On-Chip Fabrication-Tolerant Exceptional Points Based on Dual Scatterer Engineering
The intriguing and anomalous optical characteristics of exceptional points (EPs) in optical resonators haveattracted signifcant attention. While EP-related phenomena havebeen observed by perturbing resonators with off-chip componentsimplementing EPs fully on-chip remains challenging due to theirextreme susceptibility to fabrication errors. In this Letter, we propose a succinct and compact approach to reach EP in an on-chip integrated silicon microring resonator by manipulating the evolution of backscatterings with two nanocylinders of disparate diameters. The theoretical analysis unveils that the fabrication constraints could be signifcantly relieved by increasing thediference in diameters of the nanocylinders. The evolution fromnon-EP to EP is traced experimentally through the step-by-step tuning of the angular and radial positions of nanocylinders. The proposed method opens a pathway toward the on-chip high-density integration of non-Hermitian devices.
