Parity-Time Symmetric Coupled Microresonators with a Dispersive Gain/Loss

TL;DR

This paper investigates PT-symmetric coupled microresonators with realistic material models, analyzing how dispersion, frequency misalignment, and gain/loss imbalance affect their PT symmetry breaking and performance.

Contribution

It provides a detailed analysis of PT-symmetric whispering gallery resonators considering realistic dispersion and practical scenarios, highlighting how to optimize PT properties.

Findings

Dispersion causes skewness in frequency bifurcation.

Frequency misalignment reduces the PT breaking point.

Gain/loss imbalance can compensate for inherent losses.

Abstract

The paper reports on the coupling of Parity-Time (PT)-symmetric whispering gallery resonators with realistic material and gain/loss models. Response of the PT system is analyzed for the case of low and high material and gain dispersion, and also for two practical scenarios when the pump frequency is not aligned with the resonant frequency of the desired whispering gallery mode and when there is imbalance in the gain/loss profile. The results show that the presence of dispersion and frequency misalignment causes skewness in frequency bifurcation and significant reduction of the PT breaking point, respectively. Finally, as coupled WGM resonators are inherently lossy structures, we show that unbalancing the gain/loss in resonators is required to compensate for inherent loss of the structure and achieve improved PT properties.