| Summary: | 碩士 === 國立臺北科技大學 === 光電工程系研究所 === 101 === With the ubiquitous popularity of handheld devices, the demands on wireless and wired-line capacity have grown rapidly. The next generation communication systems require large data rate and broadband services highly. Radio-over-fiber (ROF), and fiber optical CATV systems are promising candidates to meet the demands in wireless and wire-lined optical access networks. ROF transport systems have the ability to offer significant mobility, economic advantage, and large capacity due to the characteristics of broad bandwidth and low transmission loss. In addition, fiber optical CATV systems are deployed widely to provide broad bandwidth to subscribers. Nevertheless, hybrid transmission of CATV/ROF combined signals has not been reported. A hybrid two-band transport system that uses different optical wavelength to deliver combined CATV/ROF RF analog signals would be quite useful for fiber networks providing telecommunication, Internet, and CATV services. However, it is a challenge to transmit RF, BB, and CATV signals simultaneously by using one optical fiber in a cost-effective way. In this project, we propose a symmetrically bidirectional CATV/ROF transport system based on lightwave modulated by phase modulators (PMs) with multi-wavelength output characteristic. Transmission performances over a 40-km single-mode fiber (SMF) transmission are studied. Different with the intensity modulation (IM) systems, the PM modulation ones utilize optical phase shifting to record signal state, which provides high robustness to against fiber nonlinearities with high gain and low noise figure. All of these benefits and no DC bias requirement characteristic make it popular in lightwave transport systems. With the help of only one optical sideband and optical single sideband (SSB) schemes at the receiving site, low bit error rate (BER) is expected to be achieved for ROF applications; as well as good performances of carrier-to-noise ratio (CNR), composite second-order (CSO), and composite triple beat (CTB) are expected to be obtained for CATV signal. Such a symmetrically bidirectional hybrid three-band transport system would be very attractive for trunk applications in advanced optical fiber transport and distribution networks, for provisioning full services including telecommunication, Internet, and CATV broadband integrated services.
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