Femtosecond-Laser Fabrication of Waveguides in Laser Materials

This proposal includes, for the first time, integrated theoretical models and experimental investigations to simulate and demonstrate femtosecond-laser-fabricated waveguides in crystalline dielectric materials. The numerical models will predict refractive-index changes potentially induced by self-focusing, heat accumulation, thermal stress, plasma formation and relaxation, and ablation. The influence of focal conditions and laser parameters (pulse energy, wavelength, repetition rate, focal spot size, and scanning speed) on waveguide quality and geometry will be theoretically and experimentally investigated via sensitivity studies. The index modulation will be evaluated for the three major waveguide-design configurations (Type I, II, and III) using matrices of laser parameters. The effectiveness of the three types of waveguide configurations will be compared for laser materials. To prepare for Phase II, the technical feasibility of producing waveguide lasers will be accessed through numerical modeling. Concepts for developing a waveguide laser will be identified. This innovation will enable the fabrication of low-loss optical waveguides for integrated photonic circuits with the integrated active and passive devices on the micron scale. It will provide weight, power and cost reductions for tele-communications, advanced data centers, and free-space communications. The femtosecond-laser-enabled compact three-dimensional waveguides and waveguide-laser sources provide a unique platform for versatile photonic applications to remote sensing, analog RF, quantum computing and biomedical monitoring, and others.