Wavelength-insensitive and Lossless 50:50 Directional Coupler Based on Silicon Bent Waveguides

A broadband 50:50 bent directional coupler, based on low loss bends, is experimentally demonstrated to significantly reduce coupling variation from 0.369 in the traditional directional coupler to just 0.076 over an 80 nm wavelength range, showcasing a substantial 4.85 times less coupling variation.