Multiplexed Optical Data Storage

The paper presents an overview of techniques designed to increase data storage density by putting more than a single bit of information into a single pit. The current solution differs from previous suggestions in that we do not require an improved signal-to-noise ratio to achieve higher data storage density. Instead we use a hitherto unutilised feature of light: its polarisation. Although the research is still very much ongoing the paper reports on the progress so far and summarises future development directions