Slot waveguides design for optical enhancement at 1550 nm

Abstract

Photonic integrated circuits (PICs) represent a key topic to overpass the frequency limits of the current microelectronics technologies and keep the pace of Moore’s law. Research in the field of PICs is taking a boost, especially because of its compatibility with the modern complementary metal–oxide–semiconductor (CMOS) fabrication techniques utilizing materials such as silicon and silicon dioxide. Silicon-on-insulator slot waveguides are a burgeoning platform for the sophisticated on-chip integration applications. Slot waveguides have been widely used in integrated photonic devices including on-chip optical sensors, lasers, optical amplifiers, optical splitters, optical tweezers, optical phase shifters and so on. The enhancement of electrical fields in slot waveguides is an important topic for improving the performance. In this paper, the structural optimization and parametric analysis of the slot waveguide geometry for optical enhancement and nanoscale confinement are presented at telecom wavelength of 1550 nm. Different designs of the waveguides are studied including photonic crystal slabs with air holes and slot layers made from different dielectric materials such as aluminum nitride, gallium nitride and silicon nitride. The simulation shows that, with the help of periodic air holes in slabs, and by using nitrides in slot regions, the field confinement factor is significantly increased. Our study might be helpful for the design of high efficient subwavelength optical devices which may have great applications in optical computing studies.