A highly sensitive optical fiber strain sensor based on cascaded multimode fiber and photonic crystal fiber

摘要

A highly sensitive optical fiber strain sensor is presented in this work. The structure of the device consists of cascaded multimode fiber (MMF) and photonic crystal fiber (PCF), fusion spliced with single mode fiber (SMF) at both of its ends. As cladding mode is excited at the SMF-MMF interface and coupled back to the fiber core at PCF-SMF interface, the device is essentially a Mach-Zehnder interferometer (MZI). Such a device is robust, simple in fabrication and highly sensitive to strain variation, with a sensitivity of similar to -14.89 pm/mu epsilon.