切趾超短FBG中心波长解调实验研究

为提高光纤光栅传感器的测量范围和可靠性,本文采用单缝衍射方法实现了栅区长度小于1.5 mm,3 dB带宽大于1 nm,反射谱边缘有效线性区大于0.6 nm的切趾超短光纤光栅。并用其作为传感单元,提出了一种利用超短光纤光栅线性区域的中心波长解调方法。为了充分利用其反射光谱左右两侧的线性区,采用双波长激光的互补解调方法,将波长解调范围扩展到2.4 nm。实验结果表明,光功率与中心波长之间的线性度达到0.992。将测量值与实际值进行比较,两者具有较好的一致性.该方法具有结构简单、功耗小,测量空间分辨率高等潜在优势。

Experimental study on wavelength demodulation of apodized ultra-short fiber grating

To improve the measurement range and reliability of fiber Bragg grating sensors,apodized ultra-short fiber grating was fabricated by single slit diffraction,its grating length is less than 1.5 mm,3 dB bandwidth is over 1.2 nm,and the edge linear region of the reflection spectrum is over 0.6 nm. Taking apodized ultra-short fiber grating as sensor unit,a central wavelength demodulation method based on linear region of the reflection spectrum is proposed. In order to make full use of the linear region on the two sides of reflection spectrum,the complementary demodulation method with dual-wavelength lasers is used to extend the wavelength demodulation range. The experimental results show that the linearity between optical power and the central wavelength is 0.992,and the dynamic demodulation range of the central wavelength is 2.4 nm. The measured values are in great agreement with the actual values. The method has the potential advantages of simple structure,low power consumption and high spatial resolution.