Periodic pulses of light forming a comb in the frequency domain are widely used for sensing and ranging. The key to the miniaturization of this technology toward chip-integrated solutions is the generation of dissipative solitons in ring-shaped microresonators. Dissipative solitons are stable pulses circulating around the circumference of a nonlinear resonator.
Source:
https://phys.org/news/2021-02-optical-frequency-dimension.html