Tunable and efficient near-infrared plasmonic interconnect circuit based on an index matching layer and a metal reflector

The plasmonic interconnect circuit (PIC) has shown great application prospects in chip-level optoelectronic systems. In this paper, we focus on a class of on-chip PIC based on a subwavelength metal grating coupler and decoupler. We systematically study the effect of grating depth on the coupling and decoupling efficiency of the designed device. The energy utilization of the device can be greatly improved and the device footprint has been reduced by about 30% at the same time by using an index matching layer. The optimal operating point of the device is finally stabilized around 1310 nm by adjusting the refractive index of the top matching layer and introducing the bottom metal reflector. The coupling and decoupling efficiency of the optimized device can reach 38% and 18% respectively and can be future adjusted linearly and synchronously by changing the refractive index of the matching layer. Our work provides an efficient and easily-fabricated PIC platform and gives the possibility to realize tunable on-chip plasmonic interconnection. (c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement