Aluminum nitride nanophotonics for beyond-octave soliton microcomb generation and self-referencing

Frequency microcombs, successors to mode-locked laser and fiber combs, enable miniature rulers of light for applications including precision metrology, molecular fingerprinting, exoplanet discoveries. To the frequency ruling function, microcombs must be stabilized by locking their carrier-envelop offset frequency. So far, microcomb stabilization remains compounded elaborate optics external chip, thus evading its scaling benefit. address this challenge, here we demonstrate a nanophotonic chip solution based on aluminum nitride thin films, which simultaneously offer optical Kerr nonlinearity generating octave soliton combs Pockels enabling heterodyne detection The agile dispersion control crystalline III-Nitride photonics permits high-fidelity generation solitons with features 1.5-octave comb span, dual dispersive waves, sub-terahertz repetition rates down 220 gigahertz. These attractive characteristics, aided on-chip phase-matched waveguides, allow full determination Our proof-of-principle demonstration represents an important milestone towards fully-integrated self-locked portable atomic clocks synthesizers.