Characterisation of Silicon (Si) fibre Bragg grating in near-infrared band for strain and temperature sensing

Abstract

This letter describes fibre Bragg grating inscription in crystalline siliconcore fibre using visible light femtosecond laser pulses. The femtosecond pulses at 517 nm propagate through the transparent silica glass cladding and are fully absorbed by the silicon core generating locally high temperatures and stress fields in forming the grating periods. The siliconFBGs were characterised in reflection, calibrated for the first time as strain and temperature sensors and compared with that of FBGs inscribed in common silica fibres.