Electric field sensor using multi-tapered optical fibers and electro-optic polymer

In this paper, an optical electric field sensor using multi-tapered optical fiber and electro-optical polymer is proposed to overcome the shortcomings of the traditional crystal MZI structure electric field sensor, such as complex preparation process, low crystal electro-optic coefficient and high overall price. By using the splitting structure of the multi-tapered optical fiber, the light after the first taper is simultaneously distributed in the core and cladding of the fiber, and the two lights are coupled at the second taper to realize the MZI optical path in a single fiber. Combined with the plasticity and high electro-optic coefficient of the electro-optic polymer, the electro-optical polymer is coated on the outside of the optical fiber. Under the action of external electric field, electro-optic polymer produces electro-optic effect, which results in the change of its refractive index. Due to the existence of evanescent field on the surface of optical fibers, the change of refractive index will affect the light field in the cladding, so electric field sensing can be realized after two optical coupling channels. The feasibility of the scheme of electric field sensor is verified by simulation and experiment.