Introduction . Efficient coupling between waveguides and resonators is of critical importance in integrated photonic systems, but its implementation is difficult due to the variability of the resonator properties as a result of variations in the fabrication process and external conditions. The most effective excitation is achieved at the critical coupling condition when the intrinsic loss rate \({\kappa }_{i}\)of the resonator is matched to the external coupling rate \({\kappa }_{ex...