  Silicon photonics arises as a viable solution to address the stringent
resource demands of emergent technologies, such as neural networks. Within this
framework, photonic memories are fundamental building blocks of photonic
integrated circuits that have not yet found a standardized solution due to
several trade-off among different metrics such as energy consumption, speed,
footprint, or fabrication complexity, to name a few. In particular, a photonic
memory exhibiting ultra-high endurance performance (> 10^6 cycles) has been
elusive to date. Here, we report an ultra-high endurance silicon photonic
memory using vanadium dioxide (VO_2) exhibiting a record cyclability of up to
10^7 cycles without degradation. Moreover, our memory features an ultra-compact
footprint below 5 {\mu}m with potential for nanosecond and picojoule
programming performance. Our silicon photonic memory could find application in
emerging photonic applications demanding high number of memory updates such as
photonic neural networks with in-situ training.
