Enhancement of frequency comb bandwidth in gain-switched integrated semiconductor lasers via mutual coupling

Optical frequency combs (OFCs) are important tools utilised across a range of applications, including high-speed telecommunications [1]. OFCs are spectra comprised of equally spaced spectral carriers known as comb lines, with a fixed phase relationship between each line. Many generation methods have been shown to be successful in producing OFCs with the desired properties of comb line spacing, bandwidth, and spectral flatness for a given application. A single comb source which contains many comb lines in a wavelength division multiplexing system can be used instead of multiple single channel lasers, helping to alleviate the increasing burden on modern optical networks. The integration of this comb source onto a photonic chip would allow for further reduction of cost, complexity and energy requirements for optical networks.