Abstract

PHB memory has been a good candidate for a future ultra high density memory for these ten years. This PHB memory is considered to realize the recording density of 1000 times higher than conventional optical memories because it can store wavelength-multiplicitically 1000 bits in a 1-μm diameter recording spot. But not so many researchers are working on PHB memory compared to the number of researchers wrestling with realization of higher recording density of other types of memory such as magnetic or optical ones. One of the reasons is based on the doubt whether high speed readout is possible in such a high density recording in 1-μm diameter spot. Therefore one of the most important research on PHB memory is the estimation of degree of coexistence between high recording density and high speed readout.

© 1991 Optical Society of America