Sensor Multiplexing Based on a Finite-Impulse Response Lattice of Unbalanced Interferometers

A new approach for multiplexing interferometric fiber optic sensors is described and studied. The approach is based on a lattice of unbalanced Mach-Zehnder interferometers. This configuration is inherently low-loss and can be implemented and deployed in a simple manner. The signals from the cascaded sensors are extracted from the measured data via a layer peeling algorithm. A fifth-order polarimetric implementation of the proposed multiplexing technique has been constructed and characterized. The third sensor was buried in a sandbox while the rest of the sensors were spooled on a bobbin. The system successfully separated and monitored the pressure variations in the different sensors with minor crosstalk.