一种基于LPFG高灵敏度浓度传感器

A higher sensitively concentration sensor using long-period fiber grating

利用Sagnac光纤环全反射的特性和单根长周期光纤光栅(LPFG)构成Michelson干涉仪,入射光经LPFG后,部分被耦合到包层中传输,经过包层和纤芯传输的光信号经Sagnac光纤环全反射后重新耦合回LPFG,在光栅区域干涉。利用传输矩阵理论分析了干涉结构的光谱特性。用此干涉结构检测了蔗糖溶液浓度,传感灵敏度可达0.065 nmLg-1。

A Michelson interferometer based on fiber ring and a LPFG is presented.The input signal is partly coupled into the cladding of the fiber by LPFG,both of the transmitted optical signals in the core and cladding are reflected by sagnac fiber ring and coupled simultaneously back to the LPFG and interfere.Spectrum characteristics are analyzed using transfer matrix method.The proposed device is experimented to serve a sucrose concentration sensor,whose sensitivity is measured to be 0.065 nmLg^-1.