混合鎖模摻鉺光纖雷射

Abstract

在本論文中我們結合了主動相位調變諧波鎖模、被動偏振旋轉疊加波鎖模與展波鎖模的技術成功地建構了一個可以提供大於1GHz重複率，小於10ps脈衝寬度的短脈衝雷射光源，並利用迴授電路來克服雷射共振腔腔長對溫度的變化所造成調變頻率的飄移，以及利用光的自相位調變加帶通濾波器來克服脈衝振幅不等的問題。在論文中，我們先對主被動鎖模雷射以及利用迴授電路結合非現性光學機制來穩定雷射輸出脈衝品質的原理作介紹，然後再敘述我們的實驗架構與結果。基本上，我們的雷射可以穩定的工作超過五個半個小時，輸出重複頻率為1.1 GHz、脈衝寬度為6.21ps光脈衝序列，脈衝之頻寬為0.5 nm，平均輸出功率約7.8mW，超模抑制比(Super-Mode Suppression Ratio)可穩定保持超過41dB以上。在論文末尾，我們也提出光路與電路的改善方式，以期能得到更高重複率、更短脈衝與更穩定的脈衝輸出。

In the thesis, by combining techniques of active harmonic mode-locking, passive polarization rotation additive pulse mode-locking and stretched-pulse mode-locking, we successfully set up a short-pulse light source which is able to supply optical pulse trains with greater than 1GHz repetition rate, smaller than 10 ps pulse width and above 40dB super mode suppression ratio. To overcome frequency detuning caused by cavity length variation, we also utilize a use of RF feedback circuit, the additive-pulse limiting technique and the combination of self phase modulation and optical bandpass filtering technique to achieve stable mode-locking. In the thesis, we first introduce the principles of active, passive and hybrid mode-locking lasers and then explain our experimental frameworks and results. On the whole, our laser is able to work stably over 5.5 hours, exporting pulse trains with width of 6.21ps and repetition rate of 1.1GHz. The average output power is 7.8 mW and the super mode suppression is above 41 dB. We also propose several ideas which may be helpful to improve the performance of optical cavity and electrical feedback circuit and hopefully we can get output pulses with higher bit rate, shorter pulse width, and more stabilized mode-locking quality.