Electric-field sensor based on propylene carbonate cladding microfiber sagnac loop interferometer

Abstract

Optical microfiber with diameter of wavelength scale has gained numerous successful applications in many fields, as it exhibits a number of unique characteristics and excellent optical properties such as strong confinement, physical flexibility, large evanescent fields, extreme configurability, and high robustness. In this letter, we propose a compact microfiber-based electric field sensor, which consists of a single-mode microfiber sagnac loop interferometer (SMSLI) and propylene carbonate. Owing to Kerr electro-optic effect of propylene carbonate, the refractive index (RI) of propylene carbonate cladding in the twist area of SMSLI will be changed by the applied electric field, which induces a shift of the interference pattern of SMSLI. Hence, the external electric field can be demodulated by measuring the variation of the transmission spectra of SMSLI. The feasibility of the proposed sensor is verified by detecting alternating electric field with frequency of 50 Hz and impulse electric field with duration time of 200 μs.