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Optimization Design And Experiment Research Of High Power Optical Fiber Amplifier

Posted on:2012-03-10Degree:MasterType:Thesis
Country:ChinaCandidate:X G LiFull Text:PDF
GTID:2178330332499597Subject:Communication and Information System
Abstract/Summary:PDF Full Text Request
The capacity of communications business is increasing explosively. The development of large capacity, long-distance DWDM trunk transmission technology and increasingly complicated optical network topology need optical amplifiers of high saturated output power. On the basis of the doped Er3+ ions, Er/Yb co-doped double-clad fiber amplifier(EYDFA) incorporate a considerable proportion of Yb3+ ions. This can resolve the concentration quenching caused by high concentration of Er3+, inhibit self-pulsing and widen the absorption spectrum. In addition, based on double-clad fiber, the cladding pumping technology increases the pump absorption efficiency, and reduces the requirements of single-mode pump. With the high saturated output power in the optical communication wavelength of 1550nm, Er/Yb co-doped double-clad fiber amplifier can meet the growing power demand of the amplifier which is needed by fiber communications technology. So it has a broad application prospect.This paper gives the theory model and solution of Er/Yb co-doped double-clad fiber amplifier. On this basis, the parameters of amplifier are simulated and optimized by optical design software. On the result of optimization, the amplifier experimental system is established, and the performance of the amplifier is tested and analyzed. Under the condition of 10dBm signal power and 8A pump current, maximum output power of 30.29dBm(1.07W) is obtained. The works done in this paper are as follows:Firstly, the effect of Yb3+ ions as sensitizer and the advantage of double-clad fiber structure in the high power in Er/Yb co-doped double-clad fiber amplifier are expounded. The effect of different inner cladding shapes on pump coupling efficiency is introduced. The energy transfer relationship of Er/Yb co-doped system is analyzed, and hereby the theoretical model of amplifier based on rate equations and power propagation is given. The model is simplified according to the ion activity characteristics and the numerical solution of fourth-order Runge-Kutta method during steady-state is given. According to the results of the equations, the changes of amplifier gain with fiber length under the condition of different signal and pump power are also given. As the key technology of double-clad fiber amplifier, the clad pump coupling technology is introduced comprehensively.Secondly, based on the amplifier theoretical model of rate equations and power propagation, simulation and optimization of the amplifier parameters are made by optical design software. The amplifier simulation models in three different ways of forward, backward and bi-directional pumping are established, and their performance is compared and analyzed. The amplification characteristics under the condition of different signal and pump power are researched. The effect of the parameters such as active fiber length, doping concentration ratio of rare earth ions and cladding size etc. on amplifier output performance is analyzed. The amplifier of two-stage structure and pulse amplification are preliminary studied.Finally, according to the result of simulation and optimization on amplifier parameters, Er/Yb co-doped double-clad fiber amplifier with the forward pumping is established. The maximum output power of 30.29dBm(1.07W) is obtained under the condition of 10dBm signal power and 8A pump current. And the maximum amplified gain of 33.48dB is obtained under the condition of -10dBm signal power and also 8A pump current. The amplification characteristics to different power and wavelength of input signal light under the condition of different pump power are tested. And the effects of signal power, wavelength and pump power on amplification characteristics are analyzed. The causes of self-oscillation in amplification process and the relationship with signal and pump power are briefly introduced.Based on the theory analysis, this paper simulates, optimizes and experimentally researches the output performance of Er/Yb co-doped double-clad fiber amplifier. The trend between the experimental output and the optimization result is consistent. However, due to some differences between the simulation model and the actual amplifier, idealization of devices, the splicing loss, insertion loss and other factors existing in actual experimental, some gap between amplified output in experimental and the optimization result of amplifier still exist.
Keywords/Search Tags:Fiber Amplifier, Erbium-Ytterbium Co-doped, Double-clad, Output Performance
PDF Full Text Request
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