Photosensitivity of Polypropylene No-Core Optical Fibers Using 248nm Laser Radiation

The adoption of polymer optical fibers in a great number of sensing and telecom applications has prompted the study of their photosensitivity using laser radiation [1]. Polypropylene (PP) is a now emerging optical material which is characterised by good optical transmission in the visible and telecom bands, yet of excellent chemical durability, tensibility and high potential for being used in the THz wavelength band. Herein, we investigate the photosensitivity of polypropylene no-core optical fibers using 248nm excimer laser radiation, while performing Bragg grating recording. In the same time, a new photosensitisation approach is presented by means of toluene in-diffusion in the PP matrix, for augmenting photosensitivity yield at the specific irradiation wavelength [2]. Toluene exhibits higher optical absorption than the PP matrix at the wavelength of 248nm, also acting as a plasticiser into the polymeric matrix, improving macromolecular mobility, thus, laser induced structural modifications.