Monolithic electric field control of a grating coupler for finely tuning wavelength, efficiency, and bandwidth

In this Letter, we propose a Pb(In_1/2Nb_1/2)O₃-Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃-On-Insulator (PIN-PMN-PTOI) based apodized grating coupler through finite-difference time-domain (FDTD) simulations. By leveraging the ultrahigh electro-optic coefficient of PIN-PMN-PT single crystal, we demonstrate precise control over the effective refractive index, thereby fine-tuning the central wavelength, enhancing coupling efficiency (CE) and 3-dB bandwidth. Simulation results reveal that, under an external electric field, the center wavelength can be tuned from 1544.84 nm to 1553.36 nm, while the CE remains above 80%. The CE can be improved by 5.9%; the 3-dB bandwidth can be increased by 2.1 nm at 1550 nm. Our results show that PIN-PMN-PTOI-based gratings are promising for large-scale photonic chip integration with high CE and large bandwidth.