Photonic chip based optical frequency comb using soliton induced Cherenkov radiation

Abstract

Microresonator optical frequency combs have become an actively researched alternative way to generate optical frequency combs. Their key properties are large mode spacings and the potential for photonic integration which is important for applications in different areas ranging from metrology to low-noise RF generation and applications in telecommunication. Discovered in 2007, one main goal has been to achieve a frequency comb that is coherent and spans a spectrum wide enough to be self-referenced. Many important steps in this direction have been achieved. However, the goal of a fully coherent yet wide enough spectrum for self-referencing has not been achieved. Here we report on a frequency comb generated in a silicon nitride (SiN) microresonator that has a repetition rate of 190 GHz and spans 2/3 of an octave, sufficient for self-referencing.