A highly sensitive four-wave mixing-based microstructured fiber refractive index sensor for microfluid sensing applications

Abstract

A four-wave mixing (FWM)-based refractive index sensor for potential microfluid sensing applications was proposed and analyzed in theory and experiment. The RI sensitivity of 6238.90 nm/RIU was obtained with a highly nonlinear microstructured fiber shortened to 60 mm, and the RI sensing resolution is as high as 2.2 × 10-5 RIU. By choosing an appropriate wavelength domain, the signal wavelength for RI sensing is considerably more stable, and the sensing figure of merit is much higher than others. Finally, an inline FWM-based microfluid RI sensor with microslot structures constructed by femtosecond laser ablation was fabricated successfully.