All-optical switching in epsilon-near-zero asymmetric directional coupler

We propose an all-optical switch based on an asymmetric directional coupler structure with epsilon-near-zero (ENZ) layer. The nonlinear optical properties the of ENZ layer are analyzed by hot-electron dynamics process, and the all-optical operating performance of the switch on the silicon nitride platform is investigated. It is found that the pump-induced refractive index change in ENZ layer gives rise to a transfer of signal light in the optical system. We demonstrate that the proposed switch design features an insertion loss of < 2.7 dB, low crosstalk of < - 18.93 dB, and sub-pico-second response time at the communication wavelength of 1.55 mu m. With ultrafast response, high performance, and simple structure, the device provides new possibilities for all-optical communication and signal processing.

Automated summary

An all-optical switch based on an asymmetric directional coupler structure with an epsilon-near-zero (ENZ) layer is proposed and investigated. The nonlinear optical properties of the ENZ layer are analyzed through the process of hot-electron dynamics, and the switch's performance on the silicon nitride platform is studied. It is found that the refractive index change in the ENZ layer induced by the pump leads to the transfer of signal light in the optical system. The proposed switch design exhibits low insertion loss, low crosstalk, and sub-pico-second response time, providing new possibilities for all-optical communication and signal processing.