All Fiber Electric Field Sensor Based on Electrical Control of Liquid Crystal Photonic Crystal Fiber

An electric field (E-field) sensor based on liquid crystal (LC) infiltrated photonic crystal fiber (PCF) is proposed and experimentally demonstrated in this paper. Liquid crystals (5CB nematic liquid crystals, NLC) are filled into the cladding air holes of a PCF. A photonic bandgap type waveguide is then formed. Applying an external E-field to the NLC-filled PCF changes the alignment of the LC molecules in the LC layer, which affects the edge wavelength of the photonic bandgap. The E-field sensitivity is about 157.51 nm/kV/mm in the range of 130 V to 220 V (0.65 kV/mm to 1.1 kV/mm). The sensor is lightweight, low-cost, sensitive, and stable, and can be widely used in industrial production.