Fig. 1. Experimental setup for measuring optical propagation loss

Fig. 2. Observation of thin film surface under optical microscope and SEM

Fig. 3. XRD spectra of the films

Fig. 4. Photoluminescence spectra of the films deposited under different conditions

Fig. 5. Structure diagrams and optical field distributions in the different waveguide

Fig. 6. Cross-section SEM images of the waveguide

Fig. 7. Transmission loss of waveguide at 1.31 μm