Experimental Investigations of Optical Nonlinearities in Semiconductor‐Doped Glass Waveguides

Both, thermal and electronic optical nonlinearities are studied in semiconductor‐doped glass (SDG) waveguides which are fabricated in commercially available sharp‐cut filters by Cs+–K+ ion exchange. The relaxation time in photodarkened substrates is measured to be 30 ps. By means of a prism coupling set‐up the saturation value of the nonlinear index change is determined. Furthermore, a high stability dual‐beam interferometer is presented for the measurement of both, thermal and electronic nonlinear refractive index n2 in planar waveguides. Conclusions about the application of SDG to opto‐optical switching are given.