,Curvature Sensor Based on a Long-Period Grating in a Fiber Ring Resonator Interrogated by an OTDR

• 作 者: Regina MAGALH(A)ES Susana SILVA Orlando FRAZ(A)O
• 机 构: INESC TEC and Department of Physics and Astronomy,Faculty of Sciences of University of Porto,Porto 4
• 出 处: 光子传感器（英文版）
• 发表日期: 2020年1期
• 关键词: Cavity ring-down curvature fiber ring resonator long period grating optical fibe

The proposed technique demonstrates a fiber ring resonator interrogated by an optical time domain reflectometer(OTDR),for intensity sensing.By using this methodology,a cavity round trip time of 2.85μs was obtained.For a proof of concept,a long-period grating was inserted in the resonant cavity operating as a curvature sensing device.A novel signal processing approach was outlined,regarding to the logarithmic behavior of the OTDR.Through analyzing the experimental results,an increase in the measured sensitivities was obtained by increasing applied bending.With curvatures performed from 1.8 m-1 to 4.5 m-1,the sensitivity values ranged from 2.94 dB.km-1 to 5.15 dB.km-1.In its tu,the sensitivities obtained presented a linear behavior when studied as a function of the applied curvature,following a slope of 0.86× 10-3 dB.The advantages of applying this technique were also discussed,demonstrating two similar fiber rings multiplexed in a series of configurations.