THz Fiber Bragg Grating for Distributed Sensing

This letter reports a fiber Bragg grating for distributed sensing applications fabricated using single-mode optical fiber and a femtosecond laser and interrogated in the terahertz range. A theoretical model of device behavior was derived, which agreed well with experimentally observed device behavior. In order to investigate the utility of terahertz fiber Bragg gratings (THz FBGs) as a sensing modality, temperature tests were conducted. The results demonstrated a sensitivity of -1.32 GHz/ºC and a detection resolution of less than 0.0017 ºC. 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