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arXiv · 2111.10856

Octave-spanning microcomb generation in 4H-silicon-carbide-on-insulator photonics platform

Lutong Cai·Jingwei Li·Ruixuan Wang·Qing Li
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Abstract

Silicon carbide has recently emerged as a promising photonics material due to its unique properties, including possessing strong second- and third-order nonlinear coefficients and hosting various color centers that can be utilized for a wealth of quantum applications. Here, we report the design and demonstration of octave-spanning microcombs in a 4H-silicon-carbide-on-insulator platform for the first time. Such broadband operation is enabled by optimized nanofabrication achieving >1 million intrinsic quality factors in a 36-$\mu$m-radius microring resonator, and careful dispersion engineering by investigating the dispersion properties of different mode families. For example, for the fundamental transverse-electric mode whose dispersion can be tailored by simply varying the microring waveguide width, we realized a microcomb spectrum covering the wavelength range from 1100 nm to 2400 nm with an on-chip power near 120 mW. While the observed comb state is verified to be chaotic and not soliton, attaining such a large bandwidth is a crucial step towards realizing $f$-2$f$ self-referencing. In addition, we have also observed coherent soliton-crystal state for the fundamental transverse-magnetic mode, which exhibits stronger dispersion than the fundamental transverse-electric mode and hence a narrower bandwidth.

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Lutong Cai, Jingwei Li, Ruixuan Wang, Qing Li. 2021-11-21. Octave-spanning microcomb generation in 4H-silicon-carbide-on-insulator photonics platform. https://arxiv.org/abs/2111.10856

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