PDF of this tutorialThe passive elements of an EPON are located in the optical distribution network (also known as the outside plant) and include single-mode fiber-optic cable, passive optical splitters/couplers, connectors, and splices. Active NEs, such as the OLT and multiple ONUs, are located at the end points of the PON. Optical signals traveling across the PON are either split onto multiple fibers or combined onto a single fiber by optical splitters/couplers, depending on whether the light is traveling up or down the PON. The PON is typically deployed in a single-fiber, point-to-multipoint, tree-and-branch configuration for residential applications. The PON may also be deployed in a protected ring architecture for business applications or in a bus architecture for campus environments and multiple-tenant units (MTU).
Figure 3. Passive and Active NEs of a PON
