针对布里渊光时域分析仪(BOTDA)的测试光路在长期使用中易发生故障进而导致BOTDA测试中断的问题, 设计了一种基于光时域反射(OTDR)原理的光路自动切换保护系统。系统以K60控制器为控制核心, 应用FLEXBUS接口挂载SRAM、FPGA和W5300, 集成K60+FPGA架构的OTDR模块, 通过光开关实现光路切换, 监测各个光路的故障情况, 能够在BOTDA测试光路出现故障时切换光路并发送短信报警；介绍了系统原理、主要硬件模块、以太网引导升级和光路自动切换保护软件流程。实验结果表明: OTDR动态范围达到35 dB以上, 满足BOTDA测试光路的监测要求。

In view of the problem that the testing optical path of the Brillouin optical time domain analyzer(BOTDA) is prone to failure in long-term use, which leads to the interruption of BOTDA testing, an optical path automatic switching protection system based on the principle of optical time domain reflectometer(OTDR) is designed. The system takes K60 controller as the control core, uses the FLEXBUS interface to mount SRAM, FPGA and W5300, integrates the OTDR module of K60+FPGA architecture, realizes the optical path switching through the optical switch, monitors the failure of each optical path, and can switch the optical path and send the short message alarm when the optical path fails in the BOTDA test; introduces the system principle, main hardware modules, ethernet guidance and upgrading and optical path self dynamic switch protection software process. The experimental results show that the OTDR dynamic range is more than 35 dB, which meets the monitoring requirements of BOTDA test optical path.