Theory for n-type doped, tensile-strained Ge-Si(x)Ge(y)Sn1-x-y quantum-well lasers at telecom wavelength.
We propose and develop a theoretical gain model for an n-doped, tensile-strained Ge-Si(x)Ge(y)Sn(1-x-y) quantum-well laser. Tensile strain and n doping in Ge active layers can help achieve population inversion in the direct conduction band and provide optical gain. We show our theoretical model for the bandgap structure, the polarization-dependent optical gain spectrum, and the free-carrier absorption of the n-type doped, tensile-strained Ge quantum-well laser. Despite the free-carrier absorption due to the n-type doping, a significant net gain can be obtained from the direct transition. We also present our waveguide design and calculate the optical confinement factors to estimate the modal gain and predict the threshold carrier density.
Chang
Guo-En
GE
Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Chang
Shu-Wei
SW
Chuang
Shun Lien
SL