Germanium laser with a hybrid surface plasmon mode

The possibility of creating an $n^{++}$-Ge laser with a hybrid surface plasmon TM mode is theoretically studied. The distribution of electromagnetic fields and the absorbance in the mode under study, the optical confinement factor, the gain, and the threshold current density in the laser under consideration are calculated. It is shown that the threshold current density at optimal layer thicknesses of an $n^{++}$-Ge laser with a hybrid surface plasmon TM mode can be 2–3 times lower than the experimentally observed threshold current density in an $n^{++}$-Ge laser with a conventional dielectric waveguide.