Synchronous Interrogation of Multiple FBG Sensors Using Multi-wavelength Parallel Swept Light Source

In this paper, a multi-wavelength parallel swept light source (MWPSS) is proposed for fiber Bragg grating (FBG) interrogation. The MWPSS has two main parts: a multi-wavelength light source used as a seed source and a synchronous lightwave synthesized frequency sweeper (SLSFS). The multi-wavelength of the seed source is shifted with a constant frequency sweeping step synchronously every circulation in the SLSFS. There is a one-to-one correspondence between the swept range of the seed source and the central reflection wavelength of each FBG sensor. By interrogating the data of reflection intensity in time-domain to calculate the difference between the center wavelength of each sensing FBG and the reference FBG, 10.055 +/- 0.005pm/degrees C temperature sensitivity and 1.614 +/- 0.002pm/mu epsilon static strain sensitivity were obtained synchronously without cross-talk.