Second-harmonic generation in 60GeS(2)-20Ga(2)S(3)-20KBr chalcohalide glass was investigated by the thermal poling method. A large second-order nonlinear susceptibility, as high as 7.0 pm/V, was obtained in a poled sample by Maker fringe analysis. We believe this to be the first time that a clear second-harmonic wave was observed in chalcohalide glasses containing large amount of alkali ions (6.25 at. %). Such observation is of great potential use in all optical waveguide devices.

Tellurite glasses exhibit attractive optical properties such as high refractive index, high transmittance in the infrared-to-visible region, and large third-order nonlinear susceptibility. Poled tellurite glasses also show second-harmonic generation (SHG) as revealed by the present authors. However, there exist many unresolved problems in second-harmonic generation of oxide glasses; SH intensity is low and it decays at room temperature. In this work, the effect of Al2O3 addition on SH intensity and its decay has been explored for thermally poled sodium tellurite glasses. The decay rate of SH intensity is reduced by the addition of Al2O3. The result is similar to those reported for phosphate and silicate glasses containing Al2O3. Also, the glasses poled at a voltage of 4 kV manifest optimum poling temperature lower than that for the same glasses poled at 3 kV.