基于纳米覆膜光纤F-P传感器的折射率光谱特性

采用层层组装和化学共价交联的方法对光纤Fabry-Perot (F-P)干涉传感器的端面进行了纳米聚电介质覆膜修饰，并实验研究了覆膜后传感器的折射率响应光谱特性。选择聚二甲基二烯丙基氯化铵(PDDA)和聚苯乙烯磺酸钠(PSS)为纳米覆膜材料，随着覆膜层数的增加，光纤F-P传感器的反射谱对比度呈现由高到低，再到高的规律，且反射谱对比度具有良好的温度稳定性。选取覆膜层数为20双层的光纤F-P传感器对一系列浓度的蔗糖和无机溶液进行了折射率光谱响应测试，实验测得折射率检测拐点由1.457延伸至1.4623，对低折射率物质的折射率灵敏度为24.53 dB·RI-1，对高折射率物质的折射率灵敏度为3.60 dB·RI-1，且均具有良好的线性。研究结果为光纤F-P传感器对低折射率物质的功能化检测提供了新方法。

Spectral Characteristics of Refractive Index Based on Nanocoated Optical Fiber F-P Sensor

An optical fiber Fabry-Perot (F-P) interferometer end surface was modified using layer-by-layer assembly and chemical covalent cross linking method, and the refractive index (RI) response characteristics of coated optical fiber F-P sensor were experimentally studied. Poly diallyldimethylammonium chloride (PDDA) and sodium polystyrene sulfonate (PSS) were chosen as nano-film materials. With the numbers of layers increasing, the reflection spectral contrast of optical fiber F-P sensor presents from high to low, then to high regularity. And the reflection spectral contrast has good temperature stability. The reflection spectra of the optical F-P sensor coated with 20 bilayers for a series of concentration of sucrose and inorganic solution were measured. Experimental results show that the inflection point extends from 1.457 to 1.462 3, and the reflection spectral contrast sensitivity to low RI material and high RI material is 24.53 and 3.60 dB·RI-1, respectively, with good linearity. The results demonstrate that the functional coated optical F-P sensor provides a new method for biology and chemical material test.