  We present the first demonstration of an integrated photonic phase-change
memory using GeSbTe-225 on silicon-on-insulator and demonstrate reliable
multilevel operation with a single programming pulse. We also compare our
results on silicon with previous demonstrations on silicon nitride. Crucially,
achieving this on silicon enables tighter integration of traditional
electronics with photonic memories in future, making phase-change photonic
memory a viable and integrable technology.
