Design of an Ultralow Loss Silicon Plasmonic Waveguide and High-Performance Devices

Here, we propose an ultralow loss rounded top metal silicon (Si) hybrid dielectric-loaded plasmonic waveguide (RTM-SiHDLW) and two high-performance RTM-SiHDLW-based optical components: 1) a directional coupler and 2) an optical resonator. The RTM-SiHDLW adopted a relatively thick metal stripe with rounded corners for reducing Ohmic loss around stripe edge/corner. A propagation length of 0.47 mm is obtained by numerical simulation, an increase of ~30%, at a similar mode area, compared with conventional TM-SiHDLW. A RTM-SiHDLW-based directional coupler was then designed and a coupling length of 2.42 μm, ~0.69% of the propagation length, was achieved. In addition, a second RTM-SiHDLW-based device, an optical resonator, was designed to operate at the low loss TE011 mode. A metal enclosure was employed for reducing the radiation loss. Simulation results show that, a quality factor of 1807, more than twice the results in previous works, could be obtained with a comparable resonator size.