Scalable electro-optic frequency comb generation via dual-frequency-driven cascaded thin-film lithium niobate...

Electro-optic frequency comb (EOFC), featuring high performance, flexibility, and on-chip integrability, has become a key technology for optical communications and precision metrology. In this work, we propose and experimentally demonstrate an efficient EOFC generation scheme on a thin-film lithium niobate (TFLN) platform. By driving cascaded TFLN modulators with two radio frequency (RF) signals at different frequencies and optimizing the driving parameters, we are able to generate an EOFC with a line spacing of 2.5 GHz and 432 comb lines with a flatness of 10 dB. The presented scheme substantially increases the number of comb lines compared to single-tone driving. The proposed approach offers an effective route to overcome the line-number scaling limit of conventional EOFCs, providing a practical path towards high-performance comb sources.