Non-Hermitian gauged topological laser with multi protected modes

Abstract

A topological laser array based on the non-Hermitian Su-Schrieffer-Heeger chain of coupled microring resonators has been presented in this manuscript. Based on the theory of the active and passive microrings in each unit cell, we have defined a PT-symmetry structure where the edge states can be protected and the imaginary gauge field cause delocalize light between the microrings. Numerical simulations based on the rate equation model and stability analysis have been performed to demonstrate the stability criteria of the presented structure. Utilizing this configuration, it has been shown that the number of protected topological supermodes can be controlled by the number of active and passive microrings in each unit cell while all the other extended supermodes are transformed into the non-topological states. Design flexibility to expand and modify the lasing stability region and topological supermode selection can be obtained based on the introduced configuration.