Abstract

The microresonator-based soliton microcomb has shown a promising future in many applications. In this work, we report the fabrication of high quality (Q) Si₃N₄ microring resonators for soliton microcomb generation. By developing the fabrication process with crack isolation trenches and annealing, we can deposit thick stoichiometric Si₃N₄ film of 800 nm without cracks in the central area. The highest intrinsic Q of the Si₃N₄ microring obtained in our experiments is about 6×10⁶, corresponding to a propagation loss as low as 0.058 dBm/cm. With such a high Q film, we fabricate microrings with the anomalous dispersion and demonstrate the generation of soliton microcombs with 100 mW on-chip pump power, with an optical parametric oscillation threshold of only 13.4 mW. Our Si₃N₄ integrated chip provides an ideal platform for researches and applications of nonlinear photonics and integrated photonics.

© 2022 Chinese Laser Press

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