10.6084/m9.figshare.7642253.v1 Yuan Yu Yuan Yu PT-symmetry OEO.mp4 Optica Publishing Group 2019 Microwave and RF Photonics 2019-07-23 15:33:50 Media https://opticapublishing.figshare.com/articles/media/PT-symmetry_OEO_mp4/7642253 A stable 17.74-GHz microwave signal generated by the OEO with selective PT-symmetry breaking .