Abstract:The detailed corresponding relationship of chirped refractive index modulation coefficient,initial refractive index modulation and grating period's chirp coefficient were deduced by using coupled-mode theory,and both the numerical simulation investigation and experimental results were also given.The conclusions are drawn as follows:the equivalent grating period's chirp coefficient is determined by both the chirped refractive index modulation coefficient c and initial reractive index modulation n_(eff).Both the equivalent grating period's chirp coefficient and grating period's chirp coeficient c_p act together to determine the dispersion compensation amount.By properly controlling the average refractive index modulation,we can fabricate different dispersion compensation amount fiber Bragg gratings by using the same phase mask.