Debris-reduced laser machining of polymeric waveguides for optoelectronic applications

A polymer multilayer was spin coated on a substrate and was structured with pulsed KrF-excimer laser radiation to generate optical waveguides. Ablation rate, surface roughness and wall-angles were determined using white light interferometry, atomic force microscopy and light microscopy. Polymeric waveguides can be used for optical transmission and their properties such as mode propagation and absorption losses were determined with beam diagnosis. However, compared to other structuring techniques absorption losses of the waveguides are high. One reason for this is the formation of debris on the surface of the waveguides during the process of structuring. Therefore, an investigation of the distribution of debris during structuring was conducted. Different types of processing gases and pressures were used to decide which configuration provides a minimum amount of debris. Absorption losses were again determined and successfully decreased after debris reducing strategies were applied.