Fast Interrogation of Single-Fiber Integrated FBG-FP Sensors Based on Programmable Spectrum Acquisitions

In situ dynamic/static mixed multiparameter measurement plays an important role in the condition monitoring of large equipment such as aero-engines and power transformers. For quasi-static multiparameter measurement, simultaneous demodulation of fiber Bragg grating (FBG) sensors and Fabry-Perot (FP) interferometric sensors can be achieved through full spectrum analysis. However, for measurements involving dynamic interferometers, existing solutions are mostly a combination of multiple independent systems. Herein, we propose a novel programmable spectrum acquisition and demodulation technique aimed at fast interrogation of single-fiber integrated FBG-FP sensors. Through programmable optical frequency sampling, the full spectrum covering 191.316-196.315 THz is collected while performing frequency-modulated phase shifting interferometry (PSI). This scheme realizes fast phase demodulation (100 kHz) of the FP vibration sensor and spectrum demodulation (20 Hz) of the FBG temperature sensor, which provides an attractive solution for in situ dynamic/static multiparameter measurement and system miniaturization.