Two competing technologies which enable more than 20GB of data to be stored on each side of an optical disc are nearing commercialisation, leading to fears that the industry could be split between support for one format or the other.

Toshiba and NEC have proposed their AOD (Advanced Optical Disc) technology as a standard to the DVD Forum, a consortium of 212 companies. The forum is expected to settle on full specifications for AOD by the second quarter next year, said Hideyuki Irie, a DVD Forum official.

Earlier this year, the basic specifications for an alternative high-capacity standard known as Blu-Ray were announced by nine companies: Matsushita, Philips, Sony, Hitachi, LG, Pioneer, Samsung, Sharp and Thomson.

The AOD is based on a 405-nanometer-wavelength blue laser and can store up to 20GB of data on one side of a disc of the same size as a conventional DVD. AOD drives are expected to be commercially produced next year according to NEC spokesman Mitsumasa Fukumoto.

Blu-Ray, which also uses a 405-nanometer blue laser, can store up to 27GB of data on one side or 50GB on two sides, is expected to be commercialised soon, but no launch date has been set yet said Sony's Tsuyoshi Sakaguchi.

The industry is concerned about a battle between the AOD and Blu-Ray standards in future, according to Irie.

"The forum has been trying to merge the two formats into one standard and hasn't given up on doing so, but technically speaking, it is very difficult unless each side compromises," Irie said.

However, the forum sees little possibility of those concessions being made, Irie said.