On-chip multi-timescale spatiotemporal optical synchronization

Area of Science:

• Nonlinear optics
• Topological photonics
• Integrated photonics

Background:

• Mode locking is crucial for advancements in metrology, spectroscopy, and communications.
• Exploring mode locking in nonharmonic, multi-timescale regimes remains a significant challenge.

Purpose of the Study:

• To realize on-chip multi-timescale synchronization using topological photonics.
• To investigate nested mode-locked states with distinct fast and slow timescales.

Main Methods:

• Design of a two-dimensional lattice of 261 coupled silicon nitride ring resonators.
• Observation of multi-timescale mode locking signatures, including pump noise distribution and repetition beats.
• Analysis of edge-confined states dynamics distinct from bulk and single-ring modes.

Main Results:

• Successful realization of nested mode-locked states with fast (~1 THz) and slow (~3 GHz) timescales.
• Observation of quadratic pump noise distribution across azimuthal mode families, confirming theoretical predictions.
• Demonstration of near-transform-limited repetition beats and periodic temporal patterns on the slow timescale.

Conclusions:

• Topological frequency combs offer a robust platform for independently tunable, lattice-scale synchronization.
• This work opens new avenues for exploring the interplay between nonlinearity and topology in integrated photonics.
• The findings pave the way for novel applications in optical metrology, spectroscopy, and communications.