Measurement Of Second-Order Dispersion Fluctuation Of Fiber Grating Based On Optical Phase Modulator

When we use FBG to filter the optical signal, we pay more attention to its optical power spectrum and less attention to its dispersion fluctuation. However, if the dispersion fluctuation of FBG is too large, it may lead to signal distortion, so it is very important to detect the dispersion fluctuation of FBG. In this paper, we choose the FBG with wavelength of 1550nm and reflectivity of 95%, and use the method of phase to amplitude conversion to detect the second-order dispersion fluctuation of FBG. In the temperature range of 23 degrees C - 33.6 degrees C, we have measured the optical power spectrum and the second-order dispersion fluctuation curve of the fiber grating, and analyzed the experimental results. Then we find that when the FBG with flat optical power spectrum but large dispersion fluctuation is used for filtering, the output signal will be distorted.