Optical switch with an ultralow DC drift based on thin-film lithium tantalate.

We present an electro-optic (EO) switch with ultralow DC drift on a thin-film lithium tantalate (TFLT) platform, even with SiO ₂ cladding and without post-annealing processes. The flat V _π and EO responses have been measured across various driving frequencies, input optical powers, and temperatures. Stable optical switching is achievable in the low-frequency range. The experiment also demonstrated superior long-term stability (up to 2 h) compared to thin-film lithium niobate optical switches under similar on-chip optical power conditions (around -8 dBm).