Backend Algorithm Research Of Raman Amplifier Multiplexing OTDR

With the continuous optimization of raman amplifier's performance and transmission distance in long-haul and metropolitan optical networks,it has become a better choice for future ultra high speed communication system.In the early days,raman amplifier is widely believed to be challenging for its operation difficulty and complicated installation procedure.Employing raman amplifier multiplexing OTDR technique,which means combing OTDR detection circuit and intelligent monitoring software with exsiting raman amplifier bump light source to design a raman amplifier device with OTDR function.This technique can automatically preactivate raman amplifier installation test procedure,simplify engineering steps and collect optical fiber information for analysis.It can perfectly solve the problem in raman amplifier operation.The key part of intelligent monitoring software for raman amplifier multiplexing OTDR device is OTDR algorithm design.Different from normal laboratory OTDR testing optical lines,raman amplifier transmission line usually works in on-line mode,in which mode service signal and test signal transmits in the same optical line.Due to the service light,OTDR test trace induces noise signal and no accurate algorithm has been designed for on-line OTDR test until now.By in-depth analyses on raman amplifier multiplexing OTDR device on-line test signal model,it puts forward an entire optimization solution on OTDR algorithm design.The solution settles the following issues:(1)locating optical event and its loss for improving raman amplifier operation security;(2)in-time monitoring of optical fiber line performance for trouble shooting effectively;(3)automatic & high precision test result for decreasing maintenance cost.This thesis proposes application difficulty of raman amplifier and discusses the existing problems of all the OTDR algorithms;Bases the analysis of OTDR end locating,reflective event locating and non-reflective event locating on OTDR data modeling and discusses the key issues of the non-reflective detection optimization,and then proposes the method of doing a new algorithm including the difference conversion,houghtransformation,pattern recognition;Describes programming realization of the algorithm and gives a feasible algorithm comparision between the algorithm and the existing commercial OTDR.Analysis shows it gives a significant improvement of the detection accuracy from 80%(commercial OTDR)to 97%,which can satisfy the raman amplifier installation requirements in ultra high speed communication system.