Spectra power and bandwidth of fiber Bragg grating under influence of gradient strain

Qinpeng Liu,Zhen’An Jia,Haiwei Fu,Xueguang Qiao

doi:10.1007/s13320-016-0325-9

Abstract

The reflective spectrum power and the bandwidth of the fiber Bragg grating (FBG) under gradient strain are researched and experimentally demonstrated. The gradient strain is applied on the FBG, which can induce FBG bandwidth broadening, resulting in the variation of reflective power. Based on the coupled-mode theory and transfer matrix method, the segmental linear relationship between the gradient strain, the reflective power, and the bandwidth is simulated and analyzed, and the influence of the FBG length on the reflective spectrum is analyzed. In the experiment, the strict gradient stain device is designed; the experimental results indicate that the reflective optic power and the bandwidth of the FBG under gradient stain are concerned with the length of the FBG. Experimental results are well consistent with the theoretical analysis, which have important guiding significance in the FBG dynamic sensing.

Highlights

As an important wavelength sensitive device, a fiber Bragg grating (FBG) has been widely studied and applied [1,2,3,4,5]
Most of the researches focus on the wavelength sensing technology and theory, but when the inhomogeneous field applying on the FBG, such as the gradient stain and gradient temperature, acts on the grating range of the FBG, which can lead to the FBG chirping, and the reflective spectrum shows new features, such as reflective power and reflective bandwidth [6,7,8,9,10]
The results show that the linearly chirped fiber Bragg gratings can broaden the bandwidth

Summary

Introduction

As an important wavelength sensitive device, a fiber Bragg grating (FBG) has been widely studied and applied [1,2,3,4,5]. Most of the researches focus on the wavelength sensing technology and theory, but when the inhomogeneous field applying on the FBG, such as the gradient stain and gradient temperature, acts on the grating range of the FBG, which can lead to the FBG chirping, and the reflective spectrum shows new features, such as reflective power and reflective bandwidth [6,7,8,9,10]. Photonic Sensors complete discussion of reflective spectrum power and the bandwidth for the whole range, which is not the accurate response relationship between the bandwidth broadening and the reflective optic spectra power (ROSP), and the relationship between them is necessary to further research, which is a precondition to the FBG wavelength and intensity sensing. The gradient-strain device is designed; the experimental results show a good agreement with the theoretical analysis, which is an important basis for designing an intensity modulation sensor for the dynamic and static measurement

Theory and analysis

Experiments

Conclusions