摘要
本論文研究主動式Q-開關的摻鉺光纖雷射，在共振腔結構上分別使用環形和線性兩種共振腔結構來建構光纖雷射，在脈衝產生的機制上應用電光調制器和聲光調制器來作為Q開關，以產生短脈衝的雷射光。為了得到高峰值功率的雷射光輸出，在比較三種光纖雷射結構後，所採用的線性共振腔是由對1550nm光具有高反射的反射鏡以及光纖垂直端面的反射所構成，脈衝壓縮上是採用聲光調制器作為Q-開關，實驗中分別討論幫浦光功率、脈衝重複率、高Q值工作週期的比例、以及摻鉺光纖長度等參數，對於脈衝峰值功率和脈衝寬度的影響。實驗結果顯示，提高幫浦光功率、降低脈衝重複率、縮短高Q值工作週期，有助於提高脈衝的峰值功率以及縮短脈衝寬度。在最佳峰值功率(較高脈衝重複率)的情況下，使用長度為2.25公尺的高濃度摻鉺光纖之主動式Q-開關摻鉺光纖雷射，在脈衝重複率為0.3kHz(1kHz)、幫浦光功率為400mW時，可得到峰值功率高達810W(718W)、脈衝寬度為30ns(45ns)的雷射脈衝。
並列摘要
In this work, an active Q-switched erbium doped fiber laser is studied. In the experiment, the linear and the ring structures of the laser cavity are used, and the electro-optic and acousto-optic modulators are utilized as the Q-switch. After comparing three fiber laser structures, the high-peak power Q-switched fiber laser adopts the linear laser cavity formed by the reflection mirror with high reflectivity at 1550nm and the perpendicular fiber end. In the pulse compression process, the acousto-optic modulator is used as the Q-switch to produce the pulse with short duration. In the experiments, the effects of pump power, pulse repetition rate, high-Q duty cycle, and erbium-doped fiber length, on the pulse peak power and pulse duration, are discussed. Experimental results show that high pump power, low repetition rate, and short high-Q duty cycle facilitate the enhancement of pulse peak power and reduction of pulse duration. Under the condition of optimal pulse peak power (high repetition rate), the pulse with peak power of 810W (718W) and pulse duration of 30ns (45ns) is produced in the erbium doped fiber laser using erbium doped fiber length of 2.25m with repetition rate of 0.3kHz(1kHz) and pump power of 400mW.