Transmission characteristics of multi-structure bandgap for lithium niobate integrated photonic crystal and waveguide

Abstract

As one of the basic components of integrated optics, optical waveguide with the characteristics of low loss and high integration has received more and more attention recently. In this paper we proposed a new optical waveguide structure with high transmission rate based on Lithium Niobate integrated two-dimensional (2D) photonic crystal. The structural modeling and band gap analysis to four kinds of two-dimensional photonic crystals with lithium niobate are carried out by using the plane wave expansion (PWE) method. Compared to the other three structures, the triangular lattice structure of the photonic crystal has a wider infrared band electromagnetic band gap. The dielectric column structure (a=697 nm and r/a=0.228) has a complete TE photonic band gap (PBG) of 1285 nm to 1768 nm, while the air holes column structure ( a=628 nm and r/a=0.351) has a complete TM PBG of 1372 to 1807 nm. The finite difference time domain (FDTD) method is used to simulate the transmission characteristics of the two structures with line defect. By adjusting and optimizing the line defect structure, the transmission rate of the curved waveguide of the two structures is increased by more than 90%, which is of great significance to the study of all-optical integrated networks.