| With the advent of the digital age,people have higher requirements for transmission speed and communication capacity in communication systems.Optical fiber communication,as a long-distance,high-capacity,and high-speed communication method,stands out in modern communication.In the process of the development of optical fiber communication,the main factors limiting its progress towards longer distances,larger capacities,and higher speeds are fiber loss,dispersion,and nonlinear effects.Currently,with the invention of optical fiber amplifiers,the problem of transmission loss in optical fiber communication has been basically solved,and how to solve the dispersion and nonlinear effects in optical fiber communication has become a hot topic of research both at home and abroad.This paper conducts research on the dispersion problem in optical fiber communication,and the main research work and results of this paper are as follows:(1)Analyzing the reasons for dispersion,it is deduced that a narrow spectral line light source can reduce the impact of dispersion on optical fiber communication systems.The principle of dispersion compensation is explained,and the two most widely used dispersion compensation techniques,dispersion compensating fiber(DCF)and chirped fiber grating(CFBG),are introduced.(2)A fiber Bragg grating(FBG)cascaded model is proposed to obtain a narrow spectral width optical signal.The model consists of three FBGs cascaded together,and its structure and working principle are analyzed to demonstrate its ability to compress the spectral width of the optical signal.The Opti System software is used for simulation design,and the model is applied to single-channel and wavelength division multiplexing(WDM)communication systems to verify its effectiveness in improving system transmission performance.Although the cascaded model can compress the linewidth and reduce the impact of dispersion,it cannot completely eliminate dispersion,so verification of the model needs to be carried out in a communication system that has already used dispersion compensation technology.(3)A dispersion compensation scheme for cascaded fiber grating models in single channel communication systems is proposed.For single channel systems,two dispersion compensation schemes,DCF post compensation scheme and CFBG post compensation scheme,are used respectively.By comparing and analyzing the Q value at the same input power,it is concluded that the CFBG post compensation scheme is superior to the DCF post compensation scheme.A cascade model is added based on the use of the CFBG post compensation scheme.The cascade model is added in the following ways: pre,post,and symmetric placement.The three placement methods have the highest Q value improvement at an input power of 8d Bm,with 13%,18%,and 12% respectively.This confirms that adding a cascade model to a single channel communication system using a dispersion compensation scheme can improve the overall transmission quality of the system,and it is also obtained that the post placement of the cascade model is the best location for placing the cascade model.(4)A dispersion compensation scheme using fiber grating cascaded model in WDM communication systems is proposed.For four channel WDM systems,two compensation schemes,DCF and DCF+CFBG,are used respectively.By comparing and analyzing the Q value at the same power,it is concluded that the DCF+CFBG scheme is superior to the DCF scheme.Based on the use of DCF+CFBG wavelength division dispersion compensation schemes,a cascade model is added,with the addition methods of pre,post,and symmetric placement.After adding the cascade model,the optimal Q value of each channel in the WDM system has been increased by 4.2%,5.7%,and 3.4%,respectively.This confirms that adding a cascade model to a WDM communication system using a dispersion compensation scheme can improve the overall transmission quality of the system.At the same time,it is again verified that the post placement of the cascade model is the best location for placing the cascade model. |
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