Open AccessComparison of static and dynamic characteristics of 1550 nm quantum dash and quantum well lasers
Author(s) -
Bei Shi,
Sergio Pinna,
Wei Luo,
Huajun Zhao,
Si Zhu,
Simone Tommaso Šuran Brunelli,
Kei May Lau,
Jonathan Klamkin
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.399188
Subject(s) - laser , lasing threshold , optoelectronics , quantum well , materials science , optics , quantum dot laser , semiconductor laser theory , modulation (music) , physics , acoustics
Compared to quantum well (QW) lasers, lower dimensional quantum dot (QD) or quantum dash (QDash) devices demonstrate superior performances, owing to their quantized energy levels and increased carrier confinement. Here, we report the systematic comparison of static and dynamic properties of long wavelength (1550 nm) QDash and QW lasers. For the QDash lasers, a higher maximum operating temperature and lower temperature dependence was achieved for long cavities, although the threshold current densities were larger than the QW reference devices. The lasing characteristics for QDashes are significantly improved following the application of a high reflectance (HR) coating on the rear facets. The QDash lasers also exhibit three orders lower dark current, of 45 µA/cm 2 under -1 V reverse bias. Small signal modulation on the 4 × 550 µm 2 Fabry-Perot cavities yields a modulation efficiency of 0.48 GHz/√mA and a maximum 3-dB bandwidth of 7.4 GHz for QDashes, slightly larger than that for the QW devices. Meanwhile, a stronger damping effect was observed for the QDash lasers due to their lower differential gain.