Reconfigurable TE-pass polarizer based on lithium niobate waveguide assisted by Ge2Sb2Te5 and silicon nitride

Abstract

On-chip polarization management components play a critical role in tackling polarization dependence in the lithium-niobate-on-insulator (LNOI) platform. In this work, we proposed a reconfigurable TE-pass polarizer based on optical phase change material (GST) and the LNOI wafer. The key region is formed by a hybrid GST–Si3N4 layer symmetrically deposited atop the centerline of the LNOI waveguide along the propagation direction where the GST is sandwiched in the middle of the Si3N4 layer. Whether the polarizer will take effect depends on the phase states of the GST layer and the graphene and aluminum oxide layers are coated atop the GST−Si3N4 layer as the microheater to control the conversion of phase states. The proposed device length is 7.5 µm with an insertion loss (IL)=0.22 dB and extinction ratio (ER)=32.8 dB at the wavelength of 1550 nm. Moreover, it also has a high ER (>25dB) and a low IL (<0.5dB) in the operating bandwidth of 200 nm. Such a high-performance TE-pass polarizer paves a new way for applications of photonics integrated circuits.