Large Thermo-Optic Blue Shift in a Silicon Micro-ring Resonator using Fe/Co Bistable Molecule

Phase change materials (PCMs) with distinct optical properties at different phases are promising candidates for programmable photonics, optical communication and photonic computing. In this work, we have studied thermo-optic effect in a PCM-based integrated photonic device comprising a film of bistable [Fe2Co2] molecular square complex of Prussian Blue Analogues deposited on an on-chip silicon slot waveguide micro-ring resonator. Herein, we are reporting a large thermo-optic blue-shift of 200 pm/K corresponding to a thermo-optic coefficient of −0.4 RIU/K at room temperature, which is an order of magnitude larger than conventional photonic materials. The thermo-optic coefficient can be thermally tuned to zero at the phase-transition temperature of the bistable molecule