In order to solve the problems of poor stability,high cost and low ba ndwidth of traditional light sources in wavelength division multiplexing (WDM) system,an ultra-wideband and flat light source generator structure is proposed in this paper.The proposed structure consists of cascaded electrical absorption modulator and two frequency modulators.A high bandwidth and low flatness multi-carrier light source with the same and tunable frequency interval is produced.In the case of a single wavelength optical signal,a multi-carrier light source composed of 21subcarriers with large range and tunable frequency spacing is generated,and the flatness is less than 0.2dB.When the frequency of driving signal is 8GHz and 9GHz,the flatness can reach 0.07dB.In the case of multi-wavelength optical signals,the ultra-wideband and flat light source with frequency interval of 15GHz and 275comb lines withi n 0.9dB power variation is produced and the spectrum width is able to be more than THz level.Ultimately,t he influence of several parameters on the multi-carrier light source under 10GHz driving signal is studied,inclu ding the phase difference of driving signal between electrical absorption modulator and frequency modulator,the frequency de viation of frequency modulator and the chirp factor of electrical absorption modulator.The results show that wh en the phase difference of the driving signal fluctuates in ±10°,the flatness changes at most by 1.05dB.When the fre quency deviation of frequency modulator varies within 10GHz,the fl uctuation amplitude of the flatness is only 0.1dB,indicating that the system has good stability and controllability.