Brief introduction of OLT equipment

In the application of PON (Passive Optical Network: passive optical network) technology, OLT equipment is an important central office equipment, and its functions are:

1. Connect to the front-end (aggregation layer) switch with a network cable, convert it into an optical signal, and use a single fiber to interconnect with the optical splitter at the user end.

2. Realize the functions of control, management and ranging of the ONU of the user terminal equipment.

3. Like ONU equipment, OLT equipment is also an optoelectronic integrated equipment.

EPON network consists of three parts: OLT, ODN and ONU. The OLT belongs to the equipment on the service node side of the access network, and is connected to the corresponding service node equipment through the SNI interface to complete the service access of the access network.

It mainly completes the upstream access of the PON network and connects with the ONU equipment through the ODN network (composed of optical fibers and passive optical splitters) through the PON port. Generally, 1:32 or 1:64 is used to form the entire PON network. Generally, the PON port is connected to the ODN network through a single optical fiber, the optical splitter is 1:n (n=2, 4, 8, 16, 32, 64, etc.), the ONU downlink adopts the broadcast mode, and the ONU equipment selectively receives. The uplink adopts the sharing method. The development of PON technology has gone through the process of APON/BPON, EPON and GPON, and is evolving to 10G PON and WDM PON. PON technology has been widely adopted due to its flexible deployment and gradual cost reduction, and has become the main mode of current fixed broadband access.

PON network diagram

PON network diagram

The OLT is connected to the central office equipment. If the optical signal is too strong (sometimes the loss of the optical signal is small due to the short distance), an attenuator needs to be added. The OLT is connected to the ONU, and an optical splitter is connected between the two