| Summary: | 碩士 === 淡江大學 === 電機工程學系碩士班 === 107 === In this thesis, we investigated the optical time-domain reflectometer-based smoke sensing technique, which employs the physical contact (PC) fiber end facet and the 8-degree angled physical contact (APC) fiber end facet as the smoke sensing probes and utilizes the optical time-domain reflectometer to measure their optical return losses. The sensing principle of the smoke sensing technique is to form a diffuse reflection or specular reflection on the end facet of the fiber by the smoke, which further changes the return loss value of the end facet of the smoke detector fiber.
The experimental results demonstrate the feasibility and effectiveness of the proposed smoke sensing technique of utilizing the optical time-domain reflectometer. After injecting 20-second smoke into the experimental bottle connected with an APC fiber connector, we obtain a significant 20-dB difference and extreme transient fluctuations in optical return loss during the smoke sensing. However, with the UPC fiber connector, we gain a better stable variation in the optical return loss. To avoid the occurrence of false alarms during the smoke sensing, UPC has better smoke sensing performance.
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