Ultrafast FBG Interrogator Based on Time-Stretch Method

We demonstrate an experimental realization of the time-stretch configured fiber Bragg grating (FBG) interrogator with an ultrafast speed. The interrogator consists of a home-made ultrabroadband fiber laser, an FBG sensor array, and two dispersive elements (single mode fibers). A time-stretch method is employed to convert the wavelength shift of the FBG sensor array to time shift via the principle of wavelength-to-time mapping. It is theoretically and experimentally demonstrated that the wavelength-related time shift suffers no influence although the Bragg wavelength and bandwidth of the strained FBG might be different. The interrogator works in real time, so that a single-shot measurement without carrying out any averaging is feasible.