Construction of Mach-Zehnder interferometer in no-core fiber using single straight in-fiber waveguide

We demonstrated a new fiber in-line Mach-Zehnder interferometer in no-core fiber based on single straight waveguide fabricated by femtosecond laser. The device is simple in structure and fabrication and is robust, and can be used for high temperature and bend sensing, with the sensitivity of of -278.86 pm/°C and 0.28nm/m-1, respectively. Moreover, the free spectral range of the interferometer device can be easily controlled and in a precise manner.