  Implementing on-chip non-volatile optical memories has long been an actively
pursued goal, promising significant enhancements in the capability and energy
efficiency of photonic integrated circuits. Here, a novel optical memory has
been demonstrated exclusively using the semiconductor primary material,
silicon. By manipulating the optoelectronic effect of this device, we introduce
a hysteresis effect at the silicon-silicon oxide interface, which in turn
demonstrates multi-level, non-volatile optical data storage with robust
retention and endurance. This new silicon optical memory provides a
distinctively simple and accessible route to realize optical data storage in
standard silicon foundry processes.
