An optical fiber electric field sensor based on polarization-maintaining photonic crystal fiber selectively filled with liquid crystal

This paper presents a liquid crystal selective filling polarization-maintaining photonic crystal fiber (PMPCF) structure for electric field measurement. E7 liquid crystal (LC) is accurately filled into a large hole near the core of the PMPCF to form an internal fiber coupler. When an external voltage is applied, an electric field sensitivity of 1.1137 nm/Vrms is obtained. The device also responds to the frequency of the electric field, and when the frequency of the electric field increases, a blue shift of the transmitted spectrum occurs. The proposed structure has potential application value in the online measurement of electric field value and frequency.