Fast and High-Precision Shape Sensing Based on Dual-Comb Fiber Bragg Grating Array Demodulation

This paper presents an innovative and efficient shape-sensing approach for optical fiber Bragg grating (FBG) arrays, employing the dual-comb spectroscopy (DCS) technique for demodulation. This scheme harnesses the power of dual-comb asynchronous sampling technology, enabling us to achieve high spatial resolution and rapid demodulation for shape sensing. It accomplishes this by sampling and demodulating ultrashort laser pulse signals reflected from gratings positioned at various locations. Our approach utilizes a single-cavity dual-comb FBG demodulation system and an array of identical FBGs within a compact fiber-optic setup to facilitate shape reconstruction. In static shape measurements, we have achieved impressive results, including submillimeter endpoint precision and a resolution error of less than 1% over a distance range of 423 mm for sinusoidal and arc-shaped structures with continuously varying curvatures. Furthermore, our system demonstrates exceptional capabilities in dynamic shape measurements, capable of capturing rapid movements at a measurement rate exceeding 1 kHz. It maintains a millimeter-level resolving capability for dynamic shape variations. Overall, our proposed scheme significantly enhances shape sensing capabilities, offering improved speed and resolution. This advancement opens opportunities in various fields, including robotic control, human-machine interaction, and surgical navigation.