Controllable frequency conversion in the coupled time-modulated cavities with phase delay

Abstract

By introducing the phase delay in time-modulated photonic structure, the outgoing waves can acquire a dispersionless phase shift regardless of incident angle and polarization. Here, we present a mechanism to control the frequency conversion using a system of two coupled time-modulated cavities with phase delay. The frequency conversion efficiency of structure can be finely controlled by tuning the modulation phase of cavities. The asymmetric frequency conversion to a single sideband can be achieved at the reflection port of structure by changing the intercavity coupling and the modulation phase. The corresponding physical mechanisms are described by a simple three-frequency model. The controllable frequency conversion achieved by the modulation phase in the time-modulated photonic structure can significantly enhance the tunability and the possible functionalities of photonic elements.