Heterogeneous integrated optical fiber with side nickel core for distributed magnetic field sensing.

A design of a heterogeneous integrated optical fiber with side nickel core (SNCF) has been proposed and demonstrated for distributed fiber-optic magnetic field sensing. Experimental results show that magnetic properties of nickel can be preserved well after the high temperature drawing process. The functionality of the SNCF has been well verified, with the sensitivity for DC magnetic field being up to -2.42 µÎµ/mT (below 8 mT). Besides, the SNCF finally presents magnetostriction saturation under a certain magnetic field, which agrees with the simulation. The proposed direct thermal drawing method to produce metal-heterogeneous integrated optical fiber paves the way for a simple and scalable means of incorporating metallic materials into fibers, as well as providing a promising candidate for long-distance distributed magnetic field sensing.