| Summary: | 碩士 === 國立臺北科技大學 === 光電工程系研究所 === 96 === In the thesis, we propose various types of transport system, which include architectures of analog transport system, digital transport system, full-duplex ROF transport system as well as employing semiconductor optical amplifier (SOA) with external light injection technique, optical single sideband (SSB) modulation technique and different ways to compensate dispersion to overcome performance of transport systems.
First, the experimental system configuration of our proposed directly modulated CATV transport systems using NDF as the transmission medium. Using this negative dispersion property to compensate for the laser chirp and results in a system with better transmission performance.
Second, a cost-effective architecture is proposed for deployment in digital transport systems, as demonstrated by the vertical cavity surface emitting lasers (VCSELs) and semiconductor optical amplifier (SOA) with external light injection technique. VCSEL is gradually used to replace DFB laser diodes for the 1.55μm wavelength band in lightwave transport systems, because it’s with a single mode with narrow linewidth and low cost. Amplify the optical signal by using SOA to replace EDFA, and use the external light injection technique to reduce the SOA-induced distortion and crosstalk.
Third, extend previous topic, we use four VCSELs to reduce transmission speed
to build a simple architecture, a 10 Gbit/s wavelength-division-multiplexing (WDM) transport system over a 50 km SMF. Improved bit error rate (BER) performance was observed under direct modulation of four channels at 2.5 Gbit/s, attributed to the SOA light injection technique to reduce the SOA-induced distortion and crosstalk.
Finally, we integrate digital and analog system to propose and demonstrate a full-duplex radio-on-fiber (ROF) transport system based on optical single sideband (SSB) modulation, wavelength-division-multiplexing (WDM) and optical add-drop multiplexing techniques, By using optical SSB format, RF power degradation due to chromatic dispersion can be reduced and thus systems’ performances can be improved. WDM and optical add-drop multiplexing techniques can simplify the network architecture and upgrade the deployment of BS since they enable full-duplex operation on one fiber.
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