Design Considerations for Single-Mode Microring Lasers Using Parity-Time-Symmetry

Coupled microring arrangements with balanced gain and loss, also known as parity-time symmetric systems, are investigated both analytically and experimentally. In these configurations, stable single-mode lasing can be achieved at pump powers well above threshold. This self-adaptive mode management technique is broadband and robust to small fabrication imperfections. The results presented in this paper provide a new avenue in designing mode selective chip-scale in-plane semiconductor lasers by utilizing the complex dynamics of coupled gain/loss cavities.