No abstract

We report a simple and robust all-fiber in-line Fabry-Pérot interferometer (FPI) with an air bubble cavity, which is fabricated by directly splicing a multimode photonic crystal fiber (MPCF) to a conventional single-mode fiber with a commercialized fusion splicer. The air microbubble inserted between the two fibers has two smooth glass-air interfaces separated by a distance as two reflective mirrors of the FPI. Due to the big air holes in the cladding of MPCF and its large numerical aperture, this device has higher signal-to-noise ratio and fringe contrast than that of the FPI based on hollow-core photonic crystal fiber. Experimental results show that the FPI can be used to measure strain in the range of at high temperatures of up to 750 C. Therefore, such an FPI sensor may find important applications in the aeronautics or metallurgy areas.Index Terms-High temperature, optical fiber Fabry-Pérot interferometer (FPI), photonic crystal fiber, strain measurement.

We have constructed a novel refractive index (RI) sensor based on a fiber optic Fabry-Perot interferometer (FPI) by splicing a section of hollow core fiber between a single-mode fiber and a photonic crystal fiber (PCF). Owing to the air holes in the cladding of the PCF, various substances, such as liquids and gases with different RI, can enter or leave the in-fiber air cavity, which makes the device usable as a refractometer. In this paper, the fiber optic FPI sensor has been used to monitor the RI changes of air with different pressures, and the experimental results show that such a sensor has an RI sensitivity of 805.1 microm/RIU, and hysteresis is not observed. Moreover, the easy fabrication method gives the in-fiber refractometer many potential applications in the sensing field.

We report a simple and robust all-fiber in-line Fabry-Perot interferometer (FPI) with bubble cavity, which is fabricated by directly splicing a mutimode photonic crystal fiber to a conventional single mode fiber by using a commercial splicer. The fabrication process only involves fusion splicing and cleaving. The high-temperature strain characteristic of such a device is evaluated and experimental results shows that this FPI can be used as an ideal sensor for precise strain measurement under high temperatures of up to 750℃. Therefore, such a FPI sensor may find important applications in aeronautics or metallurgy areas.

No abstract