Performance Analysis Of Wavelength-mode Division Multiplex System Based On Few-mode Fiber

With the rapid development of data services,the integration speed of IP network is accelerating day by day,so the expansion of network is particularly important.The research shows that the capacity growth of WDM optical transmission slows down obviously,and the system experiment is close to the Shannon limit of nonlinear optical fiber transmission,which restricts the development of all-optical communication.The spatial mode dimension is introduced,and the mode division multiplexing technology based on SMF is considered as an important scheme to further improve the transmission capacity.The combination of WDM and MDM will become one of the key ways to break through the capacity bottleneck.Increasing the number of channels has always been the research focus of WDM.It is of great significance to study how to match the number of wavelengths and modes in different scenarios to play the best performance of the system.This thesis mainly analyzes the influence of the change of wavelength number and mode number on the performance of WDM system,and deeply studies the key device parameters and modulation mode.The simulation software vpitransmissionmaker is used to build a mixed multiplexing system with few channels,and the influence of key device parameters on the system performance is analyzed.Then,the multi-channel hybrid multiplexing system is improved and built on the basis of the system.By changing the number of wavelength or mode,the performance of the system is observed.At last,combined with the analysis of the few channel hybrid multiplexing system and the number of wavelengths and modes,under the same number of channels,a multi-channel hybrid multiplexing system with different number of modes or wavelengths is built to observe the influence of the system SNR and laser linewidth on the system performance.The simulation results show that under the condition of signal-to-noise ratio of 20 d B and transmitter output power of 0 d Bm,using two wavelengths and six modes,each mode carries 25Gbit/s data,and realizes the transmission of 300 Gbit/s 4QAM signal without relay for 10 km distance under the level of 10^-5.The simulation results of the multichannel hybrid multiplexing system show that,by using 186 channel transmission,each mode carries 25Gbit/s data,realizing the 10 km distance of the 25×186 Gbit/s 4QAM signal without relay transmission in the order of 10^-5 in the low-mode fiber,and the total transmission rate reaches 4.65 Tbit/s.The construction methods are respectively31 wavelengths 6 mode hybrid multiplexing system and 62 wavelengths 3 mode hybrid multiplexing system.Through the comparative analysis of the two systems,it can be concluded that the performance of 62 wavelength 3-mode hybrid multiplexing system is better when considering the anti-noise ability;and the 31 wavelength 6-mode hybrid multiplexing system is more suitable when considering the large linewidth tolerance of the laser.The above research results are of great value for how to choose the number of wavelength and mode when building a WDM system.