Analysis of a Fiber Bragg Grating Interrogated by an Ultrashort Laser Pulse as a Distributed Sensing Scheme

We provide a clear perspective on the distributed sensing scheme based on an ultrashort pulse propagating through a long weak FBG. The narrow laser source is modulated by electro-optic modulator(EOM) to generate an ultrashort pulse. However, it is expended in wavelength domain at the same time. Different applied strain on FBG at certain locations are worked as spot events to illustrate the reflected pulse response as example. The important factor, relative position of the initial center wavelengths of the laser source and the FBG, is analyzed for the first time. The simulation result has guiding significance for choosing the appropriate parameters of the input pulse and long FBG in sensing applications.