Open AccessHigh-temperature operating 8946nm-VCSELs with extremely low threshold for Cs-based chip scale atomic clocks
Author(s) -
Jianwei Zhang,
Xing Zhang,
Hao Zhu,
Jian Zhang,
Yongqiang Ning,
Li Qin,
Lijun Wang
Publication year - 2015
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.23.014763
Subject(s) - materials science , optoelectronics , vertical cavity surface emitting laser , laser , optics , chip , current density , wavelength , semiconductor laser theory , physics , semiconductor , telecommunications , computer science , quantum mechanics
We report on the design and fabrication of 894.6nm vertical-cavity surface-emitting lasers (VCSELs) with extremely low threshold at high temperatures, for use in chip-scale Cs atomic clocks. A new design method based on the analysis of the threshold gain and the desired carrier density for different active region structures was proposed to gain the low transparent current density. The increase of the threshold current at higher temperatures was successfully suppressed by introducing the large gain-cavity detuning of VCSEL. By detuning the gain-cavity mode to be -11nm, the minimum threshold current of only 0.23mA at 70 °C was achieved. The operating temperature for emitting the wavelength of 894.6nm was 110 °C, with the single mode suppression ratio (SMSR) of more than 25dB and the threshold current of only 0.32mA.