Optical comb generation and expansion by gain switched discrete mode laser diode

Optical comb generation by gain switching (GS) of a discrete mode (DM) laser diode (LD) is an attractive alternative, which in combination with a comb expansion technique allows a cost efficient, simple source, providing a highly coherent and stable output with a tuneable FSR. A demonstration of optimized and cost efficient techniques to generate an optical coherent multi-carrier signal is performed. The study of gain switching of a DM-LD will be presented along with two optical comb expansion schemes. The results will be evaluated in terms of spectral bandwidth, number of frequency tones, and extinction ratio. The experimental achievements will be compared to theoretical simulation results.