High Speed and High Stability Fiber Bragg Grating Sensing System Based on Fast and Wideband Tunable REC-DFB Laser Array

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A novel fiber Bragg grating (FBG) sensing system with a core laser source comprising a high-density integrated distributed feedback (DFB) laser array based on the reconstruction-equivalent-chirp (REC) technique is presented and demonstrated. This study proposes a fast and wideband wavelength-swept laser (WSL) based on a DFB laser array. 24 lasers are monolithically integrated with an 8 × 3 matrix structure with a wavelength spacing of 2.1 nm. The REC technique is used to simplify the grating fabrication and enhance the precise control of the wavelength spacing. Furthermore, a high-speed FBG sensing system using field-programmable gate arrays (FPGA) is proposed and demonstrated, achieving stable high-speed sweeping with a wavelength coverage of 50.4 nm and a sweeping frequency of up to 5.85 kHz without mode hopping. The FBG sensing system has a solid-state design without moving parts, allowing real-time, high-speed, and stable monitoring of temperature, pressure, strain, and displacement. It maintains superior stability even under challenging vibration and shock environments. Additionally, the system is cost-effective and is anticipated to have diverse industrial applications.