基于光纤腔衰荡光谱的浓度和温度测量

摘要

为了提高浓度和温度测量的灵敏度和稳定性,采用时域分析法监测光纤系统中的光损耗,研制了基于光纤环形腔衰荡光谱的传感系统.基于该系统对浓度和温度进行传感测量实验,分析了错位传感结构的参量选择,并研究了空载时腔内信号放大对脉冲强度和脉冲数量的影响.结果表明,当干涉长度L和错位量D分别为4cm和3.75μm时,干涉效果最优;脉冲强度是无腔内放大时的4倍且脉冲数量更多;当蔗糖和葡萄糖溶液浓度为0.100g/mL~0.400g/mL时,浓度灵敏度为756.51μs/(g/mL)和909.07μs/(g/mL),检测限为0.0014g/mL;当温度为30℃~200℃时,温度灵敏度为1.83μs/℃.该系统的设计和研究为浓度和温度的传感应用提供了有价值的指导.%In order to improve the sensitivity and stability of concentration and temperature measurement,the optical loss in the optical fiber system was monitored by means of time-domain analysis.A sensing system based on fiber loop ring-down spectroscopy(FLRDS)was proposed.Based on the measurement results of concentration and temperature,parameter selection of the core-offset sensing structure was analyzed experimentally.The effect of intra-cavity signal amplification on pulse intensity and pulse number was studied.The results show that,when the interference length L and offset D are 4cm and 3.75μm respectively,interference effect is optimal.Pulse peak intensity is 4 times that without intra-cavity amplification and pulse number is bigger.When the sucrose and glucose concentration is 0.100g/mL~0.400g/mL,concentration sensitivities are 756.51μs/(g/mL)and 909.07μs/(g/mL),and the detection limit is 0.0014g/mL.The temperature sensitivity is 1.83μs/℃ in the range of 30℃~200℃.The design and research of this system provide valuable guidance for sensing application of concentration and temperature.