On the basis of the model formed by DFB-LD, this paper presents some thorough discussion on efficiency-bandwidth product.It also points out that the promotion of efficiency is of special importance.

• 建立了DFB-LD的宏观电路模型，并对此模型进行了诸如效率带宽积等问题的深入讨论，指出提高效率有特别重要的意义。