Simulation of Optical Microfiber Strain Sensors Based on Four-Wave Mixing

We investigate the performance of a microfiber strain sensor based on the nonlinear four-wave mixing process. This simple sensor of only an elliptical microfiber has considerable advantages, such as sensing directly by microfiber inherent nonlinearity in the telecommunication range and being compatible with the existing fiber network. Dispersion, nonlinearity, and strain effect are analyzed to find optimum sensing performance. The numerical simulations reveal that the strain can cause a marked wavelength shift of the signal wave. The wavelength shift range can be more than 74 nm within a reasonable strain range. To the ultimate strain range of 30 mε, the average strain sensitivity of 2.46 pm/με can be obtained when the pump wavelength is 1550 nm and the peak power is 100 W. In addition to the range of 5 mε, it could achieve 9.86 pm/με by optimizing the fiber size and highly birefringent characteristic. This strain sensor with high sensitivity, simple configuration, light, and portable performance has wide applications in mechanical detection and fault diagnosis and is of intensified interest for a great deal of wavelength selected devices in quantum information process.