We present what is to our knowledge a new class of two-dimensional (2-D) modulation codes, called variable-length 2-D modulation codes, suitable for page-oriented optical data storage (PODS) systems that write and read data in a 2-D bit image format. These codes overcome the inherent spatial intersymbol interference in imaging PODS systems and improve the code rate performance of previous fixed-length 2-D modulation codes. The codes in this new class map one-dimensional input data blocks of variable lengths to 2-D output data blocks of variable lengths and are designed to limit error propagation. In this study we give several examples of fixed-length and variable-length 2-D modulation codes with various properties for imaging PODS systems. We also compare the bit-error-rate performance of these fixed-length and variable-length codes.
© 2003 Optical Society of America
(070.6020) Fourier optics and signal processing : Continuous optical signal processing
(200.3050) Optics in computing : Information processing
(210.0210) Optical data storage : Optical data storage
(210.4680) Optical data storage : Optical memories
Dhawat E. Pansatiankul and Alexander A. Sawchuk, "Variable-Length Two-Dimensional Modulation Coding for Imaging Page-Oriented Optical Data Storage Systems," Appl. Opt. 42, 5319-5333 (2003)