Bragg gratings made with ultrafast radiation in non-silica glasses; fluoride, phosphate, borosilicate and chalcogenide Bragg gratings

In this paper, we present results of Bragg grating inscription in optical waveguide glasses other than those based on fused silica, using the femtosecond infrared (IR) laser inscription of Bragg gratings method that is based on the mechanism of multiphoton ionization and plasma absorption. This mechanism allows for the inscription of Bragg grating structures not only in the fused-silica glasses without Ge-doping but also in other glasses such as fluoride, phosphate, chalcogenide and borosilicate which are important optical substrates for applications as mid IR fiber lasers and sensing. The writing method, spectral characteristics, polarization properties and thermal stability of the Bragg gratings are discussed.