Interrogation of multiple embedded fiber sensors in civil structures using radio telemetry

Various fiber sensor multiplexing techniques, e.g., frequency-, time-, and coherence-multiplexing, have been examined in an attempt to ascertain the method best suited for interrogation of multiple sensors scattered throughout a modern civil structure. Based on embedded fiber sensor results conducted at a multistory reinforced concrete structure, where more than eighty single-mode and multimode fiber optic sensors have been embedded into the structure, it has been determined that in many instances a radio telemetry method of interrogating the sensors is optimal. Many real-world factors influence the overall nature of the use of multiplexed fiber sensors in civil structures. In instances where intensity-modulating fiber sensors have been multiplexed onto a single transmit/receive fiber, radio telemeterized command and data acquisition from the fiber sensor 'network' may be achieved. The development of the interrogation of the multiplexed fiber optic sensors is described.