Q. X. Li, Qiyuan Yi, Aolong Sun, Chenglin Shang, Yiqi Dai, Sizhe Xing, Jinlai Cui, Yupeng Zhu, Jiayi Li, J. Zheng, J. Zhang, Nan Chi, An Pan, Cheng Zeng, Jinsong Xia, Shuang Zheng, Li Shen, Minming Zhang
The escalating capacity limitations of conventional near-infrared telecommunication bands have spurred urgent investigations into wide-band optical communication systems spanning from the near-infrared to mid-infrared regimes. This has motivated the development of optical components combining broadband bandwidth with high-speed operation. The state-of-the-art modulators face challenges in achieving broad operational bandwidth due to waveguide dispersion and velocity mismatch. Here we demonstrate a thin-film lithium niobate (TFLN) electro-optic (EO) modulator with an unprecedented 800-nm operational bandwidth, covering the full O-U telecom bands and extending into the 2-μm regime. The TFLN modulator exhibits >67 GHz EO bandwidth across O-U bands (~100 GHz at O-/S-/C-/L-bands) and >50 GHz at 2-μm band. It enables single-lane exceeding 240 Gbps PAM-4 transmission across O-U bands and a record 170 Gbps PAM-4 transmission at 2-μm band. This breakthrough establishes TFLN as a compelling platform for multispectral photonics, bridging conventional telecom infrastructure with emerging 2-μm technologies for next-generation optical communications. This work demonstrates a thin-film lithium niobate modulator with an 800-nm operational bandwidth covering from near- to mid-infrared region, enabling single-lane 240 Gbps and 170 Gbps PAM-4 transmission at all O-U bands and 2-μm band, respectively.