Epon system by the local equipment Olt (optical line Terminal, optical circuit terminals), user-side equipment ONU (optical Network Unit, optical Network units) and optical distribution network ODN (optical distribution Network, optical distribution network.
Olt and ONU between optical fiber, optical splitter and other optical passive devices, no need to rent a room, no need to supply power, no source equipment maintenance personnel, therefore, can effectively save the construction and operation maintenance costs.
Epon uses the Ethernet transmission format is also the user's LAN/resident network Mainstream technology, the two have the natural fusion, eliminates the complex transmission protocol transformation brings the cost factor; Epon transmits the transceiver signal on a fiber, which is called single fiber bidirectional transmission mechanism. The technology used is WDM (wavelength division multiplexing, Wavelength Division multiplexing) technology, using different wavelengths (downlink 1490nm, uplink 1310nm) to achieve up and down data transmission, to achieve on a single fiber transmission at the same time the upper and lower row of the stream without mutual influence, As shown in the following figure. In the downlink direction, the signal sent by Olt is broadcast to all users, the uplink direction, each ONU uses TDMA (Time Division ListBox Access) technology. The downlink shares bandwidth by encrypting broadcast transmissions for different users.
Epon can provide 1. Gbit up and down line bandwidth, transmission distance up to $number km, support for maximum optical tap ratio 1:64, thus greatly reducing the cost pressure of olt and backbone fiber. High-speed broadband, fully meet the bandwidth requirements of access network customers, and can be easily flexible according to user needs change dynamic allocation of bandwidth; dot to multi-point structure, only to increase the number of ONU and a small amount of user-side fiber can easily expand the system to upgrade, fully protect the operator's investment.
Epon has the ability to transmit TDM, IP data and video broadcasts simultaneously, in which TDM and IP data are transmitted in the format of IEEE 802.3 ethernet, and the network management system is supported by the telecommunication level, which is enough to guarantee the quality of transmission. Video business broadcast transmission can be achieved by extending a third wavelength (usually 1550nm).
With the development of Ethernet technology Epon can be upgraded to 10G Epon, in Beijing, the 2009 China FTTH Summit Development Forum, ZTE launched the world's first "symmetrical" 10G epon equipment prototype.