【摘要】 利用弱反射光栅低反射率的特性,提出了基于全同弱布拉格反射光栅的分布式光纤传感方案。采用"光波长时域反射"解调技术,进行定位和解调,实现高密集度的准分布式传感。从理论上分析了光纤光栅反射率、光栅单元间隔以及传输损耗等对传感系统复用容量的影响。结果表明,这种方法可以有效提高光栅传感系统的复用容量,并降低信号解调成本。实验验证了该方案的可行性,系统复用了4个反射率为6%的光纤布拉格光栅(FBG),实现了单点、多点测量,温度测量的分辨力达到0.12℃。更多还原

【Abstract】 By exploiting the low reflectivity of low-Bragg-reflective fiber grating,the distributed optical fiber sensing scheme based on identical-low-Bragg-reflective fiber gratings is proposed,theoretically analyzed and experimentally studied.The demodulation technology named "optical wavelength time-domain reflection",which utilizes the optical power variation of reflected sensing signal in both time domain and wavelength domain,is adopted.The influence of reflectivity of fiber grating,interval between adjacent gratings and transmission loss of delay fiber on the multiplexing capacity of the sensing system are also discussed.Results demonstrate that this sensing scheme can increase the multiplexing capacity of sensing system effectively,implement multi-point measurement and reduce the cost of signal demodulation.Experiments on this scheme are conducted to prove its feasibility.Four fiber Bragg gratings(FBG) with the reflectivity of 6% are multiplexed in this system,which agrees with the calculation result.The resolution of 0.12 ℃ for temperature measurement is obtained.更多还原