The system i have attached is divided into two systems.One for conversion of wavelength or multiple wavelenghts with modulated data steam and 2nd one from direct laser.
1)A 10G data stream modulated with NRZ followed by MZM is fed to EAM.Broad in spectrum can be seen i n OSA2
2)Direct laser fed to EAM and broadened spectrum realized at OSA4.
Note:- With change of sine gen. freq. the spectrum changes,so by adjusting the SINe Gen freq. more or less broaden spectrum can be observed.