Rahat Ullah has been working as an Associate Professor in the Institute of Physics and Optoelectronics, Nanjing University of Information Science and Technology, Nanjing, China, since April 2017. He obtained his Ph.D. degree in optical engineering from Beijing University of Posts and Telecommunications, Beijing, China, with distinctions in March 2017. Rahat Ullah is originally from Pakistan, where he worked as a Lecturer and Assistant Professor for around six years. His research interests include optical communications and networks. His email is rahat@nuist.edu.cn