Single-mode fiber multi-level all-optical switching using GSST-graphene oxide hybrid thin film structure

Ge2Sb2Se4Te1 (GSST) exhibits unprecedented broadband transparency over the infrared wavelength range and has emerged as a promising functional material in photonic applications that operate in the optical fiber telecommunication wavelength band. In this work, GSST and graphene oxide (GO) are integrated into an optical fiber link to achieve all-fiber non-volatile multilevel photonic memory. The GSST and GO (GSST-GO) duo-layer hybrid structure is sandwiched between two optical fiber ferrules, where the GO acts as a localized heat source to initiate the phase transition of GSST upon optical excitation. The GSST-GO-coated fiber exhibits a low insertion loss of 0.8 dB and a maximum readout contrast of about 32%, with at least five distinguished memory states. The response time of the device is measured in the range between 2.5 and 9.5 μs. This work serves as a proof of concept on implementing the GSST-GO duo-layer hybrid structure in optical fiber platform to realize all-fiber non-volatile multi-bit channel control or data storage.