Browsing by Author "Hsieh, Pin-Hsien"

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Chirped multilayer quantum-dot mode-locked lasers with dual-wavelength and ground-state lasing emissions
(2019-01-01)
Chen, Yu-Chen
;
Hsieh, Pin-Hsien
;
Lin, Gray
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Monolithic passively mode-locked lasers are investigated based on chirped multi-layer InAs/InGaAs quantum-dot (QD) structure. The forward and backward tracings of light-current characteristics show two kinks and two hysteresis loops. The optical spectra reveal two lasing wavelengths around 1273 and 1230 nm, which are identified as two ground-state emissions of two differently chirped QD layers. The corresponding radio-frequency (RF) spectra of high-speed detector reveal two RF peaks at 16.21 and 16.03 GHz, which are attributed to fundamental mode-locking of two respective wavelengths. The laser pulses are confirmed by optical autocorrelator to exhibit dual-wavelength mode-locking. The pulsed characteristics of two lasing wavelengths are also discussed in terms of operating conditions. (C) 2019 Society of Photo-Optical Instrumentation Engineers (SPIE)
Digitally Chirped Multilayer Quantum Dot Lasers with Dual-Wavelength Lasing Emissions
(2019-06-01)
Sun, Yi-Jan Leo
;
Hsieh, Pin-Hsien
;
Lin, Gray
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The dual-wavelength lasing emissions of digitally chirped multilayer quantum dot (QD) lasers are investigated both experimentally and theoretically. The two lasing wavelengths are both identified as ground-state (GS) emissions but originated from different stacks of QD multilayers. The lasing spectra exhibited broadening and splitting properties by injecting more current. Moreover, the wavelength-resolved light-current characteristics reveal that first GS lasing intensity upon the threshold of second GS transitions neither saturates nor droops with increasing injection current, but increases with slightly reduced slope efficiency. A theoretical model is developed for digitally chirped multilayer QD lasers. The simulation results qualitatively reproduce the experimental observations.