Performance comparisons between direct NRZ and gain-switched RZ modulation on Fabry-Perot lasers

We firstly study the performance comparisons between direct non-return to zero and gain-switched return to zero data formats on a Fabry-Perot laser. With high speed electrical AND gate, we also investigate the relation between the pulse width of electrical drive signal and the quality of optical eye diagrams. It is found that shorter pulse width of electrical signal can completely eliminate the pattern effect and the sensitivity of RZ format is 3.8-dB better than NRZ format at data rate = 2.488-Gbps.