140  Gbps O-band DAC-less PAM-4 generation enabled by a dual-drive thin-film lithium niobate modulator

DAC-less optical transmitters offer a critical low-power solution for high-speed fronthaul but face severe linearity and chirp constraints on silicon platforms. In this work, we demonstrate a high-performance O-band dual-drive Mach-Zehnder modulator (MZM) based on the thin-film lithium niobate (TFLN) platform. The device exhibits a 3 dB electro-optic bandwidth of 70 GHz. By independently driving the dual arms with binary electrical signals, we realize DAC-less PAM-4 generation at 140 Gbps per lane, with an extinction ratio of 4.92 dB. This demonstration confirms the potential of DUV-processed TFLN modulators as a key enabling technology for energy-efficient, high-speed, and low-latency 6G fronthaul applications.