Reconfigurable TE-pass polarizer based on lithium niobate waveguide assisted by Ge<sub>2</sub>Sb<sub>2</sub>Te<sub>5</sub> and silicon nitride
Yedeng Fei, Yin Xu, Yue Dong, Bo Zhang, Yi Ni
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–Si 3 N 4 layer symmetrically deposited atop the centerline of the LNOI waveguide along the propagation direction where the GST is sandwiched in the middle of the Si 3 N 4 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−Si 3 N 4 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.