Based On The Raman Amplifier And Pulse Code Combination Technology Of Brillouin Optical Time-domain Analysis System Research And Application

Brillouin optical time domain analysis (BOTDA) has been a subject of intenseresearch and industrial development, due to their capability of measuring strain andtemperature simultaneously over long distances, enabling many practical applicationsranging from civil and structural engineering to environmental monitoring andgeo-technical engineering.One challenge of BOTDA system is how to improve the sensing distance, spatialresolution and measurement resolution simultaneously, while reducing the measurementtime. This paper puts forward a combined technology of bi-directional Ramanamplification and optical pulse coding to solve this problem. To ensure the tail-endmeasurement resolution,we extend the sensing distance to75km, with2.5m spaceresolution and20με、1℃measurement resolution.Based on our experiment system, we develop the appropriate software whichallows automatic control of the entire system and provides a friendly interactiveinterface. Also, we investigate the decoding algorithm related to optical pulse codingand Lorentz fitting algorithm related to Brillouin frequency shift with a result ofshortening the measurement time.Meanwhile, considering the status quo of current market demand of BOTDA andno BOTDA products with independent intellectual property rights in our country, wedesign BOTDA prototype and supporting software according to our own technology. Atlast, we give a detailed description of key device used by the system.