Heat-induced multimode interference variable optical attenuator based on novel organic-inorganic hybrid materials

A heat-induced multimode interference (MMI) variable optical attenuator at 1310 nm wavelength, based on novel organic–inorganic hybrid materials is successfully designed and fabricated. The thermal stability and optical properties of the sol–gel materials are analyzed. The thermo-optic (TO) coefficient of the organic–inorganic hybrid material is obtained as −1.85 × 10⁻⁴ °C⁻¹. The characteristic parameters of the waveguides and heat-induced electrodes are carefully designed and simulated. The propagation loss of a 4 μm-wide straight waveguide is 0.56 dB cm⁻¹. The attenuation of the device is about −25 dB, and the applied electric power is 36.2 mW. The new material system and low-cost fabrication technique could be suitable for realizing large-scale photonic integrated circuits. (paper)