Research On Performance Of All Optical Wavelength Conversion System For High Speed OFDM Signal

With the rapid growth of Internet traffic,user demand being gradually expanding rapidly,which makes people put forward higher requirements on the capacity of optical communication and the function of the optical layer.In this way,researchers are seeking for higher speed,higher quality and larger capacity optical communication networks.All optical wavelength conversion(AOWC)is the key technology to achieve high level all-optical networks.In addition,to further increase the network efficiency and decrease the blocking probabilities,the all optical wavelength conversion(AOWC)is needed to avoid wavelength contention for dynamic optical path switching at the nodes.We focus on all optical wavelength conversion in high speed optical communication,and introduce the polarization multiplexed orthogonal frequency division multiplexing(PM-OFDM)signal to improve the spectrum utilization and system capacity.According to the different rates of the signal,the receiver adopts the direct-detection and the coherent-detection respectively.All optical wavelength conversion for high speed polarization multiplexing OFDM signal is realized based on the four wave mixing(FWM)effect in semiconductor optical amplifier(SOA).Based on the basic transport equation and carrier rate equation in SOA,the high-speed PM-OFDM signal can be received without crosstalk.In this paper,the all-optical wavelength conversion system based on FWM effect is studied theoretically and simulated from the SOA parameters.The main innovations achieved are as follows:(1)Based on the theoretical model of four wave mixing in SOA,the basic transport equation and carrier rate equation of SOA are analyzed.Furthermore,the system performance for high speed polarization multiplexing orthogonal frequency division multiplexing(PM-OFDM)signal is studied from SOA parameters.The SOA parameters such as the gain saturation,the optical confinement factor and the carrier concentration are related to the wavelength conversion efficiency.(2)Based on the theoretical analysis in(1),the Photonics simulation software(VPI)is used to realize all-optical wavelength conversion system.At the receiver,the direct detection technology is used to simulate the all-optical wavelength conversion system for the high-speed PM-OFDM signal based on the orthogonal and parallel dual-pump respectively.(3)At the receiver,the coherent detection technology is used to analyze and simulate the all optical wavelength conversion system for the high speed CO-OFDM signal.The factors affecting the system conversion efficiency are studied from the laser phase noise and SOA injection current.