Modulation codes for multi-level photochromic optical storage

摘要

Multi-level optical storage is a promising approach to increase recording density and data transfer rate significantly without altering optical and mechanical parameters of current optical disc systems. Multi-level amplitude modulation and multi-level run-length limited modulation are two different important recording approaches. In this paper, we discuss and compare these two multi-level modulation principles and corresponding multi-level coding schemes. With advanced coding and signal detection, multi-level run-length limited modulation shows better performances in terms of higher recording density. We present a new 8-ary (1,3) RLL code constructed by state splitting algorithm for photochromic storage channel. The proposed code has only two coding states and high coding density of 3.0 bits per minimum mark. The encoder/decoder is simple and easy for implementation, which can be applied in future high density multi-level optical storage systems.