Dynamic Probabilistic Shaping Technique Based On Intensity Modulation Direct Detection System

With the rapid development of science and technology,we use the Internet more and more popular,a variety of applications are born,such as cloud computing,artificial intelligence,smart home,virtual reality,unmanned driving,etc.,the development and application of these technologies are inseparable from big data and data traffic.This is a big data era,various new bandwidth service development,leading to increased data capacity into explosive growth year by year,in data communication,long-distance communication and short distance communication in the system of the large capacity data communication needs more and more big,this gives the current optical fiber communication system has brought great pressure and challenge.According to the forecast of Cisco Global Cloud Index,the annual global data center traffic will grow to20.6ZB by the end of 2021.In order to solve this problem,improve data communication capacity of optical fiber communication system especially in short distance communication has become a hot research topic in the field of optical communication in recent years,intensity modulation direct detection system is the present within the data center,data center,access network,such as short distance communication can be accepted in the field of optimal solution,a low complexity,high reliability,low cost and other advantages.The probabilistic shaping technology is a new coding modulation technology born in recent years.The research on probabilistic shaping has become a hot spot.The probabilistic shaping technology is mainly used to improve the channel capacity limit of the system and improve the error performance of the system.Probability shaping technology is mainly to change the probability distribution of the symbols in the signal constellation diagram.The signal with equal probability distribution is integrated into an unequal probability signal according to the Gaussian probability distribution model,increasing the probability of low power symbols,reducing the probability of high power symbols,and finally reducing the average transmitting power of the signal.Direct modulation is a maximum power(amplitude)limited system with no intermediate amplifier and no in-line dispersion compensation.The problem of increasing the channel capacity in the power limited direct modulation system becomes the problem of the size distribution of the signal space at a given bandwidth and maximum power(amplitude),and how to achieve it.Traditional PS according to the average power to realize the gaussian distribution,without consideration of problems,such as maximum power DPS technology and considering the direct straightening in bandwidth limited amplitude detection system,considering the maximum power(amplitude)of signal adjustment of dynamic probability distribution has the best input distribution,reduce the signal peak power,avoided due to high peak power input signal of the nonlinear disturbance.The main research contents and results of this paper are as follows:(1)The first system of intensity modulation direct detection system are analyzed and the related principle of probability plastic technology,the traditional intensity modulation direct detection system structure and signal modulation formats a careful discussion and analysis,and the intensity modulation direct detection system in nonlinear system has made the detailed analysis,this paper introduces the traditional probability plastic technology in straight straightening system shortcomings and the insufficiency.(2)It was proposed based on direct straightening cosmetic inspection system dynamic probability algorithm,and compared with the probability of static plastic analysis,and simulation software MATLAB to complete the test,the results show that compared with the uniform distribution of signals and ordinary static probability of plastic,plastic dynamic probability can bring 0.9 d B the channel capacity of ascension.(3)The design of dynamic probabilistic shaping system based on PAM4 and PAM8 signals is proposed and realized,and the simulation software is used to realize it.The simulation results show that DPS-PAM4 and DPS-PAM8 based on dynamic probabilistic shaping can improve the error performance of 0.8 d B and 1 d B respectively.(4)Discussed and studied based on the nonlinear damage probability of the plastic PSA suppression research,analyzes the research prospect and significance of PSA and PSA in the face of nonlinear damage,put forward probability plastic technology is introduced into the PSA to ease and nonlinear damage suppression system,and 16 QAM signals are simulated by using MATLAB software to design,the simulation results show that the PSA system based on probability of plastic brings about the EVM entry gain of about 3 d B.