將次載波分工技術應用於波長分工及擷取光纖網路之研究

Abstract

在本論文中, 我們從事將次載波分工技術應用於波長分工及擷取光纖網路 之研究 o 我們的研究主要分為三類 : (1) 用於高速分封交換之 DWDM 網 路之鏈結技術, (2) 用於被光拍差現象嚴重干擾之 PON 網路多重擷取技 術, 以及 (3) 以光纖為傳輸媒介之無線個人通訊系統 o 在應用 (1) 中, 我們提出了兩種 SCM-based 網路鏈結技術 : hopping P3 以及 PPCS 鏈 結技術 o 我們結合光接收器陣列與高頻交換元件, 實現一個四節點之 Gigabit DWDM 網路原型, 並以實際展示這兩種網路鏈結技術的可行性 o 在應用 (2) 中, 我們提出將 Walsh-code-based S-CDMA 技術應用於有嚴 重光拍差及同頻道干擾的PON 網路中, 以達到介質多重擷取的目的 o 我 們以實驗的方式, 展示此構想的可行性 o 在應用 (3) 中, 我們主要探討 在直調式及外調式光纖通訊系統中, 靜態及動態截波非線性失真對大訊號 SFDR 效能的影響 o 我們藉由所推導的理論公式, 預測理想的 LD 及數種 線性化後的外調式調變器, 其大訊號 SFDR 效能之理論上限 o 此外, 我 們也預測 LD 在弱截波失真下, 由動態截波現象所產生之非線性干擾 我們亦以電腦模擬及實驗的方式, 驗證所推導理論的正確性 o In this dissertation, we study the applications of subcarrier multiplexed (SCM) based technologies in dense wavelength-division-multiplexing (DWDM) and access optical networks. The studies are classified into three categories : (1) signalling techniques in the gigabit packet-switching DWDM networks, (2) optical beat interference (OBI) reduction techniques in multiple access passive optical networks (PON's), and (3) fiber-based microcellular/ personal communication systems (PCS's). In application (1), we proposed two SCM-based signalling techniques, including parallelly processed hopping pilot-tones (hopping P3) signalling technique and parallelly processed coded subcarriers (PPCS) signalling technique. We have also experimentally demonstrated the feasibility of using these two techniques in a four-node gigabit DWDM network. In application (2), we proposed and experimentally demonstrated the feasibility of using Walsh-code-based synchronized code- division-multiple-access (S-CDMA) technique to achieve multiple access in the presence of extremely severe OBI and co-channel interference. In application (3), we investigated the large- signal SFDR performance due to static and dynamic clipping in direct and external modulation systems. A closed-form analysis is presented to predict the theoretical upper-bound for large- signal spurious-free dynamic range (SFDR) in an ideal laser diode (LD) and external modulators with various linearization techniques. In addition, we have also used the analysis to predict the dynamic-clipping-induced nonlinear distortions (NLD' s) in a weakly clipped LD. The validity of our analysis is confirmed through computer simulation and actual measurement in a typical CATV-quality DFB LD.