Dispersion-free broadband quantum optical frequency combs using inverse design
Phys. Rev. A 113, 053528 – Published 22 May, 2026
DOI: https://doi.org/10.1103/38dj-gwk6
Abstract
Quantum optical frequency combs generated using optical nonlinearities in integrated photonic resonators provide a versatile paradigm that leverages multiple spectral modes to generate complex quantum states of light. Nevertheless, the maximum number of spectral modes generated by integrated resonators is severely limited by dispersion, which drastically reduces the brightness of the comb lines that are further away from the pumped mode. Here we theoretically propose and numerically demonstrate an inverse-designed ring resonator that can generate highly multimodal, dispersion-free quantum combs with uniformly bright and equally spaced comb lines. More specifically, we utilize a superposition of periodic modulations of the ring resonator waveguide to couple the clockwise and counterclockwise propagating modes of the ring, thereby creating frequency splittings that balance dispersion. Using phase-controlled bidirectional pumping, we show that this approach can be used to generate both discrete-variable quantum combs of entangled photon pairs and continuous-variable quantum combs of two-mode squeezed light. Moreover, this approach is material agnostic and applicable to resonators operating in both anomalous and normal dispersion regimes. Our design closely follows the inverse-designed classical combs and optical parametric oscillators that have been recently implemented using similar modulated ring resonators and is therefore readily implementable using existing fabrication technology. These results provide a practical pathway to highly multimodal and bright quantum comb sources for frequency-encoded quantum communication and computation protocols.
