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

Abstract

AbstractA 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$$\hbox {Sb}_{2} \hbox {S}_{3}$$Sb2S3optically 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$$\hbox {Sb}_{2}\hbox {S}_{3}$$Sb2S3to be 3.4 x$$10^{-4}\hbox {K}^{-1}$$10-4K-1and 0.1 x 10$$^{-4}\hbox {K}^{-1}$$-4K-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 ($$-5.9$$-5.9to 5.1 dBm) with a modulation in effective refractive index ranging from +5.23 x$$10^{-5}$$10-5to$$-1.20$$-1.20x 10$$^{-4}$$-4. This work experimentally verifies optical phase modifications and permanent trimming of$$\hbox {Sb}_{2}\hbox {S}_{3}$$Sb2S3, 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.