Cost effective fabrication of waveguides for PLCs with replication in UV curable sol-gel material

A new wafer-scale replication process for fabricating buried ridge waveguides for telecom/datacom applications using an uv-curable sol-gel material is proposed. Spin coating of the core material on the replication mould is used to form the waveguide cores with a smooth thin layer. The spin parameters allow an accurate control of the thickness and homogeneity. The bottom-cladding is uv-cast between a substrate and the mould, which is covered by the spun core layer. The ridge waveguide cores are demoulded and buried under a top cladding. This process allows the stacking of several layers of waveguides on top of each other to form two-dimensional waveguide arrays. A specially adapted SUSS mask aligner is used to control the cladding thickness between individual waveguide layers and to align them. A waveguide loss comparable to lithographically fabricated waveguides has been achieved.