Microstructured Polymer Optical Fiber Gratings and Sensors

This chapter describes the realization of microstructured polymer optical fibers Bragg gratings (mPOFBGs) and their use in various sensing applications. Different grating inscription techniques based on different lasers used in recording grating in mPOF are presented. Grating inscription in mPOFs can be a challenging task compared to step index fibers because the microstructured cladding holes introduce scattering preventing the laser from reaching the core of the fiber easily. Inscription of gratings in mPOFs fabricated from different polymer materials such as Topas, Zeonex, Polycarbonate (PC) is discussed, and their optical and sensing performance is directly compared with the widely used poly(methylmethacrylate)(PMMA). The progress on fabrication of gratings in different types of mPOFs is presented in terms of grating inscription time, strength, and Bragg wavelengths. This chapter also describes the annealing process of mPOFs or mPOFBGs which is one of the curtail step in the development of stable mPOFBG sensors. The different annealing methods that have been applied by the research community are also presented. In addition, an overview on strain, humidity, temperature, pressure, and acceleration sensors developed from mPOFBGs is provided. A direct comparison in terms of their sensitivity, sensing range, and their performance in general is presented. Finally, the way to improve the development of stable mPOFBG sensors and widen their application areas is briefly discussed.