M-ary optical data storage for CD, DVD and beyond

In this paper, we introduce the theoretical and practical concepts behind M-ary signaling on optical recording systems such as compact disc (CD), digital versatile disc (DVD) and evolving next generation formats based on blue lasers. We show that there is sufficient signal-to-noise ratio on all recording formats (ROM, R and R/W) and give examples of how density and data transfer rate can be improved by two to three times with no changes in disc media or recorder.