近幾年來，光通訊的高傳輸需求快速上升，波長多工有效地運用，光纖的頻寬並提升系統傳輸量，但是卻因為色散而限制了傳送距離。

而我們可用加入某些裝置和元件在系統中，來達到我們想要的色散的補償，如色散補償光纖、光纖布拉格光柵或是數位電子信號處理電路等光纖色散補償技術。但是使用這些技術在系統上，雖然解決了色散的問題，但是仍然存在某些缺點。

在多重環狀被動光纖網路架構中，所有環路的總長度往往會超過200公里，為了使此種環狀網路的架構簡單化，我們希望在此種網路中避免使用到如色散補償光纖、光纖布拉格光柵或是數位電子信號處理電路(DSP Circuits)等光纖色散補償技術。因此設計一個可容忍高達200公里累積色散的發射機是必要的。

光倍二位元信號模式(Optical Duobinary Modulation)是具潛力的高速光纖數位通訊信號模式。最主要的原因，
(1)擁有較小的信號頻寬，約為一般非歸零數位信號(Non-Return to Zero, NRZ)的一半，
(2)高頻寬使用效應，
(3)高色散(chromatic dispersion)抵抗能力，
(4)可以利用直接解調(Intensity modulation direct detector)的方式還原信號，
(5)在都會型區域網路不需用到任何的補償裝置，更適合佈放在台灣地小人稠的地理環境。

在這篇論文中，我們介紹了如何的架設出光倍二位元系統，並產生出光倍二位元信號，模擬並實驗使用不同的驅動電壓和使用不同大小的倍二位元濾波器，會對於信號和頻譜有什麼樣的影響，並對不同的驅動電壓最佳化的濾波器大小，以得到最佳化的系統效能。

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