Long Period Grating Imprinted on a Flat-Shaped Plastic Optical Fiber for Refractive Index Sensing  

作　　者：Yuan LIU Yanfei ZHOU Haiyang BAO Jie ZHENG 

机构地区：[1]State Key Laboratory of Integrated Optoelectronics,College of Electronic Science and Engineering,Jilin University,Changchun 130012,China [2]Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130012,China

出　　处：《Photonic Sensors》2023年第4期39-49,共11页光子传感器（英文版）

摘　　要：A corrugated surface long period grating(LPG)was fabricated on a flat-shaped plastic optical fiber(POF)as a refractive index(RI)sensor by a simple pressing with the heat pressure and mechanical die press print method.The light propagation characteristics of an LPG imprinted on a multi-mode POF were analyzed by the method of geometrical optics.Theoretical and experimental results showed that the structural parameters of the sensor affected the RI sensing performance,and the sensor with a thinner flat thickness,a deeper groove depth of the corrugated surface LPG,and a longer LPG exhibited better RI sensing performance.When the POF with a diameter of 1 mm was pressed with the heat pressure to a flat shape with a thickness of 600μm,an LPG with a period of 300μm,a groove depth of 200μm,and a length of 6 cm was fabricated on it,and the RI sensitivity of 1447%/RIU was obtained with a resolution of 5.494×10^(−6) RIU.In addition,the influences of the POF cladding,tilting of LPG,and bending of the sensing structure were investigated.The results demonstrated that after removing the cladding and tilting or bending the LPG,the RI sensing performance was improved.When the LPG imprinted on the flat-shaped POF was bent with a curvature radius of 6/πcm,the highest sensitivity of 6563%/RIU was achieved with a resolution of 2.487×10^(−9) RIU in the RI range of 1.3330–1.4230.The proposed sensor is a low-cost solution for RI measurement with the features of easy fabrication,high sensitivity,and intensity modulation at the visible wavelengths.

关 键 词：Plastic optical fiber fiber optic sensor flat-shaped optical fiber long period grating refractive index sensing 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]