Strong squeezing from seed-assisted parametric amplification and its gain dependence in SiN microresonators

We demonstrate bright two-mode squeezed states generated in silicon nitride microresonators using integrated seed-assisted optical parametric amplification (OPA). This integrated quantum source produces a bright squeezed quantum frequency comb spanning multiple mode pairs with frequency separations up to 11 THz, and achieves up to 5.6 dB of measured intensity-difference squeezing. We systematically explore how pump and seed detunings, gain and phase-matching conditions of nonlinear interaction influence squeezing performance. These factors extend beyond conventionally known squeezed-state-degradation with optical losses, impacting the achievable squeezing in integrated microresonators. These insights advance the fundamental understanding necessary for practical integrated quantum photonic devices, paving the way toward robust, scalable applications in quantum information processing and quantum-enhanced sensing.