Three-dimensional integration of passive functions on glass by means of selectively buried waveguides and multiple ion-exchanges

Ion-exchange on glass has been successfully used for more than twenty years to realize integrated optics devices such as wavelength multiplexers, splitters, optical amplifiers, lasers or sensors. One of the major issue is today to integrate more functions on a single chip which is usually realized be reducing the dimensions of the waveguides. Nonetheless this reduction is intrinsically limited by the maximum index variation achievable. For this reason, we propose and investigate in this article the realization of 3D structures where waveguides are integrated vertically instead of horizontally. Based on the selective burial of ion-exchanged waveguides and the cascading of multiple ion-exchanges, the realization of "vertical" asymmetric and symmetric Y-junctions have been investigated theoretically.