| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 95 === This thesis focuses on in-service WDM-PON monitoring and includes five Chapters. Chapter 1 is an overview and description of thesis structure. After introduce of the concept and key components/devices using in WDM-PON in Chapter 2, In Chapter 3, we take a conventional bidirectional WDM-PON configuration as an example to study. Then we analyze every monitoring parameter in such a system. We find that in the conventional experiment, we could trace which fiber branch is broken, but are unable to confirm where the precise broken distance is. Thus, we try to overcome this drawback by adding a ratio coupler and wavelength-tunable optical time domain reflector (OTDR). The monitoring signals SNR obtained in the central office (CO) is about 5 dB and power penalty is less than 0.2 dB during the monitoring period. In the following chapter, we introduce an optical path monitoring method in a WDM-PON configuration. In experiment 1, we use C/L band WDM pair to divide monitoring and transmission signals, the monitoring signals could be reflected to the CO by the help of an optical circulator (OC). A blind spot may arise in such configuration if the monitoring and transmission signals are not propagate in the same path. In experiment 2, we use a special OC, a C/L band WDM and a fiber mirror to solve this problem as mentioned in experiment 1. So, the monitoring and transmission signals are transmitted in the same path as predicted. In this modified architecture, a 2 2 optical switch (OSW) is used to select either the optical spectrum analyzer (OSA) and OTDR pair for monitoring the upstream or downstream signals. The configuration has the merit of cost effective. Finally, a brief conclusion and suggested future work will be given.
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