Electrically Tunable Fano Resonance Line Shapes by Using Racetrack Microresonator-Coupled Mach-Zehnder Interferometers with Embedded p-i-n Diodes

We report our initial experimental demonstration of electrically tunable Fano resonance line shapes by using racetrack ring microresonator-coupled Mach-Zehnder interferometers with embedded p-i-n diodes on silicon-on-insulator substrates. Fano resonance observed at the interferometer output ports is due to interference between the guided lightwave that is coupled to the microresonator and the coherent lightwave guided in the interferometer reference arm. We apply a relative phase shift to the interferometer reference arm by current injection, thereby electrically tuning the Fano resonance line shape through free carrier plasma dispersion effect. Our initial experiments reveal different characteristic sharp asymmetrical resonance line shapes upon application of less than IV forward biases across the embedded p-i-n diode