Real-time. Fibre Breakpoint Detector Developed

It requires real-time measurement to detect the location of breakpoints when the high speed guided fiber is under test, so this paper proposes the use of real-time fiber break detector to detect guided fiber in little time and high precision. In this dissertation, it clarifies the weakness of traditional multiple detection on average and gives a variety of encoding method such as Biorthogonal Code, Simplex Code, Complementary Correlated Prometheus OrthoNormal Sequence and Golay Complementary Code to improve signal to noise ratio. Through analysis and comparison of a variety of coding method, We can get the fiber break location by using Golay complementary codes as detection signal and doing the relevant operation between the echo signal and Golay complementary code. This method can effectively improve signal to noise ratio and significantly shorten the measurement time without loss of resolution. In order to meet different requirements of precision measurement, Ultimately it provides a method of combining the single-pulse and Golay complementary code detection.Based on the fiber break detection principle, the design gives detailed hardware and software design of using LM3S615 control GP1 performing high-speed high-precision single-pulse detection and using FPGA performing Golay complementary code auto-correlation detection. Ultimately, the experimental prototype is developed. FPGA generates single pulse or Golay complementary coded pulse to drive high-power laser and the signal from optical receiver is processed. Signal delay detection and different roughness of fiber breakpoint detection is finished to prove that the accuracy of single pulse detection is up to 0.1 m and meet the real-time high-precision measurement requirements. Though different bit error rate simulation, adjustment of sampling window and fiber experiments, it proves the precision of the detection by Golay complementary code is lm and meet the real-time high-precision measurement requirements.