Toshiba Shows Off Blue Lasers

Toshiba will show a prototype laser diode for optical disc systems that are expected to hit the market around 2006.

The company will use the Ceatec exhibition, which begins next week just outside of Tokyo, to demonstrate a recently-developed blue-laser diode that is several times more powerful than current commercial models and has what Toshiba claims is the lowest noise figure of any such laser diode yet developed.

Red Hot Lasers

Lasers are used in optical disc systems to read and write information to the disc. The wavelength of the light produced by the laser is one of the main factors in determining the amount of data that can be stored on the disc. The shorter the wavelength, the smaller the light spot made on the disc surface--and so less space is required to store one bit of information and more can be stored on a disc.

Almost all current optical disc systems, including CD and DVD, make use of lasers that emit light in the red or infrared part of the spectrum. The CD system, which supports around 650MB of data storage, commonly uses a 780-nanometer wavelength laser, while the 4.7GB-capacity DVD system uses a laser with a wavelength of around 640 nanometers.

Getting the Blues

For next-generation systems manufacturers are working with lasers that emit blue or blue-violet light. Both the Sony-led Blu-ray system and Toshiba and NEC's proposed Advanced Optical Disc system use lasers with a wavelength around 405 nanometers and can realize storage capacities of between 23G bytes and 36G bytes per disc.

Toshiba's new laser has a similar wavelength so it won't help improve on data density but its high output power and low noise will enable reading and writing to take place at higher speed than the basic version of the systems. In current CD and DVD systems more powerful lasers have helped engineers do exactly the same thing and thus higher speed drives, such as 4X or 12X or 24X models, are available.

Toshiba expects faster versions of blue laser systems, the basic speed versions of which are still at the prototype stage or have only recently been launched, will be on the market around 2006, said Makoto Yasuda, a spokesman for Toshiba in Tokyo. The demonstration next week won't be of a optical disc system but rather a laser pointer using the new device, he added.

Ceatec 2003 takes place between October 7 and October 11 and Makuhari Messe in Chiba, Japan.