| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 101 === In this thesis, we studied on unidirectional and bidirectional transmission wavelength division multiplexing passive optical networks (WDM-PONs). The transmission distances for various experiments are approximately 25-35 km in each case. There are included various devices in bidirectional WDM PONs. For example, the array waveguide gratings, fiber Bragg gratings and thin film filters, and optical amplifier. Also, bidirectional WDM PON provides WDM characteristics and save the fiber.
For setting of monitoring system, we established bidirectional transmission WDM PON. The wavelengths for transmission ranges are from 1580 nm to 1587 nm in L-band with channel spacing of 1.6 nm. After verified the proposed system, we added optical time domain reflectormeter (OTDR) for monitoring purpose. The built-in light source for the OTDR is a C-band broadband source ranges 1535 nm ~ 1550 nm. Four optical network units (ONUs) could be simultaneously monitored. The bit error rate (BER) performances were also measured and we found that the power penalty is less than 0.6 dB at 10-9 BER.
In order to compensate for signals loss when transmission distance in extended, we used a remotely pumped laser diode to excite erbium-doped fiber for signals amplification. The pump wavelength is at 1480 nm and the distance between pump laser source and erbium-doped fiber (EDF) is 12 km. Experimental setup was implemented by using 2, 4, 5, and 6 m erbium-doped fibers in each case for analyses and comparison. Using remotely pumped, the power penalty is about 0.64 dB, which is still in an acceptable range.
Finally, we integrated remotely pumped amplifier and OTDR monitoring functions in a bidirectional WDM PON system with good performance. With merit of double transmission capacity, this system is promising for future WDM PONs application.
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