标题: | 超密波长分工及次载波有线电视系统的基本限制 Fundamental Transmission Limitations on both Ultra-Dense WDM and Subcarrier Multiplexed CATV Systems |
作者: | 吴明佳 Ming Chia Wu 尉应时 Winston I. Way 电信工程研究所 |
关键字: | 波长分工系统;次载波有线电视系统;光纤非线性;Wavelength Division Multiplexing System;Subcarrier Multiplexed CATV System;fiber nonlinearity |
公开日期: | 2003 |
摘要: | 本论文研究超密波长分工系统及次载波有线电视系统的基本限制. 主要分为四个部份: 在第一部分中, 我们分析了2.5 及10 Gb/s的超密波长分工系统在不同单模光纤中的传输限制并分析了周期性放大的系统在C波带的各项基本限制及最佳色散补偿比例. 第二部分, 我们发现在1550nm 外调式类比有线电视系统中, 自发性及外加相位调变必须同时考虑才能精准地预测二阶拍差, 特别是当外加相位调变的调变深度或频率高的时侯. 这个结果对长距离1550nm 外调式光发射机的设计有很重要的影响. 第三部分, 我们证明了用多个CW载波来模拟测试M-QAM次载波有线电视系统的准确度是在量测误差的范围内. 最后, 我们架设了世界第一个类比的光纤循环回圈并创造了78个频道64-QAM 1550nm次载波系统的最长传输记录-740km. This thesis investigates fiber nonlinearity limitation in both ultra dense wavelength division multiplexing (U-DWDM) digital systems and subcarrier multiplexing analog lightwave transmission systems. The main research results are organized into four parts. First of all, transmission performance of ultra-dense 2.5 and 10 Gbps NRZ IM/DD wavelength division multiplexing systems in various single-mode fibers is investigated. Fundamental limiting factors and their remedies by using optimum dispersion compensation for periodically amplified systems in C-band are presented. Second, we found that the combined effects of self- and external-phase modulations must be considered in order to precisely predict the CSO distortions in a long-distance 1550 nm externally-modulated AM-CATV system, especially when the applied phase modulation index and modulating tone frequency to the integrated phase modulator are high. This result has important implications to the optimum design of 1550 nm transmitter for long-distance AM- and QAM-CATV systems. Third, the validity of using multiple CW tones as the signal source to test the linearity of a multichannel M-ary quadrature-amplitude-modulation (M-QAM) subcarrier multiplexed (SCM) lightwave system was investigated. We consider the following representative optical fiber system nonlinearities: (1) laser clipping, and (2) the combined effect of laser frequency chirp and fiber dispersion. The results show that, if all orders of nonlinear distortions (NLDs) in a signal bandwidth are included in the total NLD power, the error caused by replacing M-QAM signals with CW tones can be within measurement uncertainty. Finally, a long-distance 1550 nm subcarrier multiplexed lightwave trunk system which transported 78 channels of 64-QAM signals was demonstrated in a recirculating loop experiment. Each channel can achieve a carrier-to-(noise + nonlinear distortion) ratio of 30 dB after 740 km transmission through conventional single-mode fiber without dispersion compensation. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT008513501 http://hdl.handle.net/11536/55667 |
显示于类别: | Thesis |
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