Abstract

Conventional optical recording systems like the compact disc (CD) and digital versatile disc (DVD) use binary sig-naling in conjunction with runlength limited codes. This modulation is essentially pulse width modulation (PWM) where information is conveyed in the length of the marks on the disc and the spacing between them. Various papers addressing fixed-length multilevel marks have appeared using M 8 12 levels [1–4]. The first multilevel CD-R and CD-RW compatible system achieves 2.5 bits/0.6µm data cell. Write-once and re-writable optical discs are highly nonlinear and precompensation is used to linearize the channel so conventional coding and signal processing for a linear bandlimited channel can be employed [3].

© 2003 Optical Society of America