- 學位論文
混合分波多工光纖網路傳輸效能之提昇
Performance Improvement of a Hybrid WDM-PON Transport System
摘要
在本論文中，我們提出兩個分波多工被動光纖網路架構，分別傳送有線電視類比訊號及OC-48數位訊號，探討使用外部光源注入技術對其傳輸效率及有線電視系統參數的影響。 首先，建構一分波多工光纖網路，以外部調變的方式來傳送有線電視類比及OC-48數位訊號，其類比訊號傳輸使用外調式分佈回饋式(Distributed FeedBack；DFB)雷射二極體，而OC-48數位訊號傳輸則使用外部光源注入技術，將可調式外部光源注入至法布立-拍若雷射二極體。此架構利用分佈回饋式雷射二極體其線性度、相對強度雜訊等較法布立-拍若雷射二極體佳的特性，來得到比法布立-拍若雷射二極體更好的有線電視訊號品質及系統參數，而數位訊號傳輸，使用外部光源注入到法布立-拍若雷射二極體，能達到數位訊號傳輸其誤碼率BER值必須小於10-9的系統要求。 其次，建構一分波多工光纖網路，以外部調變的方式來傳送有線電視類比及OC-48數位訊號，其類比及數位訊號傳輸均使用外部光源注入技術，將可調式外部光源注入至法布立-拍若(Fabry-Perot；FP)雷射二極體，得到外部光源注入技術可以明顯提昇法布立-拍若雷射二極體的傳輸特性及有線電視系統參數。達到與DFB雷射一樣好的系統參數，另外解多工後量測其數位訊號傳輸誤碼率(Bit Error Rate；BER)也可達到小於10-9的系統要求。 接著，我們於類比及數位混合分波多工傳輸系統中，於頭端光調變器串接單旁波帶濾波器，使其作用如單旁帶發射機，其訊號參數與BER值與雙旁波帶發射機比較，能達到一些改善。 最後，我們於類比及數位混合分波多工傳輸系統中，於接收端串接單旁波帶濾波器，使其能取代於頭端串接之單旁帶發射機，而又能達到降低系統複雜度及成本的目的。
關鍵字
有線電視 ； 被動光纖網路 ； 外部光源注入技術 ； 法布立-拍若雷射二極體 ； 分佈回饋式雷射二極體 ； 掺鉺光纖放大器 ； 分波多工器 ； 載波雜訊比 ； 合成二次拍差比 ； 合成三次拍差比並列摘要
In this paper﹐we proposed two WDM-PON systems﹒We transported CATV analog signals and OC-48 digital signals in the systems﹒We will discuss the affect of external light injection technique to transport effect and CATV system performance﹒ First﹐we proposed a WDM-PON system﹐in that﹐we used external modulation to transport CATV analog signals and OC-48 digital signals﹒We used distributed feedback(DFB) laser diode to externally modulated the analog signals﹒On the other hand﹐we used external light injection technique to transport OC-48 digital signals﹒The character of DFB LD is better than FP LD﹐so we could get better CATV performance and video quality﹒We injected external light into FP LD and get the BER less than 10-9﹒ Second﹐we proposed another WDM-PON system to transport CATV analog signals and OC-48 digital signals﹒We injected external light into FP LD to transport both analog and digital signals﹒We could obtain the result that external light injection technique could improve the transport character and CATV performance﹒The performance of CATV analog signals could be as good as in DFB LD transport part﹒The BER of digital signals transport could less 10-9 ﹒ An optical single sideband(SSB) modulation technique is proposed and demonstrated﹒Simultaneous transmission of CATV and OC-48 signals﹐good performance of CNR﹐CSO﹐and CTB were obtained for CATV signals；low bit-error rate were achieved for didital signal﹒ We present the investigation of the fiber Bragg grating(FBG) filter as an optical single sideband filter at the receiving site﹒The function of the optical SSB filter is employed to replace the optical SSB transmitter﹒Using simple FBG filter as an optical SSB filter in CATV and OC-48 transport system is a very attractive option﹐as it is passive and potentially low cost﹒