后向喇曼散射分布式光纤感温火灾报警系统稳定性的改进

Improvement of stability of Raman backscattering optical fiber temperature fire alarm system

对基于后向喇曼散射分布式光纤感温火灾报警系统工作不稳定的主要原因进行逐一分析,其中降低提取弱信号的喇曼散射光波分复用器的光路损耗为主要措施.恒温恒压使APD工作在增益-偏压曲线平缓段,以提高APD增益的稳定性.采用实时累加采集卡来提高时间分辨率.通过上述多种措施相结合,系统稳定性明显提高.

The parameters affecting the stability of Raman backscattering optical fiber temperature fire alarm system were analyzed, and methods to improve stability were applied. A new wavelength division multiplier （WDM） was used to extract the Raman scattering signal from a data fiber, which can reduce peak insertion loss and increase isolation significantly. Measures were taken to keep APD （avalanche photo diode） working at a constant temperature and at a low reverse voltage so as to maintain the avalanche multiplication at a constant gain. A special data acquisition card for Raman signal processing was adopted to improve time resolution The result shows that the stability of the system was improved with theapplication of these measures.