The basic concept is to use passive optical components to connect remote nodes to form a ring topology, and use the ring as protection path.We design three kinds of protection structures for DWA PON.

• 设计的基本想法是将远端节点加上一个被动的分光元件用来将远端节点串联来形成一个环形网路，以这个环形网路来做为保护线路，提供网路意外断讯时的另一条路径。