Improved plasmonic splitters and demultiplexers

Analytical optimizations and numerical simulations are applied to enhance power transferring through a metal–insulator–metal (MIM) plasmonic junction. Employing the quasi static approximation for subwavelength devices, we derived a pure analytical model which complies very well with the simulation results. By inserting intermediate matching sections and stub structure at the MIM junctions, various matched plasmonic junctions and devices are designed. Both methods considerably improve the transmission spectra of the structure and enhance the bandwidth. The improved T-shaped splitters and demultiplexers of 50 nm width are designed with zero reflection at 1550 nm wavelength, 18% higher efficiency and broader bandwidth. Finite-difference time-domain simulations validate numerically our analysis and optimization results.

► A pure analytical model for design of various matching sections has been derived to minimize the junction reflection. ► The transmission spectra of the plasmonic MIM structures have been enhanced more than 18%. ► Our designs have broader bandwidth compared to the previous works. ► Numerical simulations validate completely our analytical results.