Bragg Gratings in ZEONEX Microstructured Polymer Optical Fiber With 266-nm Nd:YAG Laser

We present the first fiber Bragg gratings (FBGs) inscription in ZEONEX-480R microstructured polymer optical fiber (POF) by employing the fourth harmonic (266 nm) of a Nd:YAG laser system. The gratings were produced in the
${L}$
-band region by the phase mask method, in 270-
$\mu \text{m}$
diameter POF samples connectorized with ferrule connectors (FCs). The results of three produced gratings are reported, showing good stability over 99 d. The sensing response to strain, temperature, and humidity was analyzed and confirmed the good stability and performance of the inscribed gratings in this polymer fiber. These results are promising from the point of view that gratings can be produced in ZEONEX-480R microstructured POF (mPOF) with the 266-nm wavelength, which is an alternative and viable cost-effective solution. Additionally, the production of gratings in this type of polymer fiber, with a relatively high diameter, shows great potential for a wide variety of sensing applications.