中文摘要：

根据Beer-Lambert定律,设计了一种基于光纤环形衰荡腔的双环路气体浓度测量系统。通过加入掺Er光纤放大器（EDFA）的全光自动增益反馈环,对EDFA的增益进行控制,可使衰荡时间大大延长,提高了系统的测量精度。研究了EDFA产生的放大自发辐射（ASE）噪声对系统测量精度的影响,采用自适应滤波方法对实验数据进行处理.通过对比试验论证了自适应滤波方法对提高系统测量精度的作用。分析了光在不同浓度的CO气体中的吸收特性以及衰荡时间与气体浓度的关系。

英文摘要：

According to the law of Beer-Lambert,a new dual-loop gas concentration measurement system based on the fiber loop ring-down spectroscopy technology is proposed.The gain was controlled by adding an auto gain feedback loop of Erbium Doped Fiber Amplifier（EDFA）,therefore,ring-down time is prolonged and measuring accuracy is improved.Influence of Amplified Spontaneous Emission（ASE）Noise of EDFA on measurement accuracy was studied.A method of dealing with experiment data using Adaptive Filter was bring forward.Through the contrast experiment,it is proved that the measurement accuracy has been improved by using the adaptive filtering method.The absorption characteristics in CO gas with different concentrations and the relationship between ring-down time and concentration are also analysed.All of which provided important reference for the high accuracy gas concentration measurement.