Choi Gwangho, Su Judith
Wyant College of Optical Sciences, The University of Arizona, Tucson, AZ 85721, United States of America.
Department of Biomedical Engineering, The University of Arizona, Tucson, AZ 85721, United States of America.
JPhys Photonics. 2023 Jan 1;5(1):014001. doi: 10.1088/2515-7647/aca8e1. Epub 2022 Dec 21.
Generating a coherent optical frequency comb at an arbitrary wavelength is important for fields such as precision spectroscopy and optical communications. Dark solitons which are coherent states of optical frequency combs in normal dispersion microresonators can extend the operating wavelength range of these combs. While the existence and dynamics of dark solitons has been examined extensively, requirements for the modal interaction for accessing the soliton state in the presence of a strong Raman interaction at near visible wavelengths has been less explored. Here, analysis on the parametric and Raman gain in a silica microresonator is performed, revealing that four-wave mixing parametric gain which can be created by a modal-interaction-aided additional frequency shift is able to exceed the Raman gain. The existence range of the dark soliton is analyzed as a function of pump power and detuning for given modal coupling conditions. We anticipate these results will benefit fields requiring optical frequency combs with high efficiency and selectable wavelength such as biosensing applications using silica microcavities that have a strong Raman gain in the normal dispersion regime.
在任意波长产生相干光频梳对于精密光谱学和光通信等领域至关重要。暗孤子作为正常色散微谐振器中光频梳的相干态，可扩展这些光频梳的工作波长范围。虽然暗孤子的存在和动力学已得到广泛研究，但在近可见光波长存在强拉曼相互作用的情况下，进入孤子态所需的模式相互作用的要求却较少被探索。在此，对二氧化硅微谐振器中的参量增益和拉曼增益进行了分析，结果表明，由模式相互作用辅助的额外频移所产生的四波混频参量增益能够超过拉曼增益。在给定的模式耦合条件下，分析了暗孤子的存在范围作为泵浦功率和失谐的函数。我们预计这些结果将有益于需要高效且波长可选择的光频梳的领域，例如使用在正常色散 regime 中具有强拉曼增益的二氧化硅微腔的生物传感应用。
