Terahertz Fiber Bragg Grating for Distributed Sensing

This letter reports a fiber Bragg grating (FBG) for distributed sensing applications fabricated using single-mode optical fiber and a femtosecond laser and interrogated in the terahertz (THz) range. A theoretical model of device behavior was derived, which agreed well with experimentally observed device behavior. In order to investigate the utility of THZ FBGs (THz FBGs) as a sensing modality, temperature tests were conducted. The results demonstrated a sensitivity of -1.32 GHz/°C and a detection resolution of <;0.0017 °C. A temperature distribution test was also conducted using a THz FBG, demonstrating its potential as a distributed sensing platform with high spatial resolution. The feasibility of interrogating THz FBGs using narrow interrogation bandwidths was also experimentally shown.