Intrinsic microbend fiber optic sensors

In this paper, special optical fibers are embedded into 3-D braided carbon/epoxy composites to constitute intrinsic microbend fiber optic sensors for internal strain measurement. Samples with embedded optical fibers are braided through four-step method and processed through Resin Transfer Molding (RTM) process. Special measures are taken to prevent damage of the sensors. The microbend optic fiber sensor works well in a three-point bending experiment. The experiments show that the output intensity of the microbend sensor is proportional to the internal strain of the sample while the load increases. Similar results can be achieved as the load decreases. The results show that the embedded microbend fiber optic sensor is fit for internal strain measurement in 3-D braided composites.