  Monolithic integration of quantum dot (QD) gain materials onto Si photonic
platforms via direct epitaxial growth is a promising solution for on-chip light
sources. Recent developments have demonstrated superior device reliability in
blanket hetero-epitaxy of III-V devices on Si at elevated temperatures. Yet,
thick, defect management epi designs prevent vertical light coupling from the
gain region to the Si-on-Insulator (SOI) waveguides. Here, we demonstrate the
first electrically pumped QD lasers grown on a 300 mm patterned (001) Si wafer
with a butt-coupled configuration by molecular beam epitaxy (MBE). Unique
growth and fabrication challenges imposed by the template architecture have
been resolved, contributing to continuous wave lasing to 60 {\deg}C and a
maximum double-side output power of 126.6 mW at 20 {\deg}C with a double-side
wall plug efficiency of 8.6%. The potential for robust on-chip laser operation
and efficient low-loss light coupling to Si photonic circuits makes this
heteroepitaxial integration platform on Si promising for scalable and low-cost
mass production.
