- 期刊
一種架構於近乎正交布雷格光纖光柵之非同調光纖分碼多重進接網系統
An Incoherent Optical CDMA Networking System Structured with Nearly Orthogonal Bragg Fiber-Gratings
摘要
本文構想出一種適於非同調光纖分碼多重進接網路系統的頻域編解碼裝置，此編解碼裝置是根據預先蝕刻於布雷格光纖光柵的近乎正交序碼的良好相關特性來設計。我們在光柵光纖內預寫入對應於最大長度序碼（m-sequence codes）的布雷格波長序碼列，則類如發光二極體的寬頻光源訊號將被切剖成好幾個波頻細片元（spectral chips），每個波頻細片的中心波長都不同且分佈在入射光源的頻寬之中。一個周期長度為Ｎ的最大長度序碼，可以提供Ｎ個不同位移循環的序碼語句給Ｎ位多工使用者，造到Ｎ倍的分碼多工網路系統容量。光纖分碼多重進接系統在每個接收端往往會遭遇到其他使用者所造成的多重擷取干擾（Multiple-Access Interference, MAI），這使得接收端易於發生錯誤，降低系統的性能。透過最大長度序碼的移位－相加（shift-and-add）族群特性以及搭配新式的編解碼器設計，就能適切地排除多重擷取干擾的影響，這不僅降低了錯誤率的發生，也大大提升了整個系統的性能。
並列摘要
This paper devises a spectral coding scheme for incoherent optical code-division multiple-access (OCDMA) networks. The spectral coding is based on the pseudo-orthogonality of OCDMA codes properly written in the fiber Bragg grating (FBG) devices. For an incoming broadband optical signal having spectral components equal to the designed Bragg wavelengths of the FBG, the spectral components will be reflected and spectrally coded with the written address codes. Each spectral chip has different central wavelength and is distributed over the spectrum of the incoming light source. To overcome the limiting factor of multiple-access interference (MAl) of OCDMA network, FBG decoder is configured on the basis of orthogonal correlation functions of the nearly orthogonal m-sequence codes. An intended receiver user that operates on the defined orthogonal correlation functions will reject any interfering user and obtain a quasi-orthogonality among the OCDMA users in the network system.
延伸閱讀
- 王昭惟（2019）。數位光纖無線整合技術兼容密集分波多工的無允諾上傳前傳系統〔碩士論文，國立清華大學〕。華藝線上圖書館。https://www.airitilibrary.com/Article/Detail?DocID=U0016-0206202016191482
- 郭萱侑、江柏俊（2005）。Branched Fiber Network Optical Monitoring Technology。電腦與通訊，(113)，19-25。https://doi.org/10.29917/CCLTJ.200509.0004
- 黃振發、張耀堂（2001）。Fiber-Optic CDMA Scheme for Suppressing Multiple-Sources Interference in CATV Networks。網際網路技術學刊，2(1)，19-24。https://doi.org/10.6138/JIT.2001.2.1.03