Tunable Fano resonance with a high slope rate in a microring-resonator-coupled Mach-Zehnder interferometer.

Fano resonance has important applications in high-sensitivity sensing, optical switching, and modulating. A tunable Fano resonance with a high extinction ratio (ER) and slope rate (SR) is in great demand. Here we demonstrate Fano resonance in a microring-resonator-coupled Mach-Zehnder interferometer that is fabricated in silicon-on-insulator. The SR and resonant wavelength of the Fano resonance can be electrically and independently tuned. In the experiment, the Fano resonance shows a maximal ER of 56.8 dB and a maximal SR of 3388.1 dB/nm. The SR and resonant wavelength also can be tuned from 870.06 to 3388.1 dB/nm, and 1558.73 to 1559.96 nm, respectively.