Fig. 1. (a) Schematic configurations of the aMZI chip with input and output ports on its left and right sides, respectively. (b) Microscope image of a part of the aMZI structure. (c) Zoomed-in SEM image of the bending waveguide region. (d) Cross-sectional SEM image of the TFLN waveguide.

Fig. 2. Schematic view of the experimental setup for the aMZI transmission measurements at different temperatures. The data was obtained by the OSA and further recorded and analyzed by one personal computer. Fibers are indicated by green lines.

Fig. 3. Segments of the normalized transmission spectra of a TFLN aMZI at different temperatures (from 290 to 10 K in steps of 10 K).

Fig. 4. Calculated TO coefficient of the TFLN based on the measured transmission spectra from 290 to 10 K. The inset shows the relationship between the central wavelength and the temperature decrement from 290 to 10 K. The purple solid line corresponds to the fitted result.