Zhang Shuangyou, Silver Jonathan M, Bi Toby, Del'Haye Pascal
Max Planck Institute for the Science of Light, 91058, Erlangen, Germany.
National Physical Laboratory (NPL), Teddington, TW11 0LW, UK.
Nat Commun. 2020 Dec 14;11(1):6384. doi: 10.1038/s41467-020-19804-8.
Broadband optical frequency combs are extremely versatile tools for precision spectroscopy, ultrafast ranging, as channel generators for telecom networks, and for many other metrology applications. Here, we demonstrate that the optical spectrum of a soliton microcomb generated in a microresonator can be extended by bichromatic pumping: one laser with a wavelength in the anomalous dispersion regime of the microresonator generates a bright soliton microcomb while another laser in the normal dispersion regime both compensates the thermal effect of the microresonator and generates a repetition-rate-synchronized second frequency comb. Numerical simulations agree well with experimental results and reveal that a bright optical pulse from the second pump is passively formed in the normal dispersion regime and trapped by the primary soliton. In addition, we demonstrate that a dispersive wave can be generated and influenced by cross-phase-modulation-mediated repetition-rate synchronization of the two combs. The demonstrated technique provides an alternative way to generate broadband microcombs and enables the selective enhancement of optical power in specific parts of a comb spectrum.
宽带光学频率梳是用于精密光谱学、超快测距、作为电信网络的信道发生器以及许多其他计量应用的极其通用的工具。在此，我们证明，通过双色泵浦可以扩展在微谐振器中产生的孤子微梳的光谱：一个波长处于微谐振器反常色散区域的激光器产生明亮的孤子微梳，而另一个处于正常色散区域的激光器既补偿微谐振器的热效应，又产生重复频率同步的第二频率梳。数值模拟与实验结果吻合良好，并揭示了来自第二个泵浦的明亮光脉冲在正常色散区域中被动形成并被初级孤子捕获。此外，我们证明了可以通过两个梳的交叉相位调制介导的重复频率同步产生色散波并对其进行影响。所展示的技术提供了一种产生宽带微梳的替代方法，并能够在梳状光谱的特定部分选择性地增强光功率。
