| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 94 === In this thesis, we concentrate on various types of real-time monitoring technologies for power-splitting passive optical networks (PSPONs) and wavelength division multiplexing passive optical networks (WDM-PONs). We propose and demonstrate two different kinds of monitoring schemes for PSPON in tree-topology structure.
Firstly, we achieve real-time fault monitoring by using fiber-Bragg-grating (FBG) and Erbium-doped-fiber- amplifier (EDFA) with remote pumping which provides 18 dB net-gain at -10 dBm input signal. Secondly, we set FBGs in front of optical-network-units (ONUs) to reflect the optical pulse emitting from optical time domain reflectometer (OTDR). Then these reflections will be regarded as survival signals in central office, and they still have 6 dB signal-to-noise floor-ratio. For WDM-PON issue, we design a basic monitoring model for AWG based PON firstly. This model causes 1 dB extra loss due to insert a 1310/1550 WDM coupler to signals. The side-mode-suppress-ratio (SMSR) of signals at ONU is above 40 dB. In the experiment of 2.5 Gb/s bit-error-rate (BER) testing, power penalty is only 0.3 dB.
Secondly, we propose three monitoring technologies based on optical switch (OSW) and WDM de-multiplexer. We can divide these technologies into time-sweeping mode and non-time-sweeping mode. The first scheme of time-sweeping mode can apply to any type of WDM-PONs. It causes 13 dB extra loss to signals and induces extra power penalty of 0.4 dB. The second scheme of time-sweeping mode is suitable AWG based PON only. It causes 7 dB extra loss to signals but just induces extra power penalty of 0.2 dB. Both of them have negligible deterioration to communication quality. Finally, we propose a non-time-sweeping mode monitoring scheme. Such scheme can apply to any type of WDM-PON. Although it might causes 10 dB extra loss to signals, it could increase the received power as much as 5 dB by utilizing 4% reflections at fiber broken interface. Thus, we could make sure which branch is broken. Then the OTDR is employed to trace the possible fault point. So, it could save energy and extend life of OTDR accordingly.
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