Through considering the output cavity mirror, fast axis collimation lens, chips welding, cooler designing and so on, we have widely understood the necessary consideration for the phase locking DLA in an EC. 通过分析输出腔镜、快轴准直透镜、芯片焊接、冷却器设计等关键的环节,对外腔锁相需要考虑的问题进行了深入的探讨。