  On-chip manipulation of single resonance over broad background comb spectra
of microring resonators is indispensable, ranging from tailoring laser
emission, optical signal processing to non-classical light generation, yet
challenging without scarifying the quality factor or inducing additional
dispersive effects. Here, we propose an experimentally feasible platform to
realize on-chip selective depletion of single resonance in microring with
decoupled dispersion and dissipation, which are usually entangled by
Kramer-Kroning relation. Thanks to the existence of non-Hermitian singularity,
unsplit but significantly increased dissipation of the selected resonance is
achieved due to the simultaneous collapse of eigenvalues and eigenvectors,
fitting elegantly the requirement of pure single-mode depletion. With delicate
yet experimentally feasible parameters, we show explicit evidence of modulation
instability as well as deterministic single soliton generation in
microresonators induced by depletion in normal and anomalous dispersion regime,
respectively. Our findings connect non-Hermitian singularities to wide range of
applications associated with selective single mode manipulation in microwave
photonics, quantum optics, ultrafast optics and beyond.
