High-density information transmission and waveguide integration with low crosstalk and propagation loss

Abstract

Photonic waveguides are fundamental components for photonic integrated circuits (PICs). Although a wide spectrum of nanophotonic structures, i.e., silicon waveguides and plasmonic waveguides, have been exploited for optical interconnects, these structures either can only support one polarization or they are not able to be integrated within a 1-μm scale due to strong crosstalk. The hurdle for high-density information transmission and waveguide integration is mainly the lack of a compact waveguide structure that can support different polarization states with low crosstalk. We propose and numerically demonstrate an ultralong-range waveguide that supports both transverse electric- and transverse magnetic-like polarizations. The propagation length of this waveguide is several decimeters with working bandwidths as great as 160 nm for both polarizations. In addition, this design is very compact with a small center-to-center distance of 1 μm between two adjacent waveguides while the isolation is as high as more than 69.3 dB. This waveguide is also able to guide light efficiently through a 90 deg bend with a 1-μm bending radius for both polarizations. Our work opens new perspectives for high-density waveguide integration in PICs, which would benefit various applications with limited physical space, such as on-chip information processing and sensing.