Differential all-optical tuning of eigenmodes in coupled microdisks

A differential all-optical resonance tuning of whispering-gallery-modes (WGMs) in a system of three coupled microdisks in a line arrangement is investigated. Utilizing the temperature induced nonlinear effects observable in coupled WGM microresonators, a tunable, narrow bandwidth, three-wavelength filter is demonstrated. Variable tuning scenarios for the signal resonances are achieved at the same sample, depending on the coupling conditions of the control signal at low control powers of up to 4 mW only.