The present invention is a type of fiber Bragg grating interrogation method that allows high frequency dynamic measurements. The method utilizes a broad band light source connected 10 Ihe sensing elements. Each sensing comprises of two wavelength matching fiber Bragg gratings, a coupler, and a photodiode. The fiber Bragg grating closest to the laser source attenuates the central wavelength in the transmission spectrum and thus the reflection spectrum of the second fiber Bragg gratings. Variations in the intensity of the second fiber Bragg grating is measured by the photodiode and can be calibrated to the desired measurands.