Inverse-designed LNOI microring electric field sensor

We designed a novel compact micro-ring electric field sensor based on the thin-film lithium niobite on insulator (LNOI) platform. By leveraging the method of inverse design based on topology-optimized algorithm, a remarkable micro-ring detector with a bending radius of 6 μm has been achieved, resulting in an order of magnitude reduction in loss compared to conventional bends. The designed detector achieves an ultra-compact footprint of 13.22 μm × 22 μm with a relatively flat frequency response across the 50 Hz - 1.95 GHz. At the wavelength of 1550.75 nm, the detector achieves an impressive maximum detectable electric field of 4×10^7 V/m, with a minimum detectable electric field value of 4 kV/m when the maintaining a linear dynamic range of 80 dB for the system. The compact size and electrode-free design of the proposed sensor enable seamless integration into chips and wearable devices, catering to the growing demands of high-field strength electric field measurements in smart power equipment and grid operations. Furthermore, this work represents a pioneering effort in developing a micro-ring electric field sensor using inverse design methodology and opens up new method for advanced sensing applications, paving the way for extensive utilization in future modern photonic integrated circuits.