Apexes-linked circle gratings for low-loss waveguide bends

A low-loss waveguide bend with two apexes-linked circle gratings based on t he concept of multiple phase compensation is designed. The apexes-linked ci rcle gratings not only compensate the phase-difference in the bend corner, but also avoid distorting the eigenmode, Simulation results predict that th e phase front of the modal field can be tilted correctly in the wide-angle waveguide bend. The transmitted power efficiency can be as high as 89% for bending angle up to 10 degrees.