Design and characterization of a mode-splitting /spl Psi/-junction

It will he shown In this paper, that the mode conversion factor (MCF) as defined for Y-junctions, can be profitably applied for the design of three branch junctions for splitting the three lowest-order modes of a channel waveguide. Accordingly, these so-called mode-splitting /spl Psi/-junctions were designed for implementation in PECVD SiON-technology. Propagation calculations point to crosstalk levels well below -20 dB at 10-20 mm junction length. The produced /spl Psi/-junctions show crosstalk of less than -17 dB, mainly originating from the nonhomogeneity of the refractive indexes of the SiON layers.