To reduce the dispersion of optical signals in optical fibers and improve the output performance of the system,a cascaded fiber Bragg grating (FBG) structure is proposed in this paper.Firstly,three compensation schemes (pre-compensation,post-compensation,symmetric compensation) for dispersion compensation fiber (DCF) are analyzed,and it is concluded that the post-compensation scheme offers the optimal system performance.Next,the impact of post-compensation under different dispersion compensation methods on the system is analyzed.Subsequently,focusing on the post-compensation scheme,an FBG is cascaded after its transmitter to achieve a narrow optical signal linewidth and minimize the reflectivity side lobes,thereby reducing propagation delay and improving system performance.In both cases,with and without cascaded FBG,the influence of input power and transmission distance on the system is analyzed.The results show that with the DCF post-compensation scheme and the cascaded FBG,the transmission distance reaches 240 km,and the optimal input power is 21 dBm,resulting in an increase in the Q value from 37.152 75 to 60.552 1,representing a 63% improvement in system performance.This confirms that cascading FBG in the system can enhance the overall output performance of the system.This structure provides a solid foundation for future high-capacity,long-distance optical fiber transmission and holds promising development prospects.