以半導體為增益組成被動鎖模光纖雷射之理論研究

Abstract

我們成功的提出有關半導體光放大器與非線性偏振演化的理論模型與模擬結果。利用結合非線性偏振演化與半導體光放大器內動態增益可以有效獲得壓縮或拓寬鎖模脈衝。 此理論結果與我們的實驗成果是互相符合的。 我們理論指出當一個0.02 pJ， 2 ps寬的高斯脈衝經過半導體光放大器後會在縱向與橫向電磁波間產生一個1.2 rad 的非線性相位差。而在環形共振腔的雷射理論模擬系統中，我們可利用適當的調整光纖極化控制器來獲得一穩定0.16pJ，670 fs的短脈衝與14.8pJ和5ns的方型波。

We have successfully presented a theoretical model and simulation results including a SOA and nonlinear polarization evolution. A mode-locked train of narrow and broaden pulses is obtained by combining nonlinear polarization rotation and the dynamics gain in the SOA. The pulse narrowing and broadening process is demonstrated numerically and good qualitative agreement with experiments in our previous work is achieved. Our simulation shows that the nonlinear phase shift between TE and TM after one roundtrip, which was found to be more than 1.2rad when the input pulse energy is 0.02pJ (2ps Gaussian pulse).In ring cavity system, the pulse has been shorted further to the ultimate width of 670fs and energy 0.16pJ, and can been broadened further to the width of 5ns and energy 14.8pJ after several roundtrips.