Ultra Sensitive Nonlinear Fiber Optics-Based Refractive Index Sensor Using Degenerate Four Wave Mixing Technique in Photonic Crystal Fiber

By using degenerate four wave mixing (DFWM) analysis, we proposed a refractive index (RI) sensor in photonic crystal fiber. This novel nonlinear fiber optics-based RI sensor works on the basis of Stokes and anti-Stokes photons shift, through DFWM technique under the influence of fourth-order dispersion. Here, the frequency shift of generated photons, as a response to change in the analyte RI, is analyzed using an appropriately modified nonlinear Schrödinger equation. Sensitivity of the proposed sensor is well optimized by tuning the pump wavelength and the pump power. Finally, we achieve a maximum sensitivity of -10 200 nm/RIU for anti-Stokes shift and 56 200 nm/RIU for Stokes shift, respectively, with lattice pitch of 2.94- and 1.205-μm diameter of the airhole and 1.5-kW pump power at the pumping wavelength of 1064.7 nm, which proves it to be an advancement in the field of biomedical and chemical applications.