1x4 odn (optical distribution network)
splitter is a passive device used to connect olt and onu, distributing down link data and integrating uplink data. the splitter includes an uplink fiber port and several downlink fiber ports. optical signal from uplink fiber port is distributed to all the downlink fiber ports, and optical signal from downlink ports is assigned to the only one-uplink fiber port. there is fiber loss existed during this process.
splitter is installed in the fiber distribution box (indoor type or outdoor type); if mdu （multi dwelling unit） is distracted from each other and there is not enough fiber resource, second level and multilevel splitter is supported.
to choose the splitter ratio, there is several conditions need to consider: epon system transmission distance, amount of mdu users, and bandwidth in the system.
