Frequency-modulation continuous-wave (FM-CW) ladar is a new kind optical incoherent ladar. In its emission source, how to get a broadband modulated high-power continuous laser emission is the key technology. Two kinds of “seed laser” source, CQF935/5624 and EM650, are studied respectively. The performance of the related devices is tested and the results are given. The modulation performance is researched by conducting a series of experiments. The influence of the nonlinear factor on the modulation performance is discussed. The experimental results indicate that both the two “seed laser” sources have a good modulation performance, which can lead to a further application in the future. EM650 has more advantages for its integration.