Fully Reconfigurable Fano Resonator on a Silicon Photonic Chip

A fully reconfigurable Fano resonator on a silicon photonic chip is reported. The Fano resonator is realized with the use of an add-drop micro-disk resonator (MDR) and a Mach-Zehnder interferometer (MZI). The waveguides at the through and drop ports of the MDR connect to two spiral waveguide arms of the MZI directly. Two independent metallic micro-heaters are incorporated on top of the MDR and the lower arm of the MZI. Thanks to the resonant mode interference between the MDR and the MZI, the Fano resonance occurs. By thermal tuning the resonance coupling between the MDR and the MZI, the generated Fano resonance is fully tunable. In addition to the independent tunable slope rate (SR) and the resonance wavelength, the Fano resonance wavelength can shift while its line shape remains by simultaneously controlling the two micro-heaters. A chip is designed, fabricated and evaluated. The measurement results show that the static Fano resonance has a line shape with an extinction ratio (ER) of 17.1 dB and SR of -13.6 dB/nm. By simultaneously controlling the two micro-heaters, full reconfigurability of the Fano resonance is demonstrated. Thanks to its straightforward configuration, the proposed Fano resonator holds the key advantage in terms of ultra-compactness and fully reconfigurability, which offers a great potential for applications such as on-chip optical switching, modulation and microwave photonics applications.