Multimode squeezing in soliton crystal microcombs

Abstract

Soliton microcombs are self-organized pulses of light sustained in driven Kerr microresonators, intensively studied for applications in integrated photonic technologies and for their rich nonlinear dynamics. In this work, we theoretically study the collective dynamics of the quantum fluctuations of soliton microcombs. We find that the mean field of a dissipative Kerr soliton crystal is accompanied by pulses of squeezed multimode vacuum and derives its operational stability from the strong detuning of the below-threshold parametric process. We present a photonic architecture that enables independent control of the above- and below-threshold states and achieves a high degree of squeezing (>15dB) in the output waveguide with realistic losses. Our work elucidates the quantum dynamics of formation and annihilation in dissipative Kerr soliton systems, and establishes a pathway for the realization of a practical integrated source of multimode squeezed light.