光激發式半導體雷射之時域動態表現：亮脈衝與亮暗脈衝對之間轉變現象

Abstract

本論文有系統探討具有線性共振腔之光激發式半導體雷射(Optically Pumped Semiconductor Lasers,OPSL)實現「自鎖模現象(self-mode locked,SML)」的標準，此光激發式半導體雷射是由具有散式布拉格反射鏡(Distributed Bragg Reflection,DBR)之半導體晶片、高激發功率二極體雷射及1片輸出鏡所共同組成，實驗結果揭示缺少「高階橫向模態(High-order transverse mode)」，無法產生連續自鎖模現象。 然而，不同於自鎖模脈衝形態，當微調輸出鏡產生Etalon effect時，雷射時域動態軌跡則會呈現「亮暗脈衝對(bright-dark pulse pairs)」形態，此外，進一步發現共振腔長在50-280mm範圍內，只要促使Etalon effect生成，都會產生「亮暗脈衝對」波形，這些實驗發現相信可為探索光激發式半導體雷射時域動態軌跡變化，提供一個新穎的觀點。

We systemmatically explore the criterion for achieving the self mode locking (SML) in an optically pumped semiconductor laser (OPSL) with a linear cavity. The OPSL consists of a semiconductor gain chip with distributed Bragg reflectors (DBRs), a high-power pump laser diode, and a concave output coupler. Experimental results reveal that the continuous SML operation cannot be achieved in the absence of high-order transverse modes. However, different from mode-locked pulses, the temporal traces display bright-dark pulse pairs at low pump power when the etalon effect caused by the output coupler is induced in the cavity. Moreover, it is experimentally found that bright-dark pulse pairs can be generated at the cavity length in the range of 50 to 280 mm as long as the etalon effect is induced. We believe that the present finding can provide a novel perspective for investigation of the temporal dynamics in OPSLs.