Research on Weak Signal Detecting in Distributed FBG Sensing System

The weak signal detecting and processing circuits are designed,which include pre-amplifier circuits with differential input and zero-measurand output,amplified fold adjustable second amplification circuits,low-pass filter,power conversion circuits,power supply protection and filtering,data acquisition circuits,etc. These circuits are simulated by Multisim and tested in experiment. The results from the simulation and experiments indicate that these detection circuits are able to detect nW grade light signal, having the excellent anti-interference performances and better linearity.