Fig. 1. Single mode ridge waveguide and its transmission loss test. (a) Cross-section of ridge waveguide and its mode-field intensity distribution; (b) different methods of combining materials with waveguides; (c) waveguide transmission loss test

Fig. 2. Distributions of optical field intensity at waveguide plane and cross-section for waveguides covered by aGST in different methods (@1550 nm)

Fig. 3. Optical transmission transmittance of waveguides with materials attached in different ways

Fig. 4. Runway micro-ring resonance structure and resonant optical field in the ring with GST attached in full coverage mode on different areas. (a) Schematic of runway micro-ring resonance structure; (b) straight waveguide; (c) curved waveguide

Fig. 5. Spectra inside the micro-ring after the straight waveguide of the micro-ring is covered by materials

Fig. 6. Spectra inside the micro-ring after the bent waveguide of the micro-ring is covered by materials

Fig. 7. Spectra inside the micro-ring after filling the trench of the waveguide with SiO₂ and attaching phase change material on the top surface

Fig. 8. Optical photographs of the waveguide covered with phase change material. (a) Substrate A; (b) substrate B

Fig. 9. Spectra of waveguides in substrate A and substrate B. (a) Spectra of reference straight waveguides before and after annealing; (b) spectra of two waveguide devices covered with GST material, when GST is in amorphous and crystalline state