光纖放大器之模擬

Abstract

本論文利用原子躍遷的速率方程式及光功率傳播方程式，針對摻鉺光纖放 大器的特性作數值模擬，以研究摻鉺光纖放大器的增益與雜訊特性。在發 展出一套可用的模擬程式後，我們進而利用此程式來探討一種新型的定增 益光纖放大器。這種新型的放大器係在光纖放大器的兩端加上光纖光柵構 成雷射共振腔，用以控制光纖放大器的增益為定值。當雷射共振時，載子 分佈會被鎖在一固定值（由共振腔的損耗來決定），從而在別的波長的增 益也被鎖在一固定值上，與激發光的功率無關。即使有不定數目波道的信 號同時輸入，其增益特性也相差無幾。 In the thesis, we develop a simulation program of Er-doped fiber amplifiers based on the rate equation model. Aftering studying the gain and noise characteristics of conventional Er- doped fiber amplifiers, we then use our program to design a new type of Er-doped fiber amplifiers --the gainlocked Er-doped fiber amplifiers. In such new type of fiber amplifiers, two fiber gratings are used to form a laser cavity which is designed to lase atwavelength different from the signal wavelength. Once lasing occurs, thepopulation inversion is pinned at a certain level(determined by the cavity loss) and the amplification gain at the signal wavelength is also pinned regardless what is the pump power. The amplification gain will remains almost constant even though there are several signal channels with different signal powers.