Berry Phase and Adiabatic Breakdown in Optical Modulator

We consider an all in-fiber optical modulator based on a ring resonator configuration. The case of adiabatic to nonadiabatic transition is considered, where the geometrical (Berry) phase acquired in a round trip along the ring changes abruptly by pi. Degradation of the responsivity of the modulator due to finite linewidth of the optical input is discussed. We show that the responsivity of the proposed modulator can be significantly enhanced with optimum design and compare with other configurations.