A tunable Mach-Zehnder interferometer based on dual micro-cavity photonic crystal fiber for load measurement

Optical fiber technologies are widely engaged in variety of industries, machines and production lines due to their precise results and low cost. Optical sensors are fabricated using different types of optical fibers. In this paper, a new fabrication approach of, in-fiber, tunable Mach-Zehnder interferometer with dual micro-cavities using a photonic crystal fiber (PCF) has been proposed for load measurement application. A large mode area (LMA-10) PCF is used to splice between two equal lengths of single-mode fibers using fusion splicing technique. Different parameters such as arc power, length of the PCF and the overlap gap between samples have been considered to control the fabrication process. Ellipsoidal shape micro-cavities were experimentally achieved parallel to the propagation axis having dimensions of (24.92-62.32) mu m of width and (3.82-18.2) mu m of length. Results showed that higher sensitivity values of 0.15 nm/N and 0.32 nm/N were achieved with elliptical width of 18.2 mu m. The simplicity of sensor fabrication process, controlled parameters of cavity creation, small and compact size and high sensitivity of large mode area that the PCFs exhibit, add more advantage for load measurement applications.