Broadband High-Sensitivity Thin-Film LiNbO3 Based E-Field Sensor With LF-Shaped Electrode

A novel broadband high-sensitivity optical E-field sensor is proposed in this letter. To solve the problem of bandwidth sensitivity, thin-film LiNbO3 (TFLN) is employed to fabricate the photonic device. Herein, the inductively coupled plasma (ICP) etching methodology using a mixture of Ar and
$\text{C}_{{4}}\text{F}_{{8}}$
is first introduced, which is more effective in etching and helps to sharpen the lateral angle of the LN ridge waveguide. The LF-shaped electrode is designed to improve the performance of the sensor with a bandwidth of 1 MHz to 20 GHz and a sensitivity of 1 mV/m. The volume of the sensor with the package is only
${20}\times {5} \times 5$
mm, which can be utilized in narrow spaces of the weak electromagnetic signal in the wideband frequency range.