基于光栅结构的波长可控型海水折射率传感器

Wavelength-tunable seawater refractive index sensor based on grating structure

光纤型表面等离子体共振(SPR)传感器波长通常处于可见光波段,为使该类器件工作在光通信窗口,提出一种基于光栅结构的波长可控型海水折射率传感器,传感器传感区域由镀有光栅结构的侧边抛磨光纤构成。研究了传感区域横截面的电场强度分布、光栅不同结构参数与SPR传感器波长的关系以及在海水折射率范围内随着折射率变化共振波长的变化趋势,最后分析了共振波长与折射率两者的关系,得出该传感器灵敏度为5650 nm/RIU,分辨率可达到1.77×10^(-6) RIU,可实现快速、高灵敏度的海水折射率测量。

The wavelength of fiber surface plasmon resonance(SPR)sensor is usually in the visible light band.In order to make the device work in the optical communication window,a wavelength controllable seawater refractive index sensor based on grating structure is proposed.The sensing area of the sensor is composed of side polished fiber coated with grating structure.The electric field intensity distribution of the cross section of the sensing area,the relationship between different grating structure parameters and SPR sensor wavelength,and the change trend of resonance wavelength with the change of refractive index in the range of seawater refractive index are studied.Finally,the relationship between resonance wavelength and refractive index is analyzed.The sensitivity of the sensor is 5650 nm/RIU,and the resolution can reach 1.77×10^(-6) RIU,which can realize fast and high sensitivity measurement of seawater refractive index.