Ultrafast laser processing: New options for three-dimensional photonic structures

During the past years ultrashort pulse lasers have gained a lot of interest for the direct writing of photonic structures in transparent media. This technique allows to produce true three-dimensional optical structures and is applicable to many different glasses as well as to crystalline media. Although the mechanism responsible for the refractive index changes is still under discussion, various photonic structures, ranging from low loss optical waveguides to couplers, three-dimensional splitters and also active waveguides, have been realized. In this presentation, an overview of the recent advances in the ultrafast direct writing of photonic devices in different glasses as well as crystalline media will be given.