Yuichi Kadokawa

Data Detection using Pattern Recognition for Multi-level Optical Recording

An optical disc system using multi-level (ML) amplitude-modulation can achieve higher data capacity and transfer rates than previous systems without changing the drive or pick-up head except to add a new chip set to the ML. The ML system can provide a bit error rate (BER) that is fully correctable around the order of 10-5 with sigma to dynamic range (SDR) < 2%. We improved the margin of SDR using a new data detection method that uses pattern recognition and evaluated its performance.

Multi-level optical recording using a blue laser

Combining Data Detection using Pattern Recognition (DDPR) with LSB (Least Significant Bit) Limited Modulation (LLM) effectively reduces data errors in a blue laser optical disc system. We confirmed that a recording capacity of 25 GB is feasible for a system by using a laser diode of 405-nm wavelength and a 0.65 numerical aperture objective lens was effective to reduce data errors in a blue laser optical disc system.

A New Data Modulation Method for Multi-Level Optical Recording

Previously, we developed a data detection method named data detection using pattern recognition (DDPR) for multi-level data recording on optical discs. We have added a new data modulation process, least significant bit (LSB) limited modulation (LLM), to DDPR in order to reduce data errors. The LLM modulates 11-bit input data into four eight-level data symbols (3 bits×4 data=12 bits). The experimental results showed that coupling LLM with DDPR was effective to reduce data errors.