Del Villar Ignacio, Partridge Matthew, Rodriguez Wenceslao Eduardo, Fuentes Omar, Socorro Abian Bentor, Diaz Silvia, Corres Jesus Maria, James Stephen Wayne, Tatam Ralph Peter
Department of Electrical and Electronic Engineering, Public University of Navarra, 31006 Pamplona, Spain.
Institute of Smart Cities, Public University of Navarra, 31006 Pamplona, Spain.
Sensors (Basel). 2017 Sep 13;17(9):2094. doi: 10.3390/s17092094.
The diameter of long-period fiber gratings (LPFGs) fabricated in optical fibers with a low cutoff wavelength was be reduced by hydrofluoric acid etching, enhancing the sensitivity to refractive index by more than a factor of 3, to 2611 nm/refractive index unit in the range from 1.333 to 1.4278. The grating period selected for the LPFGs allowed access to the dispersion turning point at wavelengths close to the visible range of the optical spectrum, where optical equipment is less expensive. As an example of an application, a pH sensor based on the deposition of a polymeric coating was analyzed in two situations: with an LPFG without diameter reduction and with an LPFG with diameter reduction. Again, a sensitivity increase of a factor of near 3 was obtained, demonstrating the ability of this method to enhance the sensitivity of thin-film-coated LPFG chemical sensors.
通过氢氟酸蚀刻，可减小在具有低截止波长的光纤中制造的长周期光纤光栅（LPFG）的直径，从而将其对折射率的灵敏度提高3倍以上，在1.333至1.4278的范围内达到2611 nm/折射率单位。为LPFG选择的光栅周期使得能够在接近光谱可见范围的波长处进入色散转折点，在该范围内光学设备成本较低。作为一个应用示例，分析了基于聚合物涂层沉积的pH传感器在两种情况下的性能：一种是未减小直径的LPFG，另一种是减小了直径的LPFG。同样，灵敏度提高了近3倍，证明了该方法提高薄膜涂层LPFG化学传感器灵敏度的能力。
