Electrically Pumped Single Transverse-Mode Coupled Waveguide Lasers by Parity-time (PT) Symmetry

TL;DR

This paper demonstrates a novel electrically tunable PT-symmetric coupled waveguide laser that achieves stable single transverse-mode operation through phase transition control, combining theoretical analysis and experimental validation.

Contribution

It introduces a new electrically tunable PT-symmetric design for coupled waveguide lasers enabling single mode operation, with both theoretical and experimental insights.

Findings

Successful demonstration of PT-symmetric phase transition in a laser

Achieved stable single transverse-mode operation

Electrically controlled gain and loss tuning

Abstract

We demonstrate single transverse-mode operation of broad-area coupled waveguide lasers enabled by parity-time (PT) symmetry. The PT symmetric laser operates on coupled waveguide cavities with electrically tuned gain and loss. Such counterintuitive waveguide design enables PT symmetric breaking, causing unique mode selection and ultimately enabling single mode operation. By electrically tuning the loss in the loss region of the coupled waveguide cavity, several different PT-symmetric regimes are analyzed theoretically, and the corresponding PT symmetric phase transition is demonstrated experimentally in the coupled waveguide laser.