2D MXene Based TiO₂ Integrated Optical Polarizers with High Performance

Polarization control is essential for modern optical systems. Recently, two-dimensional (2D) materials featuring highly anisotropic absorption across broad wavelength regions have emerged as a promising solution for realizing optical polarizers with operation bandwidths far exceeding those achievable using bulk materials. Despite this, existing 2D-material-based optical polarizers face critical limitations in simultaneously delivering high polarizer figures of merit (FOMs), robust power endurance, and scalable fabrication, hindering their practical deployment beyond laboratory. Here, we overcome this bottleneck by demonstrating optical polarizers through integrating 2D MXene films onto silicon photonic devices and subsequently converting them in-situ into 2D titanium dioxide (TiO₂). The 2D TiO₂ exhibits significantly improved anisotropic absorption and thermal / chemical stability compared with MXene, enabling the hybrid polarizers to achieve a record high polarizer FOM of ~17.5 (among 2D-material-coated devices) and excellent power tolerance (stable under >2 W coupled average power), together with a broad operation bandwidth (>140 nm) and a high fabrication yield (~98%). We also demonstrate microring resonator polarizers achieving high polarization extinction ratios up to ~12 dB. With outstanding overall performance and strong capability for large-scale manufacturing, these polarizers represent a solid step towards industry-ready implementations of 2D-material-based optical polarizers.