Controllable Surface Plasmon Polariton Propagation Length Using a Suitable Quantum Dot Material

The hybrid surface plasmon polariton waveguide (HSPPWG) can carry and manipulate optical signals in nanoscale conduits. As a type of plasmonic waveguide, the HSPPWG helps designers to increase speed and develop high-density interlayer connections in order to improve network bandwidth and data transmission rates for future optical communication networks. The HSPPWG is a versatile photonics and integrated optics platform because of its unique characteristics. To achieve high efficiency, the quantum dot (QD) was used in the proposed structure and simulated it with the COMSOL Multiphysics software together with MATLAB. The main objective of the study is to increase the propagation length compared to conventional structure (without QD) while maintaining good quantitative confinement according to the figure of merit (FoM) test and confinement factor. We show that the confinement factor (Γ) at n_2D of 17.8 × 10¹⁰ cm⁻² and QDisk of 3 nm height provides superior confinement compared to QDisk heights 2 nm and 4 nm. The figure of merit at 1550 nm is approximately 105, outperforming the FoM value in the traditional case without quantum dots. The FoM at most wavelengths exceeds that of the traditional state. The propagation length (L_p) values at a QDisk height of 3 nm are 38 µm and 32 μm at 1550 nm and 1300 nm, respectively. The L_p of the SPP in the HSPPWG did not show a significant increase at wavelengths 1300 nm and 1550 nm. Therefore, we replaced the used InP semiconductors with other semiconductor materials such as AlGaAs. The L_p at the wavelength of 1550 nm reached 67.7 μm at a refractive index of 3.0238.