Currently, integrated combs primarily rely on the Kerr effect, electro-optic (EO) modulation, or mode-locking (ML) mechanisms, each offering distinct advantages and limitations, leading to broad bandwidth and tunability always being at odds with each other. To achieve both of these characteristics, some discrete systems are inevitable. First, InP-based ML laser and lithium niobate-based EO modulator are used to achieve a hybrid comb with low consumption, broad bandwidth, and tunability simultaneously. Furthermore, the heterogeneous integration via ultra-low-loss photonic wire bonding is proposed. The solution addresses the trade-off of integrated combs and allows chip-scale implementation for photonic applications.
Zhang et al. (Mon,) studied this question.