Tokyo Work on holographic information storage system technology will reach a milestone this week when a technical committee of Ecma International holds its first meeting here to begin a standardization effort.
The TC44 committee will use the single-beam technology developed by Hideyoshi Horimai and Yoshio Aoki at their company, Optware Corp., as the basis of its standards for holographic disks and cards.
The technologists, both former optical-disk-storage developers at Sony, believe single-beam holographic disks will be the high-density information storage successor to the Blu-ray and high-definition-DVD optical disks now coming to market for consumer electronics. But they know that their fight to make Optware's technology a success is just beginning.
"Holographic recording has been known for over 40 years," said Horimai, founder and CTO of Optware, "but it's never been commercially available." Optware's road map shows holographic storage systems with capacities growing from 100 Gbytes to several terabytes. The company's first disks will target archival storage for businesses and professionals and will be released sometime this year. Drives for consumer systems will be released after 2006.
The Blu-ray Disc Association says its dual-layer disks can store 50 Gbytes, or more than 4.5 hours, of high-definition audio and video content. By increasing the number of recording layers, the association says its disks will be capable in the future of storing 100 to 200 Gbytes. The DVD Forum said the dual-layer HD-DVD-ROM disks for which it is setting specifications can store eight hours of high-quality content.
Horimai said Optware's technology is groundbreaking on several fronts. While other holographic-recording systems require separate signal and reference beams, making the systems bulky, Optware said the beams are coaxially arranged by its technology to create what it calls a collinear system. The system's disk has prerecorded address pits and will use a servo system similar to present CD-DVD disk systems.
Optware expects storage requirements will grow, especially for archiving applications, but not without the support of a single standard and multiple partners, said president and CEO Aoki. That's why Optware and five other companies proposed that Ecma form the holographic information storage technical committee, which will hold its first meeting March 3 and 4. Ecma, which began life in 1961 as the European Computer Manufacturers Association, said the TC44 committee will work on standards for 200-Gbyte holographic versatile disk (HVD) cartridges, 100-Gbyte HVD read-only disks, 30-Gbyte HVD cards and an optional provision for HVD-ROM disks.
"We are particularly gratified that Ecma has chosen to start its standardization work with projects that make use of our collinear technologies for holographic versatile disks and holographic versatile cards," Aoki said.
Ecma expects to submit the standards to the International Organization for Standardization (ISO) in December 2006.
Optware's partners in the holographic standards proposal are CMC Magnetics, Fuji Photo Film, Nippon Paint, Pulstec Industrial and Toagosei. The companies attended a preliminary meeting of TC44 last December, along with such major consumer electronics manufacturers as Hitachi, Matsushita, Philips, Pioneer, Sony and Toshiba. InPhase Technologies (Longmont, Colo.), a four-year-old company developing another holographic recording system based on research originally conducted at Bell Labs, also attended.
Optware and its partners have announced plans to launch the HVD Alliance next week, timed to coincide with the Ecma meeting. "We learned when we were developing magneto-optical disk systems at Sony that if a limited number of companies are involved, the technology does not make enough progress and the capacity does not grow fast enough. If the [TC44] standardization activities attract the attention of more companies and organizations, larger-capacity disks may become available from those companies," Aoki said.
Horimai said that optical disk system makers have been increasing the disks' capacity by squeezing the beam used to read and write data, but he added that that approach is reaching its limits. Collinear holography recording is different and can support higher data rates and capacities while maintaining the advantage of random access, he said.
"Conventional optical-disk systems record data bit by bit. One laser beam pulse records only one bit. It is really wasteful. Our system records 60,000 bits with one pulse. And it makes use of almost the whole disk substrate as recording media. Thus the disk has no 'recording layer' like conventional CD-DVD disks," Horimai said.
Shifting the cone
With collinear technology, one pulse can record one page of 60,000-bit data on a disk substrate in an inverted, truncated cone shape that has a 200-micron diameter at the bottom and a 500-micron diameter at the top. Another page of data is recorded by slightly shifting the center of the cone shape at a certain interval.
In an experiment, Optware verified that a minimum 3-micron interval can realize a capacity of 3.9 terabytes for one disk. A 12-centimeter disk will have a 100-Gbyte capacity when the shapes are multiplexed with an 18-micron interval. The capacity doubles when the interval is decreased to 13 microns and increases to 500 Gbytes when the interval is shortened to 8 microns, according to Optware.
Optware has demonstrated the recording and playback of video footage by spinning a 120-mm disk at 100 revolutions per minute. It said that 12,000 pages can be recorded on one track of the disk.
Optware said its initial HVD system will be a 200-Gbyte device for business customers.
"Once that system proves its performance, it should usher in consumer applications," Aoki said. "Optware wants to focus on the consumer market" with its second-generation products, he said, adding that those systems are expected to hit the market around 2010.
"For consumer applications, it is more important to involve major consumer electronics manufacturers than to establish ISO standards," said Aoki. Optware's technology has already drawn industry attention, with Sony having placed an order last July for the collinear holography storage system. Optware's investors include Intel 1 Capital, Matsushita and Fuji Photo Film.
For compact consumer systems, there are still hurdles to clear. One involves the holographic light source. At present, Optware uses solid-state green lasers with an output for writing of about 1 watt. No semiconductor laser with such a high output is available at present, but for consumer systems, a compact semiconductor laser is essential.
"If the sensitivity of the photopolymer is improved, a much lower-power laser can be used," said Aoki.