Temperature dependence of sol-gel waveguides

The temperature dependence of the effective refractive index of waveguides based on sol-gel films is analyzed with allowance for the thermooptic coefficient of the waveguide materials and the expansion coefficient of the film material. The temperature dependence of the waveguide thermooptic coefficient on the film thickness is demonstrated. The parameters of the optical waveguides with a near-zero temperature coefficient are determined in a wide temperature range. Waveguides with a low temperature coefficient of about −10−5/°C in the temperature interval 20–80°C are designed.