Daiichi KOIDE^*, Takeshi KAJIYAMA, Ryuji SATO, Haruki TOKUMARU, and Yoshimichi TAKANO

Science and Technology Research Laboratories, NHK (Japan Broadcasting Corporation), Setagaya, Tokyo 157-8510, Japan

(Received January 9, 2014; Accepted March 31, 2014)

We report on the recording characteristics of a near-field optical recording thin optical disk (NFR-TOD). We proposed a new cooling-less-type write strategy for recording, applied it to the NFR-TOD experimental system, and also applied a partial response maximum likelihood (PRML) signal processing, which was evaluated and optimized the PR coefficient for playback signals of the prototype NFR-TOD. The NFR-TOD has a track pitch of 160 nm and improved recording characteristics. The experimental results of the prototype NFR-TOD and the system indicate sufficiently low bit error rates (bERs) for recorded data at a fourfold higher recording density than the current Blu-ray disk.

Key words: near-field optical recording, thin optical disk, solid immersion lens, high density, partial response maximum likelihood

^*E-mail address: koide.d-jy@nhk.or.jp