Monolithically Mode-Locked Semiconductor Quantum Dot Lasers
Lin Kuo-Jui (Gray)
|關鍵字:||量子點雷射;鎖模雷射;自相關光干涉儀;超快雷射;兆赫波輻射;Quantum Dot Lasers;Mode-Locked Lasers;Autocorrelator;Ultrafast Lasers;Terahertz Radiation|
50 GHz 且脈衝寬度小於5 ps 之超快雷射；其次將探討單區段電極架構之超長
（> 1.5 cm）共振腔的自鎖模與主動鎖模，並以擬購置的自相關光干涉儀來量
顫動等；最後將以乾式蝕刻DBR 反射鏡製作微共振腔（< 50 μm）之量子點
Semiconductor quantum dot (QD) lasers are based on self-assembled growth of QDs as gain medium. Their unique gain and absorption characteristics, which facilitate them simultaneously used as broadband gain medium and as fast saturable absorber, thus well suited for mode-locking applications. It is therefore very promising to investigate semiconductor mode-locked lasers monolithically implemented with QD gain medium. In this proposal, the mode-locking properties of QD lasers will be studied mainly based on our chirpy-stacked QD structure proposed in NSC96. The dependence of mode-locking on the layer design, such as layer thickness and modulation doping, will also be studied. First, passively mode-locked QD lasers will be fabricated by tandem configuration of gain and saturable absorption sections. The locking range will be determined in terms of gain current and reverse bias. The goal is to achieve ultrafast QD lasers with pulse repetition higher than 50 GHz and pulse width smaller than 5 ps. Then, the self-mode-locking as well as active mode-locking of single-section configuration with ultra-long cavity (> 1.5 cm) will be studied. The pulse parameters, such as pulse width, repetition rate, and timing jitter, will also be measured and analyzed by our proposed purchase of optical autocorrelator. Finally, edge-emitting QD microlasers with cavity length shorter than 50 μm will be fabricated with dry-etched DBR mirrors. The feasibility study of terahertz radiation by QD mode-locked lasers from such a short cavity will be carried out. We have to check if terahertz self-mode-locking could be observed in single-cavity configuration. Moreover, we should try to solve the processing difficulties to achieve terahertz passive mode-locking in tandem section configuration.