Effect of additional layers on bend loss in buried channel waveguides

The authors propose a new strategy to increase or decrease bend loss in single-mode buried channel waveguides in a predictable manner. This strategy is based on the presence in the cladding of additional layers with different refractive indices on either or both sides of the core in the plane of the bend. It is demonstrated that this approach can lead to significant bend loss reduction when compared to other strategies, and, conversely, can be used to enhance bend loss for a fixed bend radius for application to devices such as optical attenuators.