Parallel multiplexing and demodulation of fiber optic strain gauges

The use of fiber-optic strain gauges in realistic smart structures applications is contingent on the availability of a number of sensors embedded or adhered to the structure at a cost comparable to that of existing on-board diagnostic sensor systems. The most effective way of implementing such a sensor topology is to share the most expensive components of the system among many sensors. A cost-intensive component in a fiber-optic strain gauge system is the laser diode and its associated drive electronics. Parallel multiplexing allows many gauges to share a common source. Design and performance issues related to parallel multiplexed fiber Fabry-Perot strain gauge systems are discussed. A commercial four-channel parallel multiplexed strain gauge system is described.