Abstract

Vertical-cavity surface-emitting lasers (VCSELs) have much attractive low-cost, high-performance light sources for various applications including local area networks, fiber-optic communication systems, data storage, optical computing and different sensors. Currently, the oxide-confined VCSEL has been the most promising structure, wherein the current apertures obtained by selective oxidation technique for index-guiding and current confinement resulting reduce the optical losses and current spreading. However, in case of small-sized VCSELs with quantum well active region, the carrier leakage due to lateral diffusion increases the threshold current and decreases the differential efficiency. Using of self-assembled quantum dots (QD) as an active material of semiconductor lasers can overcome this problem [1], There are two major methods to grow self-assembled QDs, one is Stranski-Krastanov (SK) growth and the other is sub-monolayer (SML) growth. The major challenge for SK grown QD VCSELs is significantly lower material gain (up to 10 cm'¹ per one SK QD layer) caused by large inhomogeneous broadening and low surface density of QD arrays [2], However, the SML QDs exhibited much better uniformity and achieve narrower gain spectrum, higher differential gain and lower threshold current density when used as an active medium of a diode laser [3], In this paper, we present the temperature dependent perfonnance of VCSELs based on SML InGaAs QDs with fully doped AlGaAs/GaAs DBRs and the SML QD VCSEL shows extremely temperature insensitivity under high speed operated in 2.125 Gb/s from−40°C~100°C

© 2007 IEEE