Research Of Thulium Doped Fiber Amplifier

The demand of the S-band optical amplification is rapidly increasing with the development of optical communication technology,particularly the rapid development of WDM/DWDM.The energy structure in Tm³⁺exist the transition which can meet the S-band and S+-band.Although the energy structure of thulium ions are very complex,thulium-doped fiber amplifier(TDFA) is the most important device for the S-band and S+-band optical amplification,and its research will be very significant for the further broadening the optical communication bandwidth.Thulium-doped fiber amplifiers have become new hot spot of optical fiber communication devices.In this paper,we mainly do some analysis,simulation and comparison about the semiconductor laser multi-core pigtail outputting light field intensity,as well as the outputting light field intensity distribution of LD multi-core pigtail single-lens and dual-lens coupled.We analyze thulium-doped fiber amplifier performance based on the rate equation and the transfer equation and do a lot of simulations.The major and innovational work is as follows:1.Overview the level structural features of elements of the thulium,introduce its spectral characteristics and the research status as well as the system structure of thulium-doped fiber amplifier.Based on those work,some summarize and comparisons about the comparison of pumping schemes of TDFA are did.2.Study the thulium-doped fiber amplifier pumping source laser outputting light field intensity distribution.The outputting light field intensity distribution of LD multi-core pigtail single-lens and dual-lens coupled are analyzed and simulated after those work.The results show that large transmission distance will not lead to outputting beam separation when use dual-lens to coupled.In the same prerequisite,outputting beam radius is much smaller than single-lens after the dual-lens coupled.Dual-lens coupling effect is much better than single-lens.3.Use the method of rate equation and transfer equation to analyze the pump scheme of thulium-doped fiber amplifier.Mathematical model of pump scheme of thulium-doped fiber amplifier is set up,the parameters is also discussed under this model.4.The fluoride glass and tellurite glass thulium-doped fiber amplifier output signal gain characteristics are simulated respectively.Influence of the thulium ion doping concentration,fiber length,pumping power is detail studide and analyzed.The results show that there is a kind of match relationship among those three parameters.When outputting signal gain is a constant,the higher doping concentration,the lower the pumping power is required under a certain length of fiber;the higher pumping power, the shorter fiber length is required under a certain doping concentration;the higher doping concentration,the shorter fiber length is required under a certain pumping power.