Sensitivity Enhancement of Fiber Accelerometer Based on Slow-Light Phase-Shifted Fiber Bragg Gratings in Single-Core and Multi-Core Fiber

We proposed a configuration for optimizing a fiber accelerometer using slow light in a phase-shifted fiber Bragg grating. The proposed scheme in a conventional Mach-Zehnder interferometer is experimentally demonstrated. The phase-shifted fiber Bragg grating was inscribed in a single-mode fiber with a group index of 3.19. By introducing slow light into the interferometer through the phase-shifted fiber Bragg grating, the sensitivity was enhanced by 1.72 times compared to the same condition without slow light. For better integration and stability of the accelerometer, the phase-shifted fiber Bragg grating was inscribed in the outer core of the multicore fiber using femtosecond laser point-by-point technology. The central core and outer core of the fiber formed a novel Mach-Zehnder interferometer for slow light wavelength. This study provides important implications for enhancing the sensitivity of fiber Bragg grating accelerometer phase demodulation.