Fiber curvature sensor based on dual-wavelength erbium-doped fiber laser (DWEDFL) with gain competitive intensity difference demodulation

Abstract

A fiber laser curvature sensor based on dual-wavelength gain competitive intensity difference demodulation is proposed and experimentally demonstrated. Here a linear cavity dual-wavelength erbium-doped fiber laser (DWEDFL) is build with two filter components i.e. fiber Bragg gratings (FBG) with very close center wavelengths. Since the dual wavelengths are sharing the same gain medium erbium-doped fiber (EDF), gain competition mechanism is formed with sensitive feature to external measurand curvature. Besides, the curvature information is demodulated by subtracting the power of the dual wavelengths. Experimental results show a total sensitivity as high as -57.22 dB/m−1. Our scheme not only improves the measuring sensitivity, but also eliminates the effects of source power jitter and external disturbances for example temperature shift since they do almost the same impact on the dual wavelengths.