中心博士研究生舒浩文在UCSB访学期间，与UCSB John Bowers教授课题组关于高效率硅基铝镓砷片上光学频率梳的合作工作 “Ultra-efficient frequency comb generation in AlGaAs-on-insulator microresonators” 近期发表在Nature Communications期刊上，UCSB博士后研究员常林、谢卫强与中心博士研究生舒浩文为共同第一作者。文章提出了一种超低损耗硅基铝镓砷微环谐振腔的设计制备方法，实现了高非线性低损片上微环谐振腔结构，其Q值与之前报道的最优结果相比提升了10倍。基于该谐振腔实现了目前报道最低的片上光学频率梳阈值功率（<36μW），并首次在III-V平台上观测到光孤子台阶。

摘要：Recent advances in nonlinear optics have revolutionized integrated photonics, providing on chip solutions to a wide range of new applications. Currently, state of the art integrated nonlinear photonic devices are mainly based on dielectric material platforms, such as Si3N4 and SiO2. While semiconductor materials feature much higher nonlinear coefficients and convenience in active integration, they have suffered from high waveguide losses that prevent the realization of efficient nonlinear processes on-chip. Here, we challenge this status quo and demonstrate a low loss AlGaAs-on-insulator platform with anomalous dispersion and quality (Q) factors beyond 1.5 × 106. Such a high quality factor, combined with high nonlinear coefficient and small mode volume, enabled us to demonstrate a Kerr frequency comb threshold of only ∼36 μW in a resonator with a 1 THz free spectral range, ∼100 times lower compared to that in previous semiconductor platforms. Moreover, combs with broad spans (>250 nm) have been generated with a pump power of ∼300 μW, which is lower than the threshold power of state-of the-art dielectric micro combs. A soliton-step transition has also been observed for the first time in an AlGaAs resonator.

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Lin Chang, Weiqiang Xie, Haowen Shu, Qi-Fan Yang, Boqiang Shen, Andreas Boes, Jon D. Peters, Warren Jin, Chao Xiang, Songtao Liu, Gregory Moille, Su-Peng Yu, Xingjun Wang, Kartik Srinivasan, Scott B. Papp, Kerry Vahala & John E. Bowers (2020). Ultra-efficient frequency comb generation in AlGaAs-on-insulator microresonators. Nature communications, 11(1), 1-8.