Preface This is an annual report on the research activities in the field of optical communications and high-speed electron devices for 1998 at the Faculty of Engineering and Research Center for Quantum Effect Electronics, Tokyo Institute of Technology. 　 These activities are initiated by Professor Y. Suematsu (emeritus, the former president), and Professor S. Arai [Group A], mainly in the field of Semiconductor Photonic Devices including Low-dimensional Quantum-well Lasers, Photonic Switching Devices, and also in the fabrication of ultra-fine structures; 　 This report consists of a brief introduction of the research activities and a collection of the research papers published in 1998.