High Performance Time Domain FBG Dynamic Interrogation Scheme Based on Pulse Coding

A novel method to improve the measurement range, resolution, and multiplexing capability of time division multiplexed (TDM) fiber Bragg grating (FBM) sensors, based on advanced cyclic pulse coding, is proposed and experimentally demonstrated. The mechanism of noise reduction by quasi-periodic cyclic coding is quantitatively demonstrated, pointing out significant improvement in dynamic strain resolution with respect to single pulse TDM FBG interrogation. The use of cycling pulse coding allows for enhanced dynamic performance of real time strain measurement with respect to other coding techniques. The proposed technique can also enhance the sensing range of hybrid optical fiber sensor systems in which continuous static temperature/strain distributions and discrete dynamic strain in specific critical points are simultaneously measured over the same sensing fiber.