Intensity-Modulated Fiber Bragg Grating Sensor System Employing Fiber Dispersion

A novel intensity-modulated fiber Bragg grating (FBG) sensor system employing fiber dispersion is presented. A RF signal is generated at a photodetector by two modulated optical signals reflected from a sensing and a reference FBG. Bragg wavelength shift of the sensing FBG changes intensity of the RF signal due to a fiber dispersion-induced phase change, with temperature effect being compensated automatically by the reference FBG. Strain measurement with a maximum sensitivity of -0.34 muV/muepsiv has been achieved.