Simultaneously Interrogation of Multi Fiber Bragg Grating Sensors by an AWG Based Demultiplexer

Multifiber Bragg grating (FBG) sensor arrays are being used in the health monitoring of aerospace structures and civil engineering works, as well as the environment monitoring. However, the field interrogations of multi FBG sensors are still a big challenge due to the lack of portable, robust, high performance multi sensor interrogation devices. We have found that by thermally scanning an arrayed waveguide gratings (AWG) based demultiplexer, a device deployed in the telecommunication networks, multi FBG sensors can be precisely monitored simultaneously. The measurement resolution of this technique can be better than one picometer (equivalent to 0.1degC for temperature sensing) and the measurement time can be as short as milliseconds. Owning to the small size and ruggedness of AWG, it is potentially feasible to fabricate an all solid (no moving parts), palm size, robust and high-resolution interrogator for multi FBG sensor applications