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arXiv · 2401.10160

Phase-stabilised self-injection-locked microcomb

Thibault Wildi·Alexander E. Ulanov·Thibault Voumard·Bastian Ruhnke·Tobias Herr
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Abstract

Microresonator frequency combs (microcombs) hold great potential for precision metrology within a compact form factor, impacting a wide range of applications such as point-of-care diagnostics, environmental monitoring, time-keeping, navigation and astronomy. Through the principle of self-injection locking, electrically-driven chip-based microcombs with minimal complexity are now feasible. However, phase-stabilisation of such self-injection-locked microcombs, a prerequisite for metrological frequency comb, has not yet been attained. Here, we address this critical need by demonstrating full phase-stabilisation of a self-injection-locked microcomb. The microresonator is implemented in a silicon nitride photonic chip, and by controlling a pump laser diode and a microheater with low voltage signals (less than 1.5 V), we achieve independent control of the comb's offset and repetition rate frequencies. Both actuators reach a bandwidth of over 100 kHz, enabling phase-locking of the microcomb to external frequency references. These results establish photonic chip-based, self-injection-locked microcombs as low-complexity yet versatile sources for coherent precision metrology in emerging applications.

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Thibault Wildi, Alexander E. Ulanov, Thibault Voumard, Bastian Ruhnke, Tobias Herr. 2024-01-18. Phase-stabilised self-injection-locked microcomb. https://doi.org/10.1038/s41467-024-50842-8

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