Enhanced multiplexing capacity of low-coherence reflectometric sensors based on 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 to be interrogated twice from opposite directions. The bi-directional interrogation doubles the multiplexing capacity while maintaining the signal to noise ratio. The double interrogation scheme would allow the normal operation of the sensor array even when one end of the transmission fiber was broken, improving the reliability of the sensing system for large-scale structural monitoring.