High Efficiency Ring-Resonator Filter With NiSi Heater

We demonstrate a high efficiency tunable ring-resonator filter on the silicon-on-insulator platform. The fabricated device shows the characteristics of a low power consumption and an ultrafast temperature-rise response. The ring-resonator is based on ridge-type silicon waveguide with NiSi heater formed on the silicon slab region surrounding the ring. The heat generated from the NiSi heater is directly transferred to the ring resonator through the silicon slab layer. Meanwhile, the ring-resonator is suspended by removing the adjacent SiO₂ layer and the underlying silicon substrate. The measured temperature-rise response time is only 1.25 μs. The power consumption for 1-nm wavelength shift is only 0.38 mW, corresponding to 4.9 mW/free spectral range. The power consumption reduces 92% as compared to a similar structure without the air-isolation trench.