Laser Coupler

Nichia, Sony develop laser coupler for optical disks

Japan-based electronic companies Nichia Corp. and Sony Corp. unveiled the latest piece of their strategy to capture the optical disk market, developing a dual wavelength laser coupler that integrates red and blue-violet lasers together with a corresponding photo detector and lens and prism.

The coupler is a single integrated device with a 660nm red laser for DVD playback and 405nm blue-violet laser for optical disk playback. The companies expect that combining both functions in a single device will simplify the design of optical disk systems, allowing smaller and more reliable Blu-ray Disc (BD) players as well as HD-DVD players.

The prototype coupler measures 7.2(H)-by-13.5(W)-by-6.7()mm. However, because existing couplers measure 6.5mm deep for CD/DVD drives and 5mm deep for 0.5-inch high slim-type drives, the companies expect to further shrink the coupler before it enters volume production in late 2005.

In addition, the prototype lacks an integrated infrared laser for CD disk. A Sony spokesperson said the company is now producing red/infrared dual wavelength lasers for PlayStation 2 and other products, but is undecided whether it would integrate a third laser into the coupler.

Both Nichia and Sony have been co-developing a blue-violet laser diode for optical disc recording and playback since June 2002. In April 2004, the companies inked a cross-licensing agreement allowing sharing of hundreds of patents both companies own related to blue-violet laser diode technology.

The agreement also called for the companies to develop a line of laser devices including diodes and couplers, thus enabling Nichia to enter the laser coupler market for the first time.

Nichia is in the forefront of Japanese companies racing to develop blue-violet lasers for optical disks, being the first to sample 405nm laser diodes and expected to begin volume production next spring. Competitors include NEC, Sanyo, Toshiba and Sharp.

In May, Sony unveiled an optical pickup head for Blu-ray Disc systems, to begin sampling next month.

- Yoshiko Hara and Spencer Chin

EE Times