| Accelerate the national strategy for marine power propulsion proposed the urgent demand to the seabed monitoring network,long distance optical transmission problem of large-scale remote sensing network of optical fiber is the key to restrict the size of the network,to further increase the transmission distance for reducing the number of relays,reduces the sea submarine engineering cost and has important significance to improve the system reliability,determine the monitoring technology of submarine network really to practical application.Forward distributed Raman amplifiers can effectively compensate for long distance transmission loss,which provides an attractive prospect in increasing the transmission distance.However,the increase of the DFRA gain causes the rapid enhancement of the modulation instability effect in the fiber,which leads to the sharp deterioration of the phase noise of the interferometric fiber optic sensing system,which is offset by the benefits brought by the introduction of the DFRA distributed gain.Study on interferometric distance transmission system to the Raman pump on MI effect enhancement law,its influence on phase noise,and to fully tap the potential of DFRA technology for suppressing method has the feasibility of the project,to make full use of the existing infrastructure and basic technology has important significance to enhance the transmission distance Based on this background,this paper makes an experimental study on the mechanism of phase noise and the suppression of MI in the long distance optical transmission system.Based on the amplified spontaneous emission noise(Amplified Spontaneous,Emission,ASE)and the experimental study on the effect of DFRA on MI gain threshold,by reducing ASE noise suppression MI and experimental verification of the selected DFRA gain and pulse peak power control combined with a preliminary feasibility suppression of MI optical transmission system of the Department of a set of eight from the 100 km wavelength to test a large number of phase noise data,the background noise is-88 dB.Paper main research results are as follows:i.The linear stability of MI is analyzed by introducing the self-phase modulation and cross phase modulation,and the gain spectrum is simulated.ii.Aiming at the limitation of the MI threshold formula,the effects of ASE noise and DFRA gain on MI threshold has get a large number of experimental research,and obtained the ASE noise increases,the DFRA gain is higher and the lower the threshold of MI conclusion,it provides the experimental basis for the inhibition of MI.iii.A large number of experimental studies on the effect of MI on phase noise in remote transmission are carried out.The results show that the MI is more obvious,the phase noise is worse,and the transmission performance of the system is affected.This paper also uses ASE to reduce noise suppression of MI and optimize the system phase noise,phase noise and the decline of 3dB verified the selected appropriate Raman gain and pulse peak power control combined with the feasibility of the initial suppression of MI iv.A series of phase noise testing is carried out on the eight wavelength round trip 100km optical transmission system,and the final selection of the appropriate device and a good experimental environment is the background of the system phase noise in-88dB... |
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