Relief Bragg reflectors inscribed on the capillary walls of solid‐core photonic crystal fibers

The inscription of relief Bragg grating reflectors on the capillary walls of a solid‐core photonic crystal fiber (PCF) using laser radiation is presented. The inscription method followed is based on the infiltration and adsorption of a thin layer of toluene on the capillaries of the PCF and the subsequent exposure of the infiltrated fiber using 248‐nm excimer laser radiation and phase mask interference. Gratings are characterized spectrally and by scanning electron microscopy while their sensing capabilities are exemplified by infiltrating them with organic solvents. Thermal studies revealed that the gratings exhibit high thermal endurance characteristics, withstanding tens of hours annealing at 950°C.