Research On All-optical Format Conversion Technology With Wavelength Preserved

With the advancement of big data,cloud computing,5G and other technologies,there is a higher requirement for the capacity and transmission rate of existing communication networks.Optical communication networks have developed rapidly due to their high speed,large capacity,and good confidentiality.In the case of less and less channel bandwidth resources,in order to further meet this demand,high-order modulation format signals with high spectral efficiency have received widespread attention.In future optical networks,the signal modulation formats transmitted in them will be different for the different service requirements between different networks.Therefore,the format conversion between different networks has important research value.All-optical format conversion technology has important development potential because it completes the format conversion directly on the optical domain without the need for the"optical-electrical-optical" conversion process,which can fundamentally overcome the bottleneck limitation of "electronic rate".This paper makes in-depth research on all-optical format conversion of several common modulation formats with wavelength preserved,and proposes several all-optical format conversion schemes.The main work is as follows:1)All-optical format conversion for BPSK signals and star 8QAM signals.This paper uses a variety of non-linear effects such as phase-sensitive amplification,self-phase modulation,and cross-phase modulation to complete the format conversion between the BPSK signal and the star 8QAM signal.On the on hand,signal wavelength remains unchanged after conversion,On the other hand,no loss and no redundancy of the converted signal information.2)All-optical format conversion of BPSK signal and 16QAM signal.First,the coherent superposition technique is used three times to realize the format conversion of BPSK signal to 16QAM signal.In the scheme of converting the 16QAM signal back to the BPSK signal,the second-order phase quantization technology and the spectrum shifting device are used to realize the coherent superposition of the original signal and the conjugate harmonic to obtain two PAM4 signals.Then use degenerate four-wave mixing and coherent superposition to convert PAM4 signal to BPSK signal.Under the condition that the signal wavelength is unchanged after the conversion,this solution can recover the input four BPSK signals without distortion,so that the data can be sent to the corresponding receiver to complete the reception.