非同步約分諧波鎖模掺鉺光纖光固子雷射之研究

Abstract

非同步鎖模光纖光固子雷射在實驗以及理論上有相當多的研究及發展，它的許多特性，例如:脈衝的慢速週期性變化、提高超模的抑制比以及可形成超短且超高重複率的脈衝等，這些在高速光通訊與超快光學等的應用上都有很好的潛在價值。 在許多提高脈衝重複率的主動諧波鎖模掺鉺光纖雷射之研究□脈衝重複率會受限於電子儀器上之限制，利用約分諧波鎖模的機制可以來產生更高的脈衝序列重複率，但也會造成脈衝序列的不等高性。在文獻上解決的方法都必須利用其他的元件和機制來改善，而本論文則是藉由非同步鎖模機制來改善脈衝序列的振幅不等高性並同時有效地抑制超模噪音(supermode noise)，而不必像文獻上其他方法需依賴其他元件，此外脈衝寬度更可以輕易地小於1 psec，這也是目前其他約分諧波鎖模雷射所較難達到的成效。

Active harmonic mode-locked fiber lasers for high repetition rate optical pulse train generation will be limited by the electronic instrument speed. Rational harmonic mode-locking can further increase the pulse repetition rate but the pulse amplitude may not be perfectly equal. In the previous work additional components and mechanisms have to be used for achieving pulse equalization. In this thesis, by developing the new asynchronous rational harmonic mode-locking technique we not only improve the amplitude equalization of the pulse train well but also suppress the supermode noises effectively. Moreover, the achieved pulse-width can be easily shorter than one pico-second. This is one goal that other rational mode-locked fiber lasers couldn't achieve as yet.