-year media lifespan and a cost that is expected to become "significantly cheaper" than LTO tape over time, InPhase anticipates that industries with major archiving needs will be natural adopters of holographic storage. Those markets include professional video, regulatory compliance, medical imaging, satellite imaging and scientific applications.
The451 Group analyst Sonia Lelii said in a recent report that InPhase is close to solving the decades-old storage riddle, but still faces some hurdles.
InPhase "must persuade the broader market that it's a commercially viable product," said Lelii. "Some key elements are still lacking ... [T]he speed and capacity levels need to mature before the technology can compete with current magnetic and optical formats. Don't expect holographic storage to be used in data centers until it has been vigorously tested and proven over time, but there's little doubt that momentum is building."
The prototype drive records data into InPhase's two-chemistry Tapestry photopolymer WORM (write once, read many) material. The recording material is 1.5mm thick and is sandwiched between two 130mm diameter transmissive plastic disk substrates. Hitachi Maxell, Ltd., a key investor and development partner of InPhase, designed and developed a new cartridge for the light-sensitive recording material. Maxell is also developing high-volume media manufacturing processes.
The prototype arranges more than one million bits of data into a single page, which is recorded with a single flash of a 407nm laser beam. Multiple pages of data, referred to as a book, are recorded in one spot on the disk, providing about 12MB of data in a single book location.
The prototype drive includes all drive subsystems such as the auto load/unload mechanics, servo system, holographic read/write head, data channel and electronics. The media cartridge is loaded and unloaded automatically using a mechanism designed and developed for InPhase by ALPS Electric Co., an InPhase investor and development partner. The servo system, designed and developed by InPhase, regulates both radial and rotational movement of the media and the angle of the reference beam.
The holographic read/write head is the heart of the system; the 407nm blue lasers recently available in other optical devices provide the wavelength required for high-capacity holographic storage. CCDs and spatial light modulators used in digital cameras were also an important enabler.