Enhanced multiplexing capacity of low-coherence reflectometric sensors with a loop topology

A novel scheme for enhancing the multiplexing capacity of low-coherence reflectometric sensors is demonstrated. The scheme is based on connecting the sensing elements in serial in a loop configuration, allowing each of the sensors within the array being interrogated twice from opposite directions. The bi-directional interrogation enhances the multiplexing capacity in terms of maximum sensor number. The bi-interrogation scheme would also allow normal operation of the sensor array even when one end or somewhere of the transmission fiber were broken, improving the reliability of the sensing system for large-scale structural monitoring.