Spectral dynamical behavior in two-section, quantum well, mode-locked laser at 1.064 μm Project supported by the National Basic Research Program of China (Grant Nos.~2013CB933304 and 2012CB932701), the National Natural Science Foundation of China (Grant Nos. 61274125 and 61435012), and the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB01010200)

• Published in: Chinese physics B 2017-06, Vol.26 (7)
• Main Authors: Wei, Si-Hang, Ma, Ben, Chen, Ze-Sheng, Liao, Yong-Ping, Hao, Hong-Yue, Zhang, Yu, Ni, Hai-Qiao, Niu, Zhi-Chuan
• Format: Article
• Language: English
• Subjects: blue-shift; mode-locked laser; saturable absorber; thermal effect
• ISSN: 1674-1056
• DOI: 10.1088/1674-1056/26/7/074208

In this study, two-section mode-locked semiconductor lasers with different numbers of quantum wells and different types of waveguide structures are made. Their ultrashort pulse features are presented. The spectral dynamical behaviors in these lasers are studied in detail. In the simulation part, a two-band compressive-strained quantum well (QW) model is used to study thermally induced band-edge detuning in the amplifier and saturable absorber (SA). A sudden blue shift in laser spectrum is expected by calculating the peak of the net gain. In the experiment part, the sudden blue shift in the emission spectrum is observed in triple QW samples under certain operating conditions but remains absent in single QW samples. Experimental results reveal that blue shift phenomenon is connected with the difference between currents in two sections. Additionally, a threshold current ratio for blue-shift is also demonstrated.