High-Power Optical Parametric Oscillators in Silicon Nitride

Optical parametric oscillators (OPOs) that rely on third-order nonlinearity convert two pump photons of the same frequency into a signal photon with a higher frequency and an idler photon with a lower frequency. These OPOs are commonly utilized in applications such as frequency conversion, tunable laser sources, and quantum optic s. Silicon nitride optical microresonators, known for their high nonlinearity and low propagation loss, are particularly effective at enhancing intracavity light and facilitating nonlinear interactions [1]. However, achieving high-power output in on-chip OPOs has been challenging due to mode competition caused by cascaded four-wave mixing at high pump powers. Common strategies to suppress mode competition include reducing the microresonator size to increase the mode frequency spacing [2], using hybrid modes to generate OPOs [3], and leveraging the bound states in the continuum (BIC) effect to induce wavelength-periodic losses [4]. In this work, we optimize the coupling strength, pump power, and pump-cavity detuning to maximize the output signal power of BIC-based OPOs.