Electrical Pulse Driven Multi-Level Nonvolatile Photonic Memories Using Broadband Transparent Phase Change Materials

Here we demonstrate a multi-state electrically programmed low-loss nonvolatile photonic memory based on a broadband transparent phase change material (Ge2Sb2Se5, GSSe) with ultra-low absorption in the amorphous state. A zero-static-power, and electrically driven high-state photonic memory was realized on a silicon-on-insulator platform, featuring amplitude modulation up to 0.2 dB/{\mu}m and an ultra-low insertion loss of 0.0015 dB/{\mu}m, with a newly designed paired micro-heaters along the both sides of waveguide without horizontal contact. The step size (absorption per state) and total resolution of PRAM is cascaded with the length of GSSe material and the number of paired heaters to tune the number of individual memory islands. We also proposed a partial amorphization scheme with single pair of unsymmetric heaters to realize 6 states response to enhance energy and footprint efficiency of PCM devices. A cyclability test was performed over the proposed PRAM reaching half-million set-reset cycles with stable bi-state optical responses.