使用光纖分碼多工技術解決有線電視傳輸之多光源干擾問題

Abstract

在本論文中探討藉由光分碼多重存取（OCDMA）展時的觀念，以解決有線電視上行網路的多光源干擾問題。在上行鏈路基於經濟與效率成本之考量，CATV光源之選用均不具備溫度控制與波長穩定度之效能。如此在Local Loop架構下極易造成多光源干擾之問題，此舉嚴重影響CATV整體效能（SIR）暨服務用戶數量〔1〕。本論文提出以光分碼多工技術來取代傳統光展頻技術，將可有效抑制多重存取（MAI）與光拍差干擾（OBI）。並說明使用最大長度序碼（M-sequence）架構於布雷格光柵之OCDMA架構設計，解決CATV上行鏈路多光源干擾問題。並實現經效率與安全鎖碼的功能。An optical code-division multiple-access (OCDMA) scheme is introduced to solve the interference problem among optical signal sources in the CATV networks. Due to the cost and efficiency consideration on the CATV up-link, the optical sources are commonly not provided with temperature control and wavelength stability. This leads to the mutual interference of multiple optical sources in the framework of. Local Loop. In the discussed optical CATV transmission networks, digital TV signals from multiple users are spectrum-coded in the pseudo- orthogonal M-sequence coded fiber Bragg gratings (FBG) to attain time spreading. The scheme can overcome the multiple-access interference (MAI) and the optical beat interference (OBI) among multiple optical sources and is applicable for CATV up-link network.