Detection of dynamic signals from fiber Bragg grating sensors based on two-wave mixing in saturable Er-doped fiber

High-speed wavelength interrogation technology for fiber Bragg grating (FBG) has attracted increasing attention in recent decades. Dynamic population gratings, formed in the rare-earth doped fibers, can be worked as adaptive beamsplitters in the adaptive interferometric detection configurations based on two-wave mixing (TWM). In combination the advantages of a semiconductor optical amplifier-based fiber ring laser (SOAFRL) sensors and fast response of dynamic population gratings demodulation in TWM system, in this work, we propose a demodulator for fiber Bragg grating (FBG) sensor using an interferometer based on transient two-wave mixing via dynamic population gratings in saturable Er-doped fiber (EDF). The proposed simple and robust configuration has an all-fiber design based on commercially available elements which makes it promising for applications in optical fiber ultrasonic sensors. Experimental results show that the SOAFRL is stable and can stably respond to dynamic signals with high frequencies.