Dual FBGs, one solution: THz radiation and multi-sensing innovation

A dual short period fiber Bragg grating (D-FBG) device was devised, whereby one FBG was inscribed inside the core and the other within the cladding, enabling the reflection of two distinct wavelengths. The design presented in this study demonstrates versatility by using both core and cladding FBGs to provide multi-sensing capabilities. COMSOL was used to realize the proposed design in this work. The core grating had a reflected frequency of 199.345 THz, while that of the cladding was at 199.47 THz. The heterodyne technique for terahertz and gigahertz frequencies in these designs is very promising. The generated frequency is 0.125 THz, this suggests that the proposed design can be used for beat frequency generation and multi-sensing application.