Ultra-Compact and Ultra-Broadband Mode (De)Multiplexer Utilizing an Asymmetrical Coupler with SWG and Cascaded Tapered Waveguide

A 25 μm two-mode (de)multiplexer on a silicon-on-insulator platform is demonstrated. Operating in 200 nm bandwidth, it achieves low insertion-loss (< 0.9 dB), minimal crosstalk (< 18.8 dB), and clear eye diagrams at 64 Gbit/s.