Broadband Asymmetric Light Transport in Compact Lithium Niobate Waveguides

Asymmetric on-chip light transport is important but always challenging for photonic integrations. Although it has been recently implemented by adiabatically encircling the exceptional points in a non-Hermitian system, these approaches are fundamentally restricted to the adiabatic condition that brings disadvantages of low transmission efficiency and large device footprint. Here, it is proposed to realize a broadband asymmetric light transport in compact non-Hermitian coupled waveguides on the lithium niobate-on-insulator (LNOI) platform. The asymmetric function is fulfilled by a particular mode selection in a loss-controlled LNOI waveguide triplet, where a lossless zero mode plays a crucial role. Moreover, the shortcut to adiabaticity is applied to speed up the light evolution and shorten the device length. The approach works out a new strategy to establish an asymmetric light transport in a compact form, indicating further new on-chip light manipulations in this promising LNOI photonic platform.

Automated summary

Broadband asymmetric light transport is achieved in non-Hermitian coupled waveguide triplet on the lithium niobate-on-insulator (LNOI) platform. A particular mode selection and shortcut to adiabaticity are used to enhance transmission efficiency and reduce device length. This work opens up new possibilities for on-chip light manipulations in the LNOI photonic platform.