驅動雷射二極體並利用光固子壓縮技術產生次皮秒光脈衝之研究

Abstract

本篇論文中，是利用非線性光學中的光固子效應來產生一個壓縮脈衝光。並針對以光固子效應壓縮中的缺點，進行相關的處理。最後並達成一完整乾淨的壓縮脈衝，其脈衝寬度由原始的24皮秒壓縮到622飛秒。 其中，在原始脈衝的部分，是利用外接射頻增益開關的方式來調變，並產生基本脈衝。在線性壓縮脈衝方面，是利用高負色散的光纖，使得存在於光脈衝的啾頻與其色散現象相互作用，進而達成光脈衝壓縮。而非線性壓縮脈衝，則是利用光固子的效應，自相位調變現象與光纖中之色散現象相互作用，並在最佳的一個長度上，擷取出在作用中最窄的壓縮脈衝。但由於在此壓縮脈衝的機制中，會產生一很大的底盤效應，使得產生之脈衝品質變低。有鑑於此，產生出來的光壓縮脈衝必須再處理，而處理方式，是利用光纖非線性現象中的雙折射效應，讓不同的光強度，產生不同的相位差，不同的偏振態，用已去除底盤，而達到一個無底盤效應的乾淨非線性壓縮脈衝。

In this thesis, we use soliton effect to generate a compressed pulse. An inherent drawback of the soliton-effect compression pulse has a large pedestal. We also remove it and get a quality good pedestal-free pulse. In our experimental result, the pulse width is compressed from 24ps to 622fs. The basic optical pulses, it uses the RF signal to modulate. It is so-called Gain-Switched modulation and obtains a 20~30ps pulse. In the linear pulse compression, the negative high dispersion fiber compensates negative chirped pulse. The pulse width can be compressed to 7ps. Furthermore, the nonlinear pulse compression uses a piece of optimum fiber length to compress linear pulse compression. It employs SPM and GVD interplay in a fiber. It also needs a high peak power to generate nonlinear effect. It compresses once more and pulse width is 622fs. But the pulse has a large pedestal. Finally, we use the intensity discriminator to remove pedestal. It uses the intensity dependent birefringence effect in optical fibers and to realize pedestal free nonlinear compressed pulse. The pulse width is equal to nonlinear pulse compression pulse.