Polarization Control and TM-Pass Filtering in SiN Photonics Integrated With 2D Multiferroic Materials

Polarization control is a critical function in integrated photonic circuits, directly impacting performance, stability, and signal integrity. In this work, we demonstrate the integration of multiferroic two-dimensional (2D) material CuCrP₂S₆ (CCPS) with silicon nitride (SiN) photonic devices to achieve polarization-selective filtering and rotation. Our experimental results show that microring resonators incorporating CCPS exhibit transverse magnetic (TM)-pass filtering with a polarization extinction ratio exceeding 25 dB and a low insertion loss of ∼ 0.2- 0.4 dB at 1500 -1600 nm. Additionally, under TM-mode input, straight waveguides loaded with CCPS can achieve a significant polarization rotation, with azimuth angle shifts reaching up to 92.9°. Simulations and experimental validation indicate that the primary mechanism behind these effects is the polarization-dependent optical mode overlap. This overlap is governed by the refractive index profile of the CCPS/SiN hybrid system and the waveguide's geometrical dimensions. The anisotropic properties of CCPS provide further enhancement but play a secondary role. These results highlight the potential of CCPS-integrated devices for compact, high-performance polarization control in on-chip photonic platforms.