This paper reviews the analyses and the experimental results of Micro-reflector optical disc system. In Micro-reflector
optical disc, data are recorded on multiple virtual planes in a monolithic holographic medium. We have demonstrated
the possibility of huge capacity from our analyses of readout characteristics of the Micro-reflector. In addition, we have
developed the five-axis servo control system in order to achieve precise control of two counter-propagating light spots in
recording media. Using this system, we succeeded in four-layer recording/readout.