基于相移光纤光栅的布拉格波长解调原理的分析

Theoretical analysis of Bragg wavelength demodulation based on phase-shift fiber grating

提出了一种基于相移光纤光栅(phase-sh ifted fiber grating)的布拉格波长解调技术,相移光纤光栅在反射谱阻带中能打开线宽极窄的一个或多个通透窗口,而且窗口位置随所加相移量的大小呈线性变化。实验中应用电流调谐相移量以实现布拉格波长的解调。选用最大波长偏移量为2 nm的相移光纤光栅进行调谐滤波,温度的测量范围可达到200℃,应变的测量范围可达到2000μs。实验表明利用相移光纤光栅进行布拉格波长解调,取得了预期的效果,为布拉格波长解调技术提出了新的思路。

The Bragg wavelength demodulation technology based on phase-shift fiber grating is proposed. One or more spectral windows with very narrow line-width can be opened by the phase-shift fiber grating in the reflectance spectrum stop-band, and the windows are moved with the variations of the phase shift linearly. In order to implement Bragg wavelength demodulation, the electric current tuning phase-shift technology was utilized in the experiment. The measurement temperature could reach 200℃ and the strain could reach 2000 με when the phaseshift fiber grating with maximal wavelength offset of 2 nm was used to do the tunable filtering. The experiment shows that the Bragg wavelength demodulation by the phase-shift fiber grating has reached the expected result. A new method is established to solve the demodulation of Bragg wavelength.