Nonlinear fiber-optic strain sensor based on four-wave mixing in microstructured optical fiber

We demonstrate a nonlinear fiber-optic strain sensor, which uses the shifts of four-wave mixing Stokes and anti-Stokes peaks caused by the strain-induced changes in the structure and refractive index of a microstructured optical fiber. The sensor thus uses the inherent nonlinearity of the fiber and does not require any advanced postprocessing of the fiber. Strain sensitivity of ?0.23 pm?με is achieved experimentally and numerical simulations reveal that for the present fiber the sensitivity can be increased to ?4.46 pm?με by optimizing the pump wavelength and power.