Phase-controlled nonlinear dynamics and bistability in a non-Hermitian silicon microresonator

We investigate a silicon microresonator with tunable Hermitian and non-Hermitian coupling between the counterpropagating modes, enabled by integrated phase shifters for intensity and phase control. Phase tuning allows control of nonlinear behaviors such as bistability, self-pulsing, and transitions between stationary and quasi-stationary states. The system shows strong path dependence: forward and backward phase sweeps over the same 2π range produce different responses, indicating memory effects arising from nonlinear light–matter interaction and non-Hermitian coupling. Modeling links these features to a global bifurcation involving saddle-node annihilation and a distant limit cycle. The DRUM (Dynamically Reconfigurable Unified Microresonator) provides a reconfigurable platform for complex nonlinear dynamics relevant to neuromorphic and optical information processing.