| The two rings in the image are microresonators. The bigger ring is the one where the microcomb is generated. The microcomb is formed by a pulse of light – here illustrated with a red spike and also known as a soliton - that recirculates in the cavity forever. The key aspect is that the smaller ring helps in coupling the light from the straight waveguide, illustrated by the straight orange line at the bottom, into the bigger ring. In other words, it behaves as impedance matching, and therefore the soliton is generated more efficiently. Credit: Óskar Helgason |
