针对现有光纤倏逝波传感器灵敏度不高、不易封装等问题，本文提出一种超长分段结构光纤倏逝波传感器。运用光束传播法(BPM)对分段和直形波导模型进行数值模拟，分析相同纤芯直径，不同结构和溶液浓度对传感器灵敏度的影响，通过化学腐蚀方法制备出不同结构参数的倏逝波传感器，并用不同浓度亚甲基蓝溶液对传感器的灵敏度特性进行实验验证。实验结果表明：在腐蚀深度不变的情况下，增加传感长度和采用分段结构可以有效的提高传感器的灵敏度和检出限，该传感器对亚甲基蓝的探测浓度可达到10^{-6 mol/L 量级，其灵敏度高，结构简单，易制备，成本低，在物质光谱检测方面有着潜在的应用。}

Since the existing optical fiber evanescent wave sensor sensitivity is not high, not easy to be encapsulated and other issues, the long segmented structure optic fiber sensor is proposed. The waveguide modes of the segmented structure and straight are simulated and analyzed by using Beam Propagation Method (BPM). The effect of the same core diameters, the different structures and the concentration of solution on the sensitivity of the sensors are investigated. The sensors of different structure parameters are fabricated with chemical corrosion method, and the sensitivity tested by using different concentrations of the methylene blue solution. The experimental results show that in the case of fixed corrosion depth, increasing the length of optical fiber sensing and segmented number can effectively improve the sensitivity and detection limit of the sensor, and the lowest concentration of the methylene blue solution can be detected up to the order of 10^{-6 mol/L. The sensor has the advantages of high sensitivity, simple structure, easy fabricated, low cost, which is suitable for materials spectrum measurements.}