利用皮秒脈衝頻譜塑形技術於全正色散摻鐿光纖雷射啁啾脈衝放大系統之實驗及理論研究

Experimental and Theoretical Studies of Chirped-Pulse Amplification of Spectrally Shaped Picosecond Pulses from an All-Normal Dispersion Yb-Fiber Laser

黃聖文(Huang, Sheng Wen)

指導教授 ： 潘犀靈

國立清華大學/電機資訊學院/光電工程研究所/碩士(2015年)

摘要

本論文中，我們以頻譜塑形技術設計一台中心波長為1064奈米的摻鐿光纖啁啾脈衝放大器。種子光源為一台全正色散被動鎖模光纖雷射，初階放大器與主要放大器分別採用10微米與30微米纖核直徑的非極化保持摻鐿光纖。雷射脈衝重複率約為15 MHz，頻譜寬度約為9 奈米，輸出功率可達28 瓦。實驗結果顯示，此脈衝經過光纖放大器後無法壓縮回次皮秒脈衝。經由非線性薛丁格方程式數值模擬結果得知，頻譜寬度及頻譜形貌皆會影響脈衝壓縮品質，其中頻譜形貌影響甚劇。因此，我們在種子雷射腔外使用帶通濾波器進行頻譜塑形，使種子光源頻譜形狀更貼近高斯形貌。經由這種簡易的頻譜塑形後可獲得更短而品質更好的脈衝，其最高輸出脈衝能量可達約2微焦耳。在最佳非線性效應條件下，經由脈衝壓縮後，本雷射系統輸出脈衝之最高尖峰功率可達60千瓦，半高全寬約350飛秒，主要脈衝包含40%的脈衝能量。

關鍵字

啁啾脈衝放大器 ； 摻鐿光纖放大器 ； 頻譜塑形 ； 全正色散被動鎖模光纖雷射 ； 次皮秒脈衝

並列摘要

In this thesis, we studied experimentally and theoretically spectrally shaped chirped pulse amplification (CPA) of a high-power ytterbium-doped fiber laser amplifier with a central wavelength at 1064 nm. The seed source is an all-normal dispersion (ANDi) passively mode-locked fiber laser. For the amplified stages, we employ the 10 m-core and 30 m-core non-polarization maintaining Yb-doped fiber to be used in the pre-amplifier and main amplified stages respectively. The seed laser generated pulses with a repetition rate of ~15 MHz, spectral bandwidth ~ 9 nm and an output power of 28 W. According to the numerical simulation results of the nonlinear Schrodinger equation (NLSE), both spectral bandwidth and spectral profile of the seed laser would affect the outcome of pulse compression. Especially, the spectral profile of the seed pulse plays a dominant role. Thus, a spectral filter was employed such that the spectrum of the seed laser output was Gaussian-like. The maximum output of the pulse energy can be as high as 2.0 J. The peak power of the best compressed pulse was ~ 60 kW and the pulse duration was as short as 350 fs (FWHM). Approximately 40% of the pulse energy is in the main pulse.

並列關鍵字

Chirped-pulse amplification ； Yb-doped fiber amplifier ； spectral shaping ； All-normal dispersion fiber laser ； sub-picosecond pulses

參考文獻

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