Reconfigurable Non-Hermitian Soliton Combs using Dissipative Couplings and Topological Windings

Abstract: The emergence of dissipative Kerr solitons (DKS) in nonlinear resonators has revolutionized the generation of on-chip coherent optical frequency combs. The formation of DKS in conventional single resonators hinges on balancing the resonator dissipation against the parametric gain and balancing the resonator dispersion against the resonance frequency shifts introduced by the Kerr nonlinearity. Here, we theoretically introduce a new class of non-Hermitian soliton combs that are enabled by engineering the dissipation and dispersion of a coupled resonator array with nonreciprocal couplings. We show that these non-Hermitian soliton combs allow unprecedented post-fabrication agile reconfigurability of the soliton comb spectrum, where the number of comb lines, as well as their frequency spacing, can be drastically tuned by simply tuning the hopping phases between resonators. Such reconfigurable non-Hermitian combs generated using coupled resonator arrays could enable new functionalities for a multitude of comb applications.