Balloon-like micro-displacement sensor based on chaotic correlation fiber loop ring-down system with loss compensation

Abstract

We demonstrate the micro-displacement sensing using the balloon-like optical fiber to the chaotic correlation fiber loop ring down system. The balloon-like fiber is made of the bent single-mode fiber stripped of a length of coating layer to the phase difference between the core and cladding mode by the interferometer. We analyzed the displacement sensing characteristics of the balloon-like fiber used as a sensing unit theoretically and experimentally. Due to the large bending curvature of the balloon-like fiber, the loss compensation chaotic correlation fiber loop ring down system is used for sensing. The sensing characteristics of balloon-like fibers of different sizes are compared and the influence of cavity length is studied. The result shows that the balloon-like structure with a total length of 4.5 cm embodies superior sensing performance, and its maximum sensitivity can reach −0.38 μs^-1μm⁻¹ when the cavity length is set as 11.95 m. The balloon-like structure makes up for the shortcomings of the optical fiber loop ring down system in high-sensitivity micro-displacement sensing detection.