Demonstration of a stable ultrafast laser based on a nonlinear microcavity

TLDR

Ultrashort pulsed lasers based on mode‑locking have impacted many fields for five decades, and recent use of high‑quality resonators for optical combs suggests that phase‑locking their modes could enable precision optical clocks and other high‑spectral‑quality applications. Here we demonstrate the first mode‑locked laser based on a microcavity resonator. It operates via a new filter‑driven four‑wave mixing method using a CMOS‑compatible high‑Q microring resonator. The laser achieves stable self‑starting oscillation with negligible amplitude noise at ultrahigh repetition rates and spectral linewidths below 130 kHz.

Abstract

Ultrashort pulsed lasers, operating through the phenomenon of mode-locking, have had a significant role in many facets of our society for 50 years, for example, in the way we exchange information, measure and diagnose diseases, process materials, and in many other applications. Recently, high-quality resonators have been exploited to demonstrate optical combs. The ability to phase-lock their modes would allow mode-locked lasers to benefit from their high optical spectral quality, helping to realize novel sources such as precision optical clocks for applications in metrology, telecommunication, microchip-computing, and many other areas. Here we demonstrate the first mode-locked laser based on a microcavity resonator. It operates via a new mode-locking method, which we term filter-driven four-wave mixing, and is based on a CMOS-compatible high quality factor microring resonator. It achieves stable self-starting oscillation with negligible amplitude noise at ultrahigh repetition rates, and spectral linewidths well below 130 kHz.