Wang Zhiyong, Heflin J, Stolen Rogers, Ramachandran Siddharth
Opt Express. 2005 Apr 18;13(8):2808-13. doi: 10.1364/opex.13.002808.
We theoretically and experimentally demonstrated that the resonant wavelength of long period fiber gratings (LPG) could be shifted in a large magnitude by coating only nm-thick thin-film whose refractive index is higher than that of the glass cladding. The resonant wavelength shift results from either the variation of the thickness of the film and/or the variation of the refractive index of the film. These results demonstrate the sensitivity of LPG-based sensors could be enhanced by using a sensing thin film with an allowed large thickness and high refractive index. This coating schematic offers an efficient platform for achieving high-performance index-modulating fiber devices and high-performance index/thickness-sensing LPG-based fiber sensors for detecting optical property variations of the sensing thin-film coating.
我们通过理论和实验证明，仅通过涂覆厚度仅为纳米级、折射率高于玻璃包层的薄膜，长周期光纤光栅（LPG）的谐振波长就能发生大幅度偏移。谐振波长的偏移是由薄膜厚度的变化和/或薄膜折射率的变化引起的。这些结果表明，通过使用具有允许的大厚度和高折射率的传感薄膜，可以提高基于LPG的传感器的灵敏度。这种涂覆方案为实现高性能折射率调制光纤器件以及用于检测传感薄膜涂层光学性质变化的高性能折射率/厚度传感LPG基光纤传感器提供了一个有效的平台。
