  Electrically-pumped lasers directly grown on silicon are key devices
interfacing silicon microelectronics and photonics. We report here, for the
first time, an electrically-pumped, room-temperature, continuous-wave (CW) and
single-mode distributed feedback (DFB) laser array fabricated in InAs/GaAs
quantum-dot (QD) gain material epitaxially grown on silicon. CW threshold
currents as low as 12 mA and single-mode side mode suppression ratios (SMSRs)
as high as 50 dB have been achieved from individual devices in the array. The
laser array, compatible with state-of-the-art coarse wavelength division
multiplexing (CWDM) systems, has a well-aligned channel spacing of 20 0.2 nm
and exhibits a record wavelength coverage range of 100 nm, the full span of the
O-band. These results indicate that, for the first time, the performance of
lasers epitaxially grown on silicon is elevated to a point approaching
real-world CWDM applications, demonstrating the great potential of this
technology.
