A novel demodulation scheme for high precision quasi-distributed sensing system based on chaotic fiber laser

A novel demodulation scheme for strain measurement is proposed and demonstrated for a high precision quasi-distributed sensing system based on chaotic fiber laser. Using a cross-correlation algorithm, strain sensing and precise locating can be simultaneously achieved based on the amplitude variation and time delay of a cross-correlation peak. The relationship between the correlation peaks and wavelength shift of weak FBGs induced by strain is theoretically and experimentally analyzed. Experimental results show the strain deviation of 14 μϵ, and the spatial resolution is up to 7 mm. Multi-point synchronous measurements has also been implemented.