Optical frequency combs in quantum dot fabry-perot lasers: Role of the spatial hole burning

The transmission of huge amount of data at Tbit/s rate in short distance optical interconnect has successfully employed quantum dot (QD) or quantum dash (QDash) multi-wavelength lasers (optical frequency combs) integrating one single section laser chip with the silicon photonics modulators. The “comb” characteristics (i.e. self-phase locking of the lasing wavelengths separated by one cavity free spectral range) of single section QD and QDash lasers have been demonstrated in several experimental works, but the understanding of the fundamental physical effects behind the comb generation is still ongoing.