Ultrahigh-resolution interrogation of a fiber Bragg grating sensor based on higher order four-wave mixing

The performance of a highly sensitive strain sensor based on nonlinear four-wave mixing (FWM) using a fiber Bragg grating (FBG) is investigated. The power change due to the wavelength shift induced by very small strain over the FBG is significantly magnified by a higher order FWM process. Strain sensitivity of 5.547 dBm/pr is achieved and minimum wavelength shift of 2.18 x 10(-5) nm (which corresponds to a strain of 1.80 x 10(-3) mu epsilon) is detected with uniform FBG, whereas in case of chirped FBG (CFBG) strain sensitivity of 0.3 dBm/Fie with minimum detectable wavelength shift of 4 x 10(-5) nm (which corresponds to a strain of 0.033 mu epsilon) is obtained. (C) 2018 Optical Society of America.