Directional coupler based on an elliptic cylindrical nanowire hybrid plasmonic waveguide

Area of Science:

• * Plasmonics and Nanophotonics
• * Integrated Optics

Background:

• * Directional couplers are fundamental components in photonic integrated circuits.
• * Conventional couplers face limitations in size and loss, hindering miniaturization.
• * Hybrid plasmonic waveguides offer enhanced light confinement and interaction.

Purpose of the Study:

• * To introduce a novel directional coupler design utilizing an elliptic cylindrical nanowire hybrid plasmonic waveguide.
• * To analyze the coupling and transmission characteristics of the proposed device.
• * To optimize the coupler for enhanced performance in terms of energy transfer and loss.

Main Methods:

• * Employed the finite element method (FEM) for electromagnetic field analysis.
• * Simulated and compared electric field distributions of y-polarized modes.
• * Analyzed coupling and transmission characteristics to determine optimal waveguide separation.

Main Results:

• * Optimized waveguide separation distance achieved at 100 nm.
• * Demonstrated weak coupling regime with a short coupling length of 1.646 μm.
• * Achieved low propagation loss of 0.076 dB/μm and maximum energy transfer of 80%.

Conclusions:

• * The proposed elliptic cylindrical nanowire hybrid plasmonic waveguide directional coupler exhibits excellent performance.
• * Features include good energy confinement, ultracompact size, and low propagation loss.
• * Potential applications in dense photonic-integrated circuits and advanced photonic devices.