| At the moment of rapid development of information technology and efficiency,the optical transmission mode of signals replaces the transmission mode with its absolute advantage.The optical signal is not easy to be shielded,and it can carry a large amount of anti-interference and many other advantages,which promotes the rapid development of lightrelated technology.In the field of sensing and monitoring,optical information transmission also plays an irreplaceable role.For example,people can use photoacoustic spectroscopy to measure the content of trace gases.However,in the actual application process,many signals are very low in energy after being converted into light,which is difficult to be detected,which greatly limits the application and development of these technologies.In fiber-optic communication,EDFA is often used to solve the problem of light attenuation.It can be seen that the EDFA can be used to amplify the weak optical signal to a higher level to facilitate subsequent processing and use.This paper mainly focuses on the simulation and experimental research on the technical points and parameter matching problems in the practical application of optical amplification using EDFA.In practical engineering and project application,it is often necessary to build an EDFA system according to the actual situation,so that it can not only play its due amplification,but also meet the environmental requirements and make the cost performance the highest.Therefore,it is necessary to study some practical application problems such as the relationship between gain and noise characteristics and fiber length,fiber doping radius and doping concentration;pumping mode and its power and wavelength effects on gain,and so on.The specific research contents of this paper include:The optisystem was used to build the EDFA system under different pumping modes and conduct experiments.First,the effects of pumping mode and pump wavelength on EDFA gain and noise characteristics are explored.The variables are three different pumping modes,two pump wavelengths and the length of the fiber.It is thus determined that the use of the bidirectional 1480 nm gain effect near the input power of 10 mW is the highest while the noise is small.Analysis of experimental data revealed that there is an optimal fiber length for maximum gain.Next,the pump light power and the input light power were changed separately to investigate the effect of the two power changes on the optimum length of the fiber.The experimental results show that the input optical power does not affect the optimal length of the fiber,and the optimal fiber length will increase when the pump power increases.In general,the optimum length of the fiber is about 8-12 m.And when the maximum length of the fiber is exceeded within a certain range,the gain is reduced less.Then the influence of the doping concentration of the lanthanum fiber on the gain and the total length of the lanthanum fiber on the noise are further explored.The analysis results show that the gain increases first with the increase of the doping concentration of the lanthanum fiber,and then decreases after reaching an optimal value.The optimum erbium concentration range is about 9×1024/m3 to 1.2×1025/m3.The length of the fiber should not exceed 40 m,otherwise the noise figure will deteriorate sharply.At the end of the experiment,the saturated output power and output spectral characteristics under good parameters were explored.The design experiment compares it with the common EDFA in the laboratory.It is found that under the optimal parameters,the gain characteristics of the EDFA system designed in this paper are obviously better than the experimental EDFA.The small signal gain is increased by about 8dB while the gain is also higher under the same pumping conditions,which satisfies the requirements of practical applications.Finally,the experiment is summarized,and the system construction and attention points in the practical application of EDFA are summarized. |
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