Flexible sensitivity-tuning strategy for extending the dynamic range of UWFBG-based fiber-optic accelerometers

In this Letter, a technique to enhance the dynamic range (DR) of fiber-optic accelerometers (FOAs) is proposed by incorporating an ultra-weak fiber Bragg grating (UWFBG) into the sensing fiber segment. Demodulation can be performed between any pair of UWFBGs, enabling the sensitivity of the FOA to be adjusted according to application-specific requirements. The detection capability of large-amplitude signals is strengthened through reduced sensitivity. Simultaneously, the capture of weak signals remains guaranteed with the entire sensitivity of FOA. A fiber-optic diaphragm accelerometer (FODA) was constructed for verification, achieving a 14.59 dB improvement in DR. The DR can be further enhanced by optimizing the segmentation of the sensing fiber, demonstrating excellent versatility and stability.