Vol. 51, Issue 1, pp. 75-85
germanate glass, ultrafast waveguide writing, near-infrared laser operation, high linear and nonlinear refractive index
A stable composition (against crystallization) of germanate glass doped with Yb3+ for mid-infrared laser applications is presented. Broad emission spectrum of Yb3+ was obtained for the fabricated glass. Laser operation was demonstrated in 13 mm long waveguide written in the glass using a femtosecond laser operating at 524 nm center wavelength sending 250 fs ultrashort pulses. The resulting CW laser operated at 1.04 µm in the fundamental mode of the waveguide. The propagation loss through the waveguide was 0.6 dB/cm at 1550 nm for 45 µm diameter of the modified structure. The mode analysis of the developed waveguide structure is also presented in COMSOL Multiphysics to study the electric field distribution through different modes of propagation in the waveguide and the confinement loss associated to them.