Periodically poled thin film lithium niobate microring resonators with a second-harmonic generation efficiency of 250,000 %/W

Published on 2019-11-21T20:38:18Z (GMT) by
Lithium niobate (LN), dubbed by many as the silicon of photonics, has recently risen to the forefront of chip-scale nonlinear optics research since its demonstration as an ultralow-loss integrated photonics platform. Due to its significant quadratic nonlinearity χ², LN inspires many important applications such as second-harmonic generation (SHG), spontaneous parametric down-conversion, and optical parametric oscillation. Here, we demonstrate high-efficiency SHG in dual-resonant, periodically poled z-cut LN microrings, where quasi-phase matching is realized by field-assisted domain engineering. Meanwhile, dual-band operation is accessed by optimizing the coupling conditions in fundamental and second-harmonic bands via a single pulley waveguide. As a result, when pumping a periodically poled LN microring in the low power regime at around 1617nm, an on-chip SHG efficiency of 250,000%/W is achieved, a state-of-the-art value reported among current integrated photonics platforms. An absolute conversion efficiency of 15% is recorded with a low pump power of 115μW in the waveguide. Such periodically poled LN microrings also present a versatile platform for other cavity-enhanced quasi-phase matched χ² nonlinear optical processes.

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Tang, Hong; Lu, Juanjuan; Surya, Joshua; Liu, Xianwen; Bruch, Alexander; Gong, Zheng; et al. (2019): Periodically poled thin film lithium niobate microring resonators with a second-harmonic generation efficiency of 250,000 %/W. The Optical Society. Collection. https://doi.org/10.6084/m9.figshare.c.4717562.v1