Ambient index sensor using a Sagnac interferometer based on a D-shaped polarization maintaining fiber

Sagnac interferometer based on a tapered polarization-maintaining fiber for measurement of ambient index

“…In order to measure an external RI, removal of the fiber cladding is required to increase the evanescent field interaction with the surrounding environment. This concept has been recently demonstrated by using the side-polishing or etching process [5,6]. In both case, fabrication processes are rather complicated as well as the durability for the sensing application is severely degraded.…”