Ultra-Broadband, Compact Arbitrary-Ratio Multimode Power Splitter Based on Tilted Subwavelength Gratings

Mode division multiplexing (MDM) technology is an effective solution for high-capacity optical interconnection, and multimode power splitters, as essential components in MDM systems, have attracted widespread attention. However, supporting a wide range of modes and arbitrary power splitting ratios with large bandwidth in power splitters remains a significant challenge. In this paper, we designed a power splitter based on a subwavelength grating (SWG) structure with tilted placement on a silicon-on-insulator (SOI) substrate. We achieve arbitrary TE0-TE9 mode-insensitive power distribution by altering the filling coefficient of the SWG. Thanks to our specific selection of cladding materials and compensatory design for the optical wave transmission and reflection shifts induced by SWG, our device demonstrates low additional loss (EL < 1.1 dB) and inter-mode crosstalk (-18.8 < CT < -60 dB) for optical modes ranging from TE0 to TE9, covering a wavelength range from 1200 nm to 1700 nm. Furthermore, our proposed device can be easily extended to higher-order modes with little loss of device performance, offering significant potential in MDM platforms.