Low transition losses in bent rib waveguides

Ultracompact Silicon Waveguide Bends Designed Using a Particle Swarm Optimization Algorithm

“…A wide variety of approaches have been developed to reduce the total bending loss of a waveguide bend. For example, mode mismatch loss at the interfaces (the straight-to-bend joints) can be reduced by using taper structures [6] or offsetting the position of straight waveguides such that the positions of mode profiles with maximum power distribution of the straight and bent waveguides are aligned [7][8][9]. In [10], compared with the circular waveguide bend, the authors show that the optimal waveguide bend has larger radius of curvature at the two ends for a better mode matching with straight waveguides.…”

Core depth determination of a slightly buried Si-wire waveguide with a reduced bend loss

“…In a buried silica waveguide, we have proposed a simple technique to reduce the total bend loss, 14) in which only the distance between the core and the air-cladding interface is adjusted. The proposed technique has the advantage that an additional technique, such as offsetting the core axis, 12,[15][16][17] can readily be combined to further reduce the transition loss. Recently, we have applied our technique to a bent Si-wire waveguide, and found the possibility of reducing the bend loss in a specific waveguide with a square-shaped core.…”