基于光纤传感的无源铁路防护门开关状态监测系统

铁路防护门作为防火及应急疏散安全保障设施在铁路隧道中大量设置。在长期运营中，防护门一旦异常开启，一方面将失去防护门的作用，另一方面将可能侵入铁路限界危及运营安全。设计的防护门开关监测系统利用光纤将激光引至监测现场，利用光传感头将门的开关状态转换为光路的通断状态。根据解调仪安置点和被测防护门的分布情况，提出了星型组网方案和单芯级联组网方案，实现了对解调仪的复用，可降低系统的复杂度和工程成本。单芯级联方案中，为了使更多的光功率耦合到传感监测链路的远端，对耦合器的功率分配进行了分析及优化。针对铁路防护门的应用场景，提出了提高系统可靠性和环境适应性的措施。

Railway protective door condition monitoring system based on fiber optical sensor

Massive railway protective doors have been installed in railway tunnels as fireproofing and emergency evacuation facilities. During long term service, once the protective door is opened abnormally, it will be ineffective. More importantly, it may invade railway clearance and threaten railway operation safety. A door switch state monitoring system based on fiber optical sensors has been realized in this paper. In this system laser is transmitted to the railway protective door by fiber. With the help of the sensor, open-close state of the door will be converted into on-off state of the optical path. According to the distribution of protective door from the interrogator, the star connection structure and single fiber cascade connection structure are proposed in this paper. These connection structures realize interrogator multiplexing, which could reduce system complexity and engineering cost. In the single fiber cascade scheme, power optimization is made. In view of the application scenario of railway protective doors, the measures to improve the system reliability and environmental adaptability are put forward.