Thin-film lithium tantalate electro-optic modulator with balanced bandwidth-voltage and low DC drift

We demonstrate a thin-film lithium tantalate (TFLT) Mach-Zehnder modulator with balanced bandwidth-voltage and low DC drift. Precise waveguide geometry optimization yields a 3-dB bandwidth (BW) > 67 GHz and a half-wave voltage-length product ( V π L ) of 2.4 V·cm, resulting in a higher BW/ V π 2 compared to the previously reported TFLT modulators. The device also shows excellent operational stability, with its V π remaining stable across a wide range of driving frequencies and power drift below 1 dB over 60 minutes. Furthermore, we developwhat we believe is a novel and stable measurement technique which employs a cascaded dual-ring modulation structure to quantitatively assess the DC drift, confirming the long-term viability of TFLT modulators for high-speed, stable, and low-power integrated photonics.