Exceptional point shifted by Kerr effect in anti-parity-time symmetry system

Abstract

With respect to parity-time symmetry, an anti-parity-time (APT) symmetric system exhibits much easier readout mechanism due to its real frequency splitting. Generally, such systems need to be operated at exceptional points (EPs) to obtain the best performance. However, strict conditions to locate APT symmetric systems at their EPs precisely put restraints on their practical applications. To overcome this problem, we propose a scheme to manipulate EPs in APT symmetric configuration by the Kerr effect. It is demonstrated that operating EPs by self-phase modulation alone will impede frequency splitting caused by external perturbations, while cross-phase modulation can enhance the response to measurable perturbations. We also investigate the thermal effect induced by high light intensity, which could reduce the power to manipulate EPs. This proposed scheme can pave a new way for fabricating devices based on APT symmetry.