Facilities

Compact, power-efficient, mass-producible low noise semiconductor passively mode-locked lasers (MLLs) are
important because they can generate ultra-stable high frequency pulse trains and coherent frequency combs that can
be employed in dense wavelength-division multiplexing (DWDM), high speed optical time-division multiplexing
(OTDM), interchip/intrachip clock distribution, arbitrary waveform generation, millimeter wave signal generation,
gas sensing, and spectroscopy [1-6]. Low noise passive mode-locking operation is usually obtained by lowering the

A fully integrated heterogeneous silicon/III-V colliding pulse mode-locked laser with tunable on-chip optical feedback operating in the O-band is extensively investigated. The 19-GHz colliding pulsed laser operates in a wide mode-locking regime with good mode locking quality. By precisely controlling the strength and phase of the on-chip optical feedback signal, the laser exhibits clear periodic pulse shortening effects. The RF 3 dB linewidth was reduced by a factor of 4.7 down to 6 kHz, as compared to the free running state.