Microfiber Bragg grating inscribed using 193nm excimer laser for refractive index sensing

Abstract

The inscription of fiber Bragg gratings was demonstrated by 193 nm ArF excimer laser in microfibers drawn from the standard single mode telecommunication fiber. Fiber Bragg gratings are directly inscribed in a series of microfibers with diameter ranged from ~10μm to 3.3 μm without any treatment to photosensitize the microfibers such as hydrogen loading, etc. Four reflection peaks are observed where three correspond to high order mode resonances. The resonance wavelength depends on the fiber diameter and it sharply blueshifts when the diameter is decreased below 10 μm. The gratings are characterized for their response to ambient refractive index. The higher order mode resonance exhibits higher sensitivity to refractive index.