使用濾波器及光相位共軛器的光固子傳輸

Abstract

本論文主要在研究使用光濾波器及光相位共軛的光固子傳輸系統，並 且探討在波長 多工的光固子通信系統中的四波混合效應。 在二個改進光固子傳輸的方法中，其一是在每個光放大器之後加上光濾波 器，以穩定光固子載波的頻率。首先，在使用固定頻率的光濾波器及考慮 光固子的穩定性、交互作用以及Gordon-Haus效應的限制下，得到不同距 離最大的傳輸速率。接著，我們比較向上、向下滑動頻率濾波器對減少光 固子相互作用的效果，並提出最有效的交錯式滑動，可提高光固子通訊之 傳輸速率。在Butterworth及Fabry-Perot濾波器的比較中，我們發現 Butterworth濾波器壓縮光固子可更進一步減低光固子的交互作用。另一 方法是使用光相位共軛器。如相鄰兩光固子相位差在90o以上時，光相位 共軛器甚至加在脈衝變形時，光固子仍可還原。實際上光濾波器及光相位 共軛器可混合使用來促進光固子的傳輸。 In this thesis, we mainly study the optical soliton transmission system with filters and optical phase conjugation. The four wave mixing effect in a wavelength- division-multiplexing soliton transmission system is also presented as an additional contribution. Both methods can be used to improve the soliton transmission. One is touse a filter after each optical amplifier. The filter with fixed centerfrequency stabilizes the carrier frequency of the soliton and the maximumbit rates limited by the stability, soliton interaction, and Gordon-Haus effect are obtained in different distance. Furthermore, we show the effectsof the up- sliding and down-sliding frequency filter on the soliton interactionand propose the most effective zigzag-sliding frequency guiding filter ofwhich the center frequency is alternatively up-sliding and down-sliding alongthe fiber. Finally, we will compare the sliding frequency Butterworth filterand Fabry- Perot filter. The other is to use the optical phase conjugation.When the neighboring solitons with phase difference larger than 90o, theundoing of the soliton interaction is well. In fact, the filter and opticalphase conjugation can be combined to control the soliton transmission.