Investigation of sub-diffraction mode characteristics in a semiconductor plasmonic nanolaser at telecom wavelength

Nanolasers are the key component in photonic integration and in this work we investigate the mode characteristics of an optically pumped Metal-Insulator-Semiconductor (MIS) plasmonic nanolaser structure at the sub-diffraction limit. The nanolaser structure consists of Ag/oxide/InGaAsP materials and operates at the telecom wavelength of 1330 nm. For two different oxides (Al₂O₃, MgF₂) and waveguide sizes, mode-characteristic parameters such as effective refractive index, propagation loss, mode area and confinement factor are calculated. In addition, the threshold gain for each mode is investigated and the appropriate waveguide size according to the required threshold gain is estimated. Based on our calculations, the hybrid mode can propagate with low loss and sub-diffraction size in waveguides of 650 to 800 nm width.