Femtosecond laser writing of optical waveguides with controllable core size in high refractive index glass

Optical waveguides have been produced by femtosecond-laser writing in a high linear and nonlinear refractive index glass (SF57). Light guiding occurs nearby a central damaged zone due to the collateral densification caused by shockwaves generated in the focal volume. High pulse energies are required to induce a modified region capable of supporting a guided mode. An alternative processing method, based on using multiple structures, has been successfully used for the production of waveguides with controllable core size at low energies.