Ultra-broadband dual-polarization silicon waveguide crossing architecture for scalable multi-port operation across ITU and 2 μm MIR bands
Year: 2025
Type: preprint
Abstract: We present and experimentally demonstrate a compact, ultra-broadband, and scalable multi-port waveguide crossing architecture that supports dual-polarization operation across both the O–L communication bands and the emerging 2 μm mid-infrared (MIR) window. The design is based on a composite subwavelength grating structure and implemented on a standard 220 nm silicon-on-insulator (SOI) platform using a single-step etching process. A unified MMI-based building block enables highly compact 2×2, 3×3, and 4×4 configurations with symmetric layouts, achieving footprints as small as 14×14 μm² for the international telecommunication union (ITU) bands and 16×16 μm² at 2 μm. The 2×2 crossing demonstrates record-wide bandwidths of ~380 nm (1300–1680 nm) and ~400 nm (1760–2150 nm), with low insertion losses of <0.3 dB / <0.2 dB (TE/TM) and crosstalk below −20 dB / −30 dB across the ITU bands. Even better performance is achieved for the TE mode in the 2 μm MIR range. To the best of our knowledge, this is the first demonstration of a dual-polarization waveguide crossing with such extensive bandwidth coverage in the ITU bands and the widest reported in the 2 μm MIR regime. The proposed architecture offers a scalable, fabrication-friendly solution for next-generation high-density photonic integrated circuits with polarization- and wavelength-division multiplexing capabilities across multiple spectral domains.
Institutions: Fuzhou University, Southeast University
Language: English
Topic: Photonic and Optical Devices
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4411102799