Basic knowledge of optical splitter

Optical splitter is a component of PON network. It is a passive device connecting OLT and ONU. Its function is to distribute downstream data and concentrate upstream data. The optical splitter has one upstream optical interface and several downstream optical interfaces. The optical signal from the upstream optical interface is distributed to all the downstream optical interfaces for transmission, and the optical signal from the downstream optical interface is distributed to the only upstream optical interface for transmission.

Only when the optical signal is transferred from the upstream optical interface to the downstream optical interface, the optical signal strength/optical power will decrease, and the same is true when the optical signal is transferred from the downstream optical interface to the upstream optical interface. The optical signal strength from each downstream optical interface may be the same or different.

Working principle: When a single-mode fiber transmits an optical signal, the light energy is not completely concentrated in the core, and a small amount is transmitted through the cladding close to the core, that is, in the two fibers. If the cores are close enough, the mode field of light transmitted in one fiber can enter the other fiber, and the optical signal is redistributed in the two fibers.

fiber optic splitter

Optical Splitter Loss Calculation

Optical power loss is related to the number of optical branches (~3.5dB loss per 1:2 split)

The loss of optical power determines the distance that can be transmitted

Bandwidth vs. cost: The average available bandwidth of each household depends on the size of the optical splitting ratio. The larger the optical splitting ratio, the lower the cost per household of the OLT.

Splitter type

According to the different manufacturing processes, optical splitters are mainly divided into two categories: FBT type (fused taper type optical splitter) and PLC type (planar optical waveguide power splitter).

The fusion taper technology is to bundle two or more optical fibers together, and then melt and stretch them on the taper machine. During the stretching process, the coupling and splitting ratio of each fiber is monitored. After the splitting ratio reaches the requirements, the melting and stretching is terminated, and one end is reserved. One fiber (the rest is cut off) is used as the input end, and the other end is used as the multiplex output end.

Process principle of FBT type optical splitter

Planar optical waveguide technology is based on optical integration technology, using semiconductor technology to make optical waveguide branch devices, and the function of branching is completed on the chip.

Process principle of PLC type optical splitter

According to the application range, it can be divided into: box-type optical splitter, tray-type optical splitter, rack-type optical splitter, wall-mounted optical splitter, etc.

Cassette splitter is mainly used in the ODF rack in the computer room, in the optical cable transfer box, etc.

Cassette Splitter

The tray-type optical splitter can only be installed in the ODF rack of the equipment room or in the optical cable transfer box.

Tray beam splitter

Rack mount splitters can only be installed in standard racks.

The wall-mounted optical splitter is installed on the wall and can be installed in corridors and corridors.