Thermo-optic tuning of silicon nitride microring resonators with low loss non-volatile $$\hbox {Sb}_{2}\hbox {S}_{3}$$ Sb 2 S 3 phase change material

Abstract

Abstract A new family of phase change material based on antimony has recently been explored for applications in near-IR tunable photonics due to its wide bandgap, manifested as broadband transparency from visible to NIR wavelengths. Here, we characterize $$\hbox {Sb}_{2} \hbox {S}_{3}$$ Sb 2 S 3 optically and demonstrate the integration of this phase change material in a silicon nitride platform using a microring resonator that can be thermally tuned using the amorphous and crystalline states of the phase change material, achieving extinction ratios of up to 18 dB in the C-band. We extract the thermo-optic coefficient of the amorphous and crystalline states of the $$\hbox {Sb}_{2}\hbox {S}_{3}$$ Sb 2 S 3 to be 3.4 x $$10^{-4}\hbox {K}^{-1}$$ 10 - 4 K - 1 and 0.1 x 10 $$^{-4}\hbox {K}^{-1}$$ - 4 K - 1 , respectively. Additionally, we detail the first observation of bi-directional shifting for permanent trimming of a non-volatile switch using continuous wave (CW) laser exposure ( $$-5.9$$ - 5.9 to 5.1 dBm) with a modulation in effective refractive index ranging from +5.23 x $$10^{-5}$$ 10 - 5 to $$-1.20$$ - 1.20 x 10 $$^{-4}$$ - 4 . This work experimentally verifies optical phase modifications and permanent trimming of $$\hbox {Sb}_{2}\hbox {S}_{3}$$ Sb 2 S 3 , enabling potential applications such as optically controlled memories and weights for neuromorphic architecture and high density switch matrix using a multi-layer PECVD based photonic integrated circuit.