为研究一种低成本、性能优良的甲烷传感器,设计了一种基于Cryptophane E的纤芯失配型甲烷传感器。采用光功率计测试涂覆不同长度Cryptophane E的纤芯失配型甲烷传感器对不同浓度甲烷气体的敏感特性,分别在纯氮气和12%甲烷混合气中测定最佳敏感区长度甲烷传感器光功率强度随入射角的变化曲线,并求出光功率强度差值随入射角变化关系曲线以确定最佳入射角。结果表明,纤芯失配型甲烷传感器最佳敏感区长度为3 mm,入射角θ=1°时,光功率强度差值最大,甲烷最低检出限为2.3%,增加甲烷浓度,光功率强度增强。

In order to develop a methane sensor with low-cost and excellent sensitive characteristics,a fiber-core mismatched type methane sensor based on Cryptophane E was designed. The sensitivity of the fiber-core mismatched methane sensor with different lengths of Cryptophane E coating to various concentration mixed methane gas was measured. Optical power versus injection angle for the methane sensor with the best sensitive coating length in pure nitrogen and 12% mixed methane gas were measured respectively. In order to find out the best injection angle,the difference of optical power in pure nitrogen and 12% mixed methane gas were calculated as well. Results showed that the best sensitive coating length is 3 mm,and the maximum optical power difference emerges when the injection angle is at θ=1°. The lowest detection limit of the fiber-core mismatched methane sensor is 2.3%. The optical power increases with the increasing of methane gas concentration.