Comparison of bending losses in integrated optical circuits.

We present measured losses in waveguide sections that are caused by connecting two parallel noncollinear straight waveguides and compare the results with theory. Two different offset transitions are considered, one composed of a straight section with sharp corner bends and the other exhibiting a smooth S-shaped transition. These two types of transitions are compared with each other to determine when each has the lowest loss. In general, sharp corner bends are preferred for small offsets, whereas larger offsets exhibit lower loss with the S-bend design. The experimental results were measured for 3-microm-wide Ti-diffused LiNbO 3 single-mode waveguides.