Analysis of parameter combinations for optimal soliton microcomb generation efficiency in a simple single-cavity scheme

Dissipative Kerr solitons generated in high-$Q$ optical microresonators provide unique opportunities for different up-to-date applications. Increasing the generation efficiency of such signals is a problem of paramount importance. We perform a comprehensive analytical and numerical analysis using a simple single-cavity scheme. It is revealed that in order to obtain high pump-to-comb conversion efficiency such parameters as coupling rate, pump amplitude, detuning, and microresonator second-order dispersion should not be considered individually, only in the aggregate. The dependence of the optimal coupling rate on the pump power is shown, in addition to the trade-off relations balancing the efficiency versus the number of comb lines. Combining analytical predictions and numerical simulations, we find optimal conditions for the maximal pump-to-comb conversion efficiency (up to 100%) in the cases of free-running and self-injection-locked pump lasers. The discrepancy between numerical and analytical solutions and methods to increase the total comb power are also discussed.