Sub-50 kHz Linewidth $1.55\ \mu \mathrm{m}$ Quantum Dot Distributed Feedback Lasers

Further optimized high-quality InP-based quantum dot materials with low inhomogeneous linewidth broadening were used to realize
$1.55\ \mu \mathrm{m}$
quantum dot distributed feedback lasers, which clearly show fundamental advantages in comparison to quantum well based devices in terms of new record values in emission linewidth
$(< 50\ \mathrm{kHz})$
, high output powers (
$> 17$
dBm at 20 °C) and high temperature stability (
$< 100$
kHz and
$> 10\ \mathrm{dBm}$
at 80 °C).