With the increasing scale of integration, resulting in a higher on-chi
p complexity, waveguide crossings with good performance are becoming i
ncreasingly important. Worst-case paths contain a high number of cross
ings, depending on the number of channels being processed, in switchin
g matrices [1], multiwavelength add drop filters [2] (up to 15), and o
ptical cross-connects [3]. Crossings with very low crosstalk and loss
can be realized in fiber-matched waveguide structures as used in lithi
um niobate or silica-based technology [4, 5]. In highly integrated sem
iconductor devices, crossings may contribute significantly to the loss
and crosstalk performance. In this paper we present the results of a
series of experiments for the design of high-performance semiconductor
waveguide crossings.