Intrinsic fiber optic Fabry-Perots (FP) adhered to the surface of a cantilever beam are used as strain sensors. Low coherent demodulation with a scanning Michelson interferometer and interfringe resolution techniques allow absolute interrupt-immune measurements of static longitudinal strains with a resolution of a few microstrains. Low reflecting FPs arranged either in parallel or in series can be multiplexed by giving them a difference in their lengths.