Multi-frequency non-reciprocal optical directional amplifier realized with non-Hermitian resonator arrays

For a multi-frequency non-reciprocal optical device, we first realize multi-frequency optical non-reciprocal transmission using a non-Hermitian multi-mode resonator array. Practically, multi-frequency operation can add channels to the non-reciprocal optical device and the non-reciprocity can route optical signals and prevent the reverse flow of noise. Using the Scully–Lamb model and gain saturation effect, we accomplish dual-frequency non-reciprocal transmission by introducing nonlinearity into a linear array of four-mode resonators. The accomplishment is directly demonstrated by the non-reciprocal transmission phenomena present in the non-divergent peaks. For example, a directional cyclic amplifier is constructed with non-reciprocal units. Regarding potential applications, non-reciprocal optical systems can be employed in dual-frequency control, parallel information processing, photonic integrated circuits, optical devices and so on.