Abstract

Writing waveguides with femtosecond laser is a very promising technique and has already proven its performance in glasses and crystals. At the same time, writing waveguides in polymers is a just developing field, and not too much work has been reported so far [1]. Polymer material can offer the potential to create low-cost and complex structures inside the volume of the material. It was demonstrated before that it is possible to make low-loss waveguides inside polymer material with a femtosecond laser by writing irradiation lines with parallel orientation with fixed gap between them [2]. The refractive index increase is induced by material compression and stress-related effects which are caused by a quickly expanding plasma core. Here we want to show different geometries of waveguides and also waveguides which are sensing the surface of the substrate and Y-splitters, which could possibly be used for applications such as sensors and lab-on-a-chip devices. When the irradiation lines form a hexagon or quadratic geometry (see Fig. 1(a) and Fig 1(b)) it leads to an increasing densification and as a result higher refractive index. As a consequence, the higher refractive index will reduce bend losses in waveguides.

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