“…Therefore, 1.55 ÎŒm InP-based quantum dash lasers were reported by many research groups [ 42 , 43 , 44 ]. The study of QDs is continuing on the epitaxy growth, the design, and the fabrication to improve the performance of the QD devices [ 45 , 46 ]. The review is organized as follows: in Section 2 , two main growth methods of QD structures, including top-down and bottom-up approaches are briefly described; in Section 3 , the physics and device performance of QDs, including the modal gain, linewidth enhancement factor, temperature dependent optical properties, carrier dynamics of QD materials, low threshold current density, high temperature insensitivity, modulation characteristics, and high optical feedback tolerance of QD devices, are discussed; in Section 4 , the active and passive QD-based laser devices in the context of fiber-optic communication, including FabryâPerot (FâP) lasers, Distributed Feedback (DFB) lasers, Vertical-Cavity Surface-emitting lasers (VCSELs) and SESAM mode-locked lasers are reviewed.…”