Range extension method for reflective-matched FBG interrogation based on CFBG sensor

The reflective-matched FBG is an interrogation method that can realize automatic temperature compensation but has the disadvantage of a small measurement range. A range extension method is proposed to extend the measurement range of the reflective-matched FBG based interrogation system, extending the measurement range while the sensitivity of the system does not change significantly. In the experiment, we study the performance of the system composed of sensors and filters with different bandwidths, the maximum strain sensitivity of the system is 0.261 mV/mu epsilon, the sensitivity can still be maintained at 0.248 mV/mu epsilon after range extension. The tem-perature compensation capability of the system is also confirmed in temperature experiments, temperature ef-fects reduced to 7.8 % of the uncompensated system.