包层腐蚀长周期光纤光栅对的光谱特性研究  

Spectral characterization of long-period grating pair with etched fiber-cladding

作　　者：丁金妃[1] 付宏燕[1] 

机构地区：[1]浙江大学现代光学仪器国家重点实验室光及电磁波研究中心

出　　处：《浙江大学学报（工学版）》2007年第3期537-540,共4页Journal of Zhejiang University：Engineering Science

基　　金：浙江省自然科学基金资助项目(R104154)

摘　　要：为了提高长周期光纤光栅(LPG)在折射率(RI)传感中的光谱质量和灵敏度,提出了一种包层腐蚀的LPG对结构.应用耦合模理论,分析了单个LPG的谐振波长和透射损耗峰值随光纤包层直径减小的变化特性.采用两个级联的透射率为3dB左右的LPG,构成了光纤光栅马赫-泽德(M-Z)干涉仪.实验中采用氢氟酸腐蚀的方法来减小光纤包层直径,观察了包层腐蚀的LPG对透射光谱的演变过程,并测量了不同腐蚀程度的LPG对的折射率响应特性.结果表明,透射光谱中的干涉条纹随着包层直径的减小向红波方向移动,且对应包层模的阶数越高波长移动越大.随着腐蚀程度的增大,LPG对用于外界折射率传感的灵敏度得到了显著的提高.To improve the spectra quality and sensitivity of a long-period grating （LPG） in refractive-index （RI） sensing, an LPG pair with etched fiber cladding was proposed. Based on the coupled mode theory, the spectral characteristics including the resonant wavelengths and the transmission loss peaks in a single LPG with the reduction of the fiber cladding diameter were analyzed. Two cascaded LPGs with transmissivity of 3 dB were adopted, and an in-fiber Mach-Zehnder （M-Z） interferometer was formed. The HF etching process was utilized to reduce the fiber cladding diameter in the experiment. The evolution of the transmission spectra with the etched LPG pair was observed, and the responses of the LPG pairs with different etching degrees were measured. The results show that the interference patterns of the transmission spectra experience red shifts with the reduction of cladding diameter. The red shifts for higher order cladding modes are larger and the sensitivity to the surrounding RI is obviously enhanced with the increasing etching degree.

关 键 词：长周期光纤光栅对 腐蚀处理 光纤传感器 折射率测量 

分 类 号：TN253[电子电信—物理电子学]