  Multi-spectral frequency combs provide frontier architectures for laser
standoff spectroscopy, optical clockwork, and high-capacity optical
communications. Frequency microcombs, aided by their high-quality resonances
and inherent third-order nonlinear susceptibility, have demonstrated remarkable
impact in frequency metrology and synthesis. However, microcombs are often with
limited spectral bandwidth bounded by the intrinsic second-order chromatic
dispersion and the consequently low intensities at the spectral edges. To
enhance the applications of frequency combs, a spectrally-broad comb generation
scheme is often desired. Here we report coherent satellite clusters in
multi-spectral regenerative frequency microcombs with enhanced intensities at
the octave points and engineered frequency span. Beyond the conventional
bandwidth of parametric oscillation, the regenerative satellites are
facilitated by higher-order dispersion control allowing for
multi-phase-matching in the microcavities. The frequency span of the
multi-spectral regenerative satellites is deterministically controlled from 57
THz to 126 THz by pumping at C- and L- bands. We demonstrate that the
regenerative satellite preserves the coherence with the central comb through
the nonlinear parametric process. We further show the mirrored appearance of
the satellite transition dynamics including each comb state that are
simultaneously observed at the central comb. These multi-spectral regenerative
satellites extend the scope of parametric-based frequency combs and provide a
unique platform with wide applications.
