Dark-pulse Kerr combs in linearly coupled microring structures

The generation of dissipative Kerr solitons in microresonators became a milestone in the quest towards a chip-scale frequency comb source. Although successful demonstrations in diverse fields have been made, one outstanding issue with dissipative Kerr solitons is their poor power conversion efficiency. This has a fundamental origin in the need to operate the soliton microcomb at a large frequency detuning. The limited conversion efficiency is a crucial aspect when considering co-integration with chip-scale laser sources or applications that demand higher power per line, such as optical communications