All-photon non-volatile multi-level optical switch based on phase change material

Multi-level optical switches play an important role in all-photon communication networks. In this paper, we demonstrate an all-photonic non-volatile, quasi-continuous, multi-level optical switch which based on phase change material (PCM, Ge2Sb2Te5) and fiber micro-structure. With the help of 793nm CW laser and 532nm nanosecond pulse laser, this all-photon multistage optical switch can be operated repeatedly in six switching states. In multi-stage modulation, writing is realized by a 532 nm nanosecond pulsed laser with pulse energy of 1.426 mJ, and erasing is realized by a 793 nm CW laser with pulse powers from 4.2 to 9.6 mW. The experiment shows the optical switch has the advantages of high optical contrast (about 38%), repeatability and non-volatile (0.2dB). Hopefully, the all-photonic optical switch presented in this paper provides insights on optical computing and lays some experimental basis for all-photon information transmission.