Tunable Degenerate\nOptical Parametric Oscillation\nwith Coupled Microresonators

Microresonator-based degenerate optical parametric oscillation\n(DOPO) has recently been explored as a compelling platform for all-optical\ncomputing and quantum information applications such as truly random\nnumber generation and the production of squeezed states of light.\nEmerging research has highlighted the potential of coupled microresonators,\nor photonic molecules, as a novel avenue for spectral engineering,\nunlocking an extra degree of freedom for the optimization of four-wave\nmixing interactions. Here, we demonstrate a single tunable DOPO within\nthe coupled modes of a silicon nitride triplet-state photonic molecule.\nOur design introduces a distinctive mechanism for spectral engineering,\nusing microheaters to individually tune the resonance spectral positions,\nthus enabling dynamic local dispersion control within the coupled\nmodes. We successfully generated a DOPO signal with active efficiency\ncontrol and explored the optical mode spacing in the tens of gigahertz\nrange to use native phase-locked optical pumps driven by a radio frequency\nsource.