1. star mode.
When between OLT and ONU by point-to-point configuration and each ONU directly by a special optical link with the OLT connected, in the middle there is no optical branching device consisting of a star structure. Because of this configuration there is no loss of optical splitter is introduced, so the transmission distance is far greater than the point to multipoint configuration. But the application of fiber waste is serious, can not reflect the advantages of GPON technology, less practical application.
2. way tree mode.
Tree topology is point to multipoint configurations of the basic structure, this structure using the a series of cascade distribution point (DP) of the signal splitter, passed to multiple users, but also on the distribution node uplink signal combined together give OLT. 1:N type splitter distribution points, in the important customer access, may use 2:N light to achieve the trunk fiber protection. In the application of the local network, considering the fiber network layout complex, generally use a light, for multistage, suggested control within three class.
3. Bus mode.
Bus structure is the basic structure of point to multipoint configuration. This topology, in fact, is the topology of the OLT and distribution points, and the distribution point to the ONU is still the star structure. This structure uses a series of distribution points in order to distribute the signal from the bus to the ONU to send the signal to the OLT, and can send the signal of each ONU to the bus to send back to OLT. This approach is generally used in monitoring and control system, optical device for 1:2 is divided into light, light 5:95 or 10:90 and 20:80 multiple choice, recommend the use of 10:90 light splitter, actual use in optical power calculation principles prevail, there is generally no more than 7.