Kazuyoshi Adachi

High-Speed Write/Read Techniques for Blu-ray Write-Once Discs

We have been developing high-speed write/read techniques for Blu-ray discs. We carried out 1–12× write/read tests on a phase-change Blu-ray write-once disc using an improved tester, an adaptive partial-response maximum-likelihood (PRML) technique, and a new write adjustment method. Sufficiently good limit equalizer jitter values of less than 6.5% were obtained under all write-speed conditions. Good bit error rates of less than 10-6 and fair power margins of more than ±10% were obtained under all write/read speed conditions.

Crosstalk Cancellation for 50-GB/Layer Optical Recording

We have developed write/read technologies for post-Blu-ray Disc (BD) with a capacity of 50 GB/layer. In this report, the authors propose a crosstalk cancellation method that minimizes the error between the crosstalk canceled signal and the target signal that is generated from the binary output of an adaptive-partial response maximum likelihood (PRML) decoder. The experimental results obtained using our method show that the bit error rate is reduced to 1/100. A high-density recoding of 50 GB/layer was demonstrated using our method.

Read/Write Technology for 50 GB/layer at 100 Mbps

We developed read/write technology for high-density optical data storage of 50 GB/layer at a data transfer rate of 108 Mbps. We demonstrated the writing and reading capabilities of a 50 GB/layer optical disk recording system at 36 Mbps with a sufficient power margin, using a three-beam crosstalk canceller with optical response equalizers, using a phase-change write-once disk. Bit error rates were below 1×10-4 at 108 Mbps. Experimental results showed that the technology realizes writing and reading densities two times higher and data transfer rates three times higher than those of Blu-ray with a simple optical component such as Blu-ray.

Manufacture of 27 GB Read-Only-Memory Disc Using Deep-UV Beam Recorder with Two-Dimensional Optical Compensation

A novel mastering method using a deep-UV laser beam recorder (LBR) with two-dimensional optical compensation has been proposed. Using this technique, uniform fine pits can be created. The result reveals that a 27 GB read-only-memory (ROM) disc can be realized. The bottom jitter with a limit equalizer was 7.5%.