Novel gas sensor combined active fiber loop ring-down and dual wavelengths differential absorption method.
Novel gas sensor combined active fiber loop ring-down and dual wavelengths differential absorption method.
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DOI：
10.1364/oe.22.011244
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发表时间：
2014-05
期刊：
影响因子：
3.8
通讯作者：
Yanjie Zhao;Jun Chang;J. Ni;Qingpu Wang;Tong-yu Liu;Chang Wang;Pengpeng Wang;G. Lv;G. Peng
中科院分区：
文献类型：
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作者：
Yanjie Zhao;Jun Chang;J. Ni;Qingpu Wang;Tong-yu Liu;Chang Wang;Pengpeng Wang;G. Lv;G. Peng
提出了一种结合双波长差分吸收法的新型有源光纤环衰荡气体传感器。采用两个不同波长的分布反馈半导体激光器（DFB LD）。用一个波长被目标气体的吸收线覆盖的半导体激光器进行传感。另一个LD，其波长中心在吸收线之外，用于参考。通过对参考信号和传感信号求差，可以得到气体吸收损失。与传统的单波长法相比，该方法能有效地消除系统中腔损耗变化和光电器件漂移的影响。采用自动增益控制的掺铒光纤放大器（EDFA）补偿衰荡腔中的光损耗，增加了衰荡腔的往返行程，提高了气体检测的精度。采用两个光纤布拉格光栅作为滤波器滤除放大自发辐射（ASE）光谱噪声。用65 mm长的气室测量了不同浓度的乙炔校准样品，以评价参比的影响。结果表明，在腔体中引入一定的附加损耗（0 ~ 1.2dB）时，0.1%乙炔的相对误差小于± 0.4%，24小时内测量浓度的相对误差小于± 0.5%。
A novel active fiber loop ring-down gas sensor combined with dual wavelengths differential absorption method is proposed. Two Distributed Feedback Laser Diodes (DFB LDs) with different wavelengths are employed. One LD whose wavelength covered with the absorption line of target gas is used for sensing. Another LD whose wavelength is centered outside the absorption line is used for reference. The gas absorption loss can be obtained by differencing the reference signal and sensing signal. Compared with traditional method of one wavelength employed, it can eliminate the influence of the cavity loss variety and photoelectric device drift in the system efficiently. An Erbium Doped Fiber Amplifier (EDFA) with Automatic Gain Control (AGC) is used to compensate the loss of the light in the ring-down cavity, which will increase the cavity round trips and improve the precision of gas detection. And two fiber Bragg gratings (FBGs) are employed to get rid of amplified spontaneous emission (ASE) spectrum noise as filters. The calibrating ethyne samples of different concentrations are measured with a 65 mm long gas cell in order to evaluate the effect of reference. The results show the relative deviation is found to be less than ± 0.4% of 0.1% ethyne when a certain additional loss from 0 to 1.2dB is introduced to the cavity and the relative deviation of measured concentration is less than ± 0.5% over 24 hours.