An arrangement for providing optical crossovers between waveguides formed in an SOI-based structure utilize a patterned geometry in the SOI structure that is selected to reduce the effects of crosstalk in the area where the signals overlap. Preferably, the optical signals are fixed to propagate along orthogonal directions (or are of different wavelengths) to minimize the effects of crosstalk. The geometry of the SOI structure is patterned to include predetermined tapers and/or reflecting surfaces to direct/shape the propagating optical signals. The patterned waveguide regions within the optical crossover region may be formed to include overlying polysilicon segments to further shape the propagating beams and improve the coupling efficiency of the crossover arrangement.