Two-line-seeded dark-soliton microcomb cloning dynamics in normal-dispersion microresonators

Optical microcombs provide phase-correlated wavelength grids for parallel photonic systems. For applications requiring matched or synchronized combs, relative carrier-frequency and repetition-rate drift between independent sources can degrade comb-line alignment. Here, we numerically investigate two-line-seeded cloning of normal-dispersion dark-soliton microcombs. A transmitter dark-soliton comb is first generated using a localized pump-mode resonance perturbation, and its pump and μ = -1 comb lines are then used as a coherent two-line seed to regenerate a receiver dark-soliton comb without a receiver-side avoided-mode-crossing perturbation. Simulations based on the Lugiato-Lefever equations show that free-spectral-range mismatch induces temporal walk-off, spectral asymmetry, and a reduction of the receiver soliton existence range, defined as the detuning interval over which the cloned dark-soliton state is sustained. Independent control of the two seed-line powers enlarges the receiver soliton existence range from approximately 15 MHz to above 1 GHz in the matched case and maintains a near-GHz best accessible soliton existence range over the tested mismatch range, while the high soliton existence range operating area narrows.