费米折射率波导的包层吸收模谱特性和溶液浓度传感研究

采用0.004AgNO3-0.996NaNO3混合熔融盐,用离子交换技术在德国B270光学玻璃上制备了费米折射率分布渐变波导,理论分析了费米折射率分布渐变波导的包层吸收模谱特性.导波损耗测试实验验证了解析结果.在此基础上,提出了一种用于液体包层吸收损耗测试的双样品盒串连的波导回路.测试结果证实表征溶液包层吸收特征的折射率虚部与溶液浓度之间具有十分显著的线性关系,测试灵敏度与波导的模式和波导参量有关,尤其与波导层厚度有非常敏感的关联性.利用这个关系传感测试了13种不同浓度的耐晒果绿染料水溶液样品的浓度,结果显示测试值与实际配制浓度值的均方差小于0.07%.

Study on Clad Absorption Spectrum Characteristics and Solution Concentration Sensing using Fermi Refractive Index Waveguides

Fermi refractive-index distribution gradient waveguides are fabricated on the optical glass B270 using ion exchange process in the composite salt of 0.004AgNO3-0.996NaNO3. Absorption spectrum characteristics of the Fermi graded refractive index waveguide with an absorbent clad is theoretically analyzed. The experimental result about propagation loss of the waveguides is coincident with the analytic result. A testing waveguide circuit with a double-sample serial structure for measuring the liquid absorption loss is presented. The measured result shows that there is a remarkable linear relationship between solution concentration and refractive index's imaginary part which represents the feature of solution clad absorption, and the sensitivity is related to the modes and the parameters of waveguide, and particularly to the depth of waveguide. By using this sensing relationship, the concentrations C. I. Pigment Green7 solution samples 13 with kinds of different concentrations have been measured. The standard deviation between the measured values and the actual values is less than 0.07％.