Thermo-optic properties of sol-gel-fabricated organic–inorganic hybrid waveguides

Organic/inorganic hybrid glass waveguides were fabricated by the sol-gel technique followed by direct ultraviolet patterning. The thermo-optic coefficient $\mathrm{(dn/dT)}$ of the hybrid material was measured by a prism-coupling method and was found to be ${\text{−1.44×10}}^{\text{−4}}\mathrm{/°}\mathrm{C},$ comparable to those of typical polymer materials. In order to investigate the possibility of using this hybrid glass material as a thermo-optic waveguide material, a $\text{2×2}$ Mach–Zehnder interferometric optical switch was fabricated on a silicon wafer. At the wavelength of 1.55 μm, the switch response time was measured to be less than 4.2 ms, and the switching power was 9.3 mW. Experimental results show that this hybrid material is very suitable for application in integrated thermo-optic components.