Adiabatic frequency conversion (AFC) in add-drop resonators holds promise for enhancing energy efficiency in photonic applications. This theoretical study investigates the conditions for optimizing the energy efficiency of the drop port within an add-drop resonator configuration. The analysis considers both fixed input pulse shapes and continuous wave inputs, taking into account AFC's relative timescales. Specifically, the critical coupling regime is explored, and it is observed that the extrinsic decay rates into the drop port and through port converge to nearly equal values, thereby maximizing drop port efficiency. Moreover, when a global parameter is swept, it is demonstrated that the maximal efficiency of the drop port is achieved when the extrinsic decay rates of both ports are equal. This optimization strategy extends to scenarios involving continuous wave inputs as well. These findings provide valuable insights for designing high-performance add-drop resonators and advancing the practical implementation of AFC in photonic systems.
