中 文 摘 要

由於分佈式拉曼光纖放大器在數位光纖通信系統日益受到重視，其發展技術也日趨成熟，但在類比光纖有線電視(CATV)系統中卻尚未見討論，因此在本論文中，我們首先探討拉曼放大器在類比光纖有線電視上之特性以及可行性。研究中，首先利用4顆波長為1460 nm、1470 nm、1480 nm、1490 nm的半導體雷射作為拉曼放大器的幫激雷射，我們發現，當使用拉曼光纖放大器於CATV系統中時，經過25km LEAF (Large Effect Area Fiber)光纖傳輸，其CNR (Carrier-to-noise Ratio) 約為46.4~49.5 dB，相較於B-B (Back-to-Back)的架構中約有1~2dB的劣化，相較於僅僅使用摻鉺光纖放大器放大信號的系統架構中也有劣化約1~1.5 dB，推究使用拉曼放大器造成CNR劣化之主要原因為幫激雷射在光纖中所產生的拉曼自發性輻射與信號本身的光源自發性輻射(Source Spontaneous Emission, SSE )效應所累積之雜訊所致，我們利用關掉影響信號雜訊最大的幫激雷射( 1460 nm )之功率以降低其信號處之雜訊，發現其CNR約有了0.5~1.0 dB的改善，驗證了幫激雷射所造成系統上CNR之劣化。在長距離80km的傳輸上，CNR也因為摻鉺光纖放大器產生的放大自發性輻射(ASE)經過光帶通濾波器所殘餘的雜訊以及分佈式拉曼放大器產生的拉曼自發性輻射與信號本身的光源自發性輻射( Source Spontaneous Emission, SSE )相互所累積的雜訊而造成此系統中CNR而有嚴重之劣化(CNR：45.2~47.3 dB)。本研究結果發現分佈式拉曼光纖放大器在於類比之CATV系統上並不可行，原因為它所產生的拉曼自發性輻射與信號本身的光源自發性輻射所產生的雜訊將嚴重劣化系統之CNR值。這樣的結果，將可提供未來探討拉曼放大器應用於類比光纖有線電視設計所會產生之問題作為參考。

Abstract
In this paper, we build up the DRA (Distributed Raman Amplifier) by using four pump LDs (1460nm, 1470nm, 1480nm, 1490nm) with 25km LEAF (Large Effect Area Fiber) to transmission and compared the performance with system that just have EDFA. For the long distant system, we use EDFA and DRA to transmit 80km LEAF. In order to increase the system power budget it is necessary to use the two optical amplifiers in the same time.
For the experimental results, we find that use the Raman amplifier with 25km LEAF may have degradations of CNR, CSO, CTB with 1~2 dB, 2 dB and 2~3 dB compared to Back-to-Back configuration, consider the reasons for the CSO and CTB degradations are due to the fiber dispersion and nonlinearly effect (SPM) in transmission process, and the pumps generate the high Raman spontaneous emission and source spontaneous emission are the main reasons to degrade CNR. We try to find the pump laser which effects signal noise largest (1460 nm LD) and turned off it, then CNR have about 0.5~1.0 dB improved.
In the long distant transmission pass through 80km LEAF, the performances of CNR, CSO, CTB have serious decay. Because of the ASE generated from EDFA and Raman spontaneous emission and source spontaneous emission generated form Raman amplifier accumulate each other to made the CNR decay. For the long distance fiber dispersion and fiber nonlinear effect (SPM) also made CSO, CTB have degradations in the system, the CNR is about 45.2~47.3 dB, CSO is about 72.3~75.9 dBc , CTB is about 67.4~71 dBc. For this result, we know that DRA is not suitable applied in analog CATV system for the serious degradation of CNR. The study may give a reference to discuss Raman amplifier in the analog CATV system in the future.

內容目錄
頁次
誌謝…………………………………………………………………Ⅰ
中文摘要……………………………………………………………Ⅱ
英文摘要……………………………………………………………Ⅲ
內容目錄……………………………………………………………Ⅳ
附圖目錄……………………………………………………………Ⅴ
附表目錄……………………………………………………………Ⅶ
第一章 簡介………………………………………………………..1
1.1 研究背景………………………………………………….1
1.2 研究動機………………………………………………….2
1.3 論文結構………………………………………………….2
第二章 基本原理簡介……………………………………………..3
2.1 有線電視之量測參數定義……………………………….3
2.2 摻鉺光纖放大器的基本原理…………………………….6
2.3 分佈式拉曼光纖放大器之基本原理…………………….10
2.4 拉曼幫激雷射功率合波器……………………………….14
第三章 拉曼光放大之有線電視系統實驗………………………..15
3.1 量測系統架構…………………………………………….15
3.2 實驗結果………………………………………………….17
3.3 討論……………………………………………………….19
第四章 結論………………………………………………………20
參考文獻……………………………………………………………21
附表…………………………………………………………………23
附圖…………………………………………………………………26

參考文獻
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