Research On Multi-channel Phase Regeneration Of MPSK Signals Based On Phase Sensitive Amplification

With the rapid development of modern communication technology,the Internet communication business has exponential growth,and the demand for information transmission speed and communication capacity has also risen sharply.In order to achieve the purpose of large-capacity transmission,multilevel phase shift keying(MPSK)is favored by many people due to its advantages of high speed,high spectrum efficiency and high non-linearity resistance and has been invested extensive research.However,when the signal is transmitted in the optical fiber,it may be affected by a variety of factors such as dispersion,loss and nonlinear effect,so that the quality of the signal is sharply degraded.Forther more,for the more advanced modulation formats,noise is more susceptible to noise in the fiber link as the signal's Euclidean distance in the constellation becomes closer and noise immunity becomes weaker.Therfore,in order to ensure the quality of the signal transmission,the signal needs to be regenerated so that the degraded signal is restored.At the same time,considering the wavelength division multiplexing(WDM)system widely used in optical networks nowadays,since multiple light waves are transmitted in the system at the same time,the non-linear effect between channels is aggravated so that the signals of all the channels are nore easily affected by the bypass signal.Therefore,it is very important and necessary to study the multi-channel MPSK signal simultaneous regeneration technology.Phase sensitive amplifiers(PSA)have been widely studied for many years due to its inherently phase-sensitive compression and low-noise amplification.Particularly in the field og phase regeneration,various achievements have been made such as simultaneous regeneration of amplitude and phase,regeneration of MPSK signals,phase regenerations with lock-free.In recent years,due to the mature WDM technology,it is widely used in optical fiber communication network.PSA-based multi-wavelength simultaneous regeneration technology came into being under the call of the times.However,most of the current researches concentrate on binary phase shift keying(BPSK),and few researches focus on quadrature phase-shift keying(QPSK),eight phase-shift keying(8PSK)or event higher order modulation format.Therefore,based on the existing principle of phase sensitive amplification,this dissertation studies the simultaneous regeneration of multi-channel MPSK signals and simulates rgeneration of four QPSK signals.The experiment results are agree with the theoretical analysis.The main contents of this thesis are as follows:1.Doing extensive research on the field of the application of PSA technology in recent years as well as domestic and foreign research status of multi-wavelength simultaneous regeneration,analysis both the advantages and disadvantages of the researches.Starting from four-wave mixing(FWM),the principle of phase regeneration by PSA is introduced,and the key point of phase regeneration is analyzed based on MPSK signal.2.With the theoretical support of phase regeneration based on PSA,analysis the feasibility of simultaneous regeneration of multiple MPSK signals by using the "walk-away-effect" of optical fiber bidirectional transmission.Combined with the frequency diagram and the experimental setup,we introduce the setting of frequency interval,harmonic selection and multi-channel simultaneous regeneration in the specific regeneration process.3.Combined with the feasibility of the second step of simultaneous regeneration of multiple MPSK signals,the simulation experiment is carried out using the simultaneous generation of four QPSK signals with high nonlinear fiber(HNLF)as the medium.We analysis the experiment results from the constellation,bit error rate,multi-channel regeneration compared with single-channel regeneration,the selection of "m" value and other aspects.