Millimeter-scale Meandered Thin-film Lithium Niobate Modulator with 0.72-\mathrm{V}\ \mathrm{V} \pi$

We present a meandered thin-film lithium niobate modulator with $1-\mu m$-gap T-rails for a strong and direction-controllable electric field. A record-low half-wave voltage of 0.72 V is achieved on a compact footprint of $8\times 1.2\ mm^{2}$.