A high-speed FBG interrogation system based on DFB laser

Abstract

A novel high-speed fiber Bragg grating(FBG)interrogation system for static and dynamic measurement with a high-speed wavelength-swept laser is proposedIn this system,the high-speed wavelength-swept laser is a distributed feedback(DFB)laser which is driven by a 100 kHz sine wave and controlled by a 100 kHz square waveIn the range from 20 mA to 150 mA of the current drive signal,the DFB makes a 100 kHz frequency scan in the range of 1nm in spectrumBy combining with optical circulator,photodiode,the signal acquisition and processing part,the system has realized the static and dynamic signals measurementIn static temperature experiment,the linearity is 099921,and the accuracy is 8pmThe dynamic measurement of 2kHz and 4kHz vibrations is demonstrated with a measuring speed as fast as 100 kHzExperiments show that the system has a high precision and a good stability for dynamic signalWith a 100 kHz demodulation,we can give a 0-50 kHz frequency spectrum analysisThe results demonstrate that the fiber Bragg grating interrogation system is efficient and stableIt has competitive advantages in terms of simple structure,low cost,as well as the detection accuracy for highspeed FBG demodulation as fast as 100 kHz