A fiber grating environmental sensing system is described that has the ability
to measure strain, vibration, humidity and water content. Fiber gratings are used
to measure axial strain to accomplish these goals. An approach is described that
uses matched fiber grating sensors and filters to allow for thermal compensation
greatly reducing one of the key performance issues facing these systems. The system
may be deployed in such applications as roadways and paved surfaces, bridges, buildings
and aircraft and spacecraft. Means are described to implement transducers optimized
for specific environmental measurements as well as means to demodulate the fiber
grating sensors.