对正色散光纤激光器中耗散孤子的形成过程进行了数值模拟。数值模拟结果表明增益色散对耗散孤子的形成起决定性作用。耗散孤子的陡峭光谱边缘是正色散效应、光纤非线性效应、增益和损耗以及增益色散效应之间共同作用的结果。窄增益带宽可以导致多个耗散孤子的形成，与此同时，宽的增益带宽(以100 nm为例)在抽运强度足够的条件下可以支持耗散孤子的形成。即使激光腔内不存在其他光谱限制效应，耗散孤子仍可以在具有宽增益带宽的光纤激光器中形成。

The transient process of dissipative soliton (DS) generation is numerically revealed in normal dispersion fiber lasers. It is shown that the gain dispersion is critical for the DS generation. The steep spectral edges of DSs are the consequence of the interaction among the normal dispersion, fiber nonlinearity, gain and loss, and gain dispersion effect. Narrow gain bandwidth could result in multiple DSs while broad gain bandwidth (up to 100 nm) could support DS generation provided that enough pump power is available. Consequently, DSs could be generated in fiber lasers even when the gain bandwidth is broad and there is no requirement for other spectral filtering in cavity.