Optical frequency combs based on mode-locked laser sources have provided unprecedented measurement capabilities for optical frequencies, enabling new applications in a wide range of topics that include atomic clocks, ultracold gases, molecular fingerprinting, microwave photonics, and astronomy. In recent years a new optical frequency comb generation principle has emerged, that does not rely on conventional mode-locked lasers but instead uses parametric frequency conversion in high-Q microresonators. This approach not only offers compactness and chip-scale integration, but moreover provides direct access to high repetition rates in the range of 10-1000 GHz. Here we review this emerging technology, which yields opportunities for novel technologies as well as for fundamental science.
Citation: Science Magazine
Pub Type: Journals
frequency comb, microresonator, mode-locked laser