Dynamic sensors based on fiber-ring laser using a semiconductor optical amplifier

Abstract

In this paper, we theoretically and experimentally demonstrate a dynamic strain sensor system utilizing a semiconductor optical amplifier (SOA)-based fiber-ring laser(FRL).The outside of the laser cavity consisting of a fiber FabryPerot(FFP) filter as an intensity demodulator. The SOA-based FRL is incorporating the fiber Bragg gratings(FBGs) as wavelength selective components for fiber lasers.The optical signals reflected from the FBGs are detected by photodetectors (PDs) after filtering by the FFP filter and band-pass filter (BPF). The change of the external dynamic strain will cause the spectral-shift of the reflected light of the FBG which can be dynamically monitored by the change of the output light intensity from the filter.The experimental results show that the sensing system we proposed here has a good response to the dynamic strain signal.In the meantime,we also simulated the spectra of the FFP filter and the FBG,and then we obtained the optimal response range near the peak of the spectrum of the FFP filter.The system demonstrated here has a simple structure and low cost,which make it attractive for dynamic strain detection in structure health monitoring.