More than optical interconnects: employing self-written waveguides to create optical networks and multi-functional sensing elements

Abstract

Self-written waveguides (SWWs) are established as interconnection between different optical elements. They enable a rigid and easy-to-manufacture low-loss optical connection, which can be employed in many optical configurations. For the writing process, a UV-curable monomer is applied in between the two optical elements which need to be connected. If UV- or near-UV light is applied through on of the elements (i.e. fiber), the monomer starts to polymerize and increases the refractive index locally leading to a self-trapping of the beam. Subsequently, the surrounding resin can be cured with UV-flood exposure to create a rigid connection between the two components. In recent works we demonstrated that SWWs can also be used as sensing elements. Hereby, the behavior of the SWW during the heating process itself was used for measuring of changes of the temperature. Another approach is the combination of SWWs with Fe(II)triazol-complexes to detect different physical parameters such as electric and magnetic fields or temperature and humidity changes, respectively. We also investigated the implementation of thin-film filters for splitting of an SWW in multiple beams, enabling us to create a reference and sensing arm for versatily measurement applications.