本篇論文，提出使用以連續波放射的980 nm的雷射二極體做為雷射激發源，應用模態場面積不匹配理論，採用摻鉺的可飽和吸收光纖來Q切換摻鉺雷射，產生在S-band 內的1510 nm Q切換脈衝，隨之而來產生在L-band 內的1570 nm增益切換脈衝。在雷射輸入功率為175 mW之下，產生的脈衝能量為3.8 μJ、脈衝寬度為0.27μs、脈衝的重複速率為1.7kHz，而且速率隨著輸入功率提高而增加。另外，以速率方程式為基礎，來搭配實驗內容所做出的數值模擬分析，獲得的數值結果與實驗結果相近，而且可以說明Q和增益切換雙脈衝的自平衡機制。在所有做過全光纖被動式Q切換摻鉺雷射的文獻當中，本實驗驗證了第一個可在S-band產生脈衝的摻鉺光纖雷射。

The thesis demonstrates a 980-nm continuous-wave pumped all-fiber erbium laser passively Q-switched at 1510 nm and gain-switched at 1570 nm. By the mode-field-area-mismatch method, we use an Er3+-doped saturable absorber fiber to Q-switch an erbium fiber laser. The sequentially Q-switched-1510-nm pulses have pulse energy of 3.8 μJ, pulse width of 0.27 μs, and pulse repetition rate of 1.7 kHz which linearly varied with the pump power. The data of numerical simulation based on the rate equations is in a good agreement with the experiment result, thereby verifying the self-balanced mechanism between Q-and gain-switched pulses. To the best of our knowledge, we demonstrate, for the first time, an erbium fiber pulsed laser at S-band.

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