Gao R, Jiang Y, Jiang L
Opt Express. 2014 Jun 30;22(13):15697-709. doi: 10.1364/OE.22.015697.
A compact temperature-insensitive optical fiber twist sensor based on multi-phase-shifted helical long period fiber grating has been proposed and experimentally demonstrated in this paper. A multi-phase-shifted helical long period fiber grating is fabricated with a multi-period rotation technology. A π/2 and a 3π/2 phase shift is introduced in the helical long period fiber grating by changing the period. The helical pitch can be effectively changed with a different twist rate, which is measured by calculating the wavelength difference between two phase shift peaks. Although the wavelength of the phase shift peak also shifts with a change of the temperature, the wavelength difference between two phase shift peaks is constant due to two fixed phase shifts in the helical long period fiber grating, which is extremely insensitive to temperature change for the multi-phase-shifted helical long period fiber grating. The experimental results show that a sensitivity of up to 1.959 nm/(rad/m) is achieved.
本文提出并通过实验验证了一种基于多相移螺旋长周期光纤光栅的紧凑型温度不敏感光纤扭转传感器。采用多周期旋转技术制作了多相移螺旋长周期光纤光栅。通过改变周期，在螺旋长周期光纤光栅中引入了π/2和3π/2的相移。不同的扭转率可以有效地改变螺旋节距，通过计算两个相移峰之间的波长差来测量扭转率。虽然相移峰的波长也会随温度变化而移动，但由于螺旋长周期光纤光栅中有两个固定的相移，两个相移峰之间的波长差是恒定的，这使得多相移螺旋长周期光纤光栅对温度变化极其不敏感。实验结果表明，该传感器实现了高达1.959 nm/(rad/m)的灵敏度。
