What is the decay of the PLC Splitter? How to choose and use PLC Splitter

- Oct 29, 2020-

What is the decay of the PLC Splitter? How to calculate?

There are four common technical indicators for PLC Splitters: wavelength, insertion loss, additional loss, and splitting ratio.

The main indicator of the PLC Splitter is the different light attenuation produced by the PLC Splitter under a specific splitting ratio. Under the conditions of different splitting ratios, the light attenuation of the PLC Splitter will not be different.

Optical attenuation value of PLC Splitter = transmit optical power + additional loss + insertion loss + bare fiber loss.

1. PLC Splitter split ratio calculation

Formula: ki=Pi/SP*100%

Among them, Pi is the required driving power of each optical link, and SP is the sum of the required driving power of each optical link carried by the laser.

Note: In actual use, we have indicated the splitting ratio, such as 80% for one point two: 20% or 70%: 30%; one point three for 70%: 15%: 15%; one point four for 70%: 10 %: 10%: 10%.

2. Calculation of additional loss

Generally, the loss of 1×N single-mode standard PLC Splitter is as follows:

Number of branches













Additional loss/dB













The above are also our regular standards.

3. Insertion loss calculation

Formula: IL=-10lg(Po/Pi)

Among them, Po is the optical power at the output end, and Pi is the optical power at the input end.

Note: Po/Pi in the formula is equivalent to the splitting ratio of the PLC Splitter, namely: IL=-10lg(ki). For example, there is a one-to-two PLC Splitter, which is a two-eight split, that is, the splitting ratio is 20%:80%. The theoretical value of the insertion loss of the 20% split optical link is -10lg (20%), which is approximately equal to 6.99dB.

4. Bare fiber loss calculation

In fact, this value does not need to be calculated and has a certain reference standard. It is necessary to strictly refer to numerical standards to measure the loss values of different wavelengths to determine the final loss value.


Fiber attenuation coefficient (reference value)







PS: Active connector attenuation: generally 0.5dB each.

types of PLC Splitters? How to choose PLC Splitter?

PLC Splitters can be divided into box-type PLC Splitters, tray-type PLC Splitters, rack-mounted PLC Splitters, wall-mounted PLC Splitters, etc. according to different application ranges. Box-type PLC Splitters are generally used for optical fiber distribution boxes, etc.; tray-type PLC Splitters are generally used for ODF optical fiber distribution frames and optical cable transfer boxes in the computer room, etc.; rack-mounted PLC Splitters are installed in standard racks ; The wall-mounted PLC Splitter can be installed on the wall.

PLC Splitters can be divided into two types according to different manufacturing processes: fusion tapered PLC Splitters and planar waveguide (PLC) PLC Splitters. Among them, planar waveguide PLC Splitters (PLC) are widely used In FTTx and PON. The fusion taper PLC Splitter is formed by fusion splicing two or more optical fibers on the side; the planar waveguide PLC Splitter (PLC) is a micro-optical component type product, using photolithography technology, on the dielectric or semiconductor substrate An optical waveguide is formed to realize the branch distribution function. The splitting principles of these two types of PLC Splitters are similar. They both achieve different branch amounts by changing the evanescent field coupling between the fibers (coupling degree, coupling length) and changing the fiber radius.

How to choose among the above types of PLC Splitters?

We can first determine the application occasions, and choose the appropriate PLC Splitter according to actual needs. For example, in applications where there are few splits and insensitive to optical wavelengths (that is, only 1×2 or 1×4 is sufficient), select fusion pull Cone PLC Splitter; if it is used in FTTH and other applications that require multiple wavelengths (that is, 1×4 or more), choose a planar waveguide (PLC) PLC Splitter, because the planar waveguide (PLC) PLC Splitter The light distribution is uniform and the channel is uniform.

Principles and planning of PLC Splitter

Commonly used PLC Splitters have split ratios of 1:2, 1:4, 1:8, 1:16, 1:32, 1:64. If necessary, you can also choose 2:N PLC Splitter or non- Evenly split PLC Splitter. When configuring the PLC Splitter, the maximum utilization rate of each PON port and PLC Splitter of the equipment must be considered. According to the user distribution density and distribution form, the optimal PLC Splitter combination method and suitable installation position must be selected. There are two principles for the use of PLC Splitters:

One is to try to use the first level of light splitting as much as possible, and the second is that the number of light splitting levels does not exceed the second level.

There are three reasons for using the first-level splitting: first, it can maximize PON utilization; second, it is convenient to diagnose faults; third, the system has high reliability. So how to place the PLC Splitter?

(1) The first-level splitting method is adopted. When the PLC Splitter is in the resident network, the PLC Splitter can be installed indoors or outdoors. The indoor installation locations include the central computer room of the community, the weak current well in the building, and the floor line box. The upper connecting optical cables of the PLC Splitter can come from the first-level optical junction box, the second-level optical junction box or the optical fiber splitting box. This method is mainly suitable for the situation of large scale and high user density, such as high-rise residential buildings.

(2) If the secondary optical splitting method is adopted, the PLC Splitter can be installed on the backbone layer or the user distribution cable layer. In the backbone layer, the splitter can be installed on the primary optical junction box, secondary optical junction box or Inside the optical fiber distribution box. This method is suitable for situations where users are relatively scattered and new user optical cable networks.

How to use PLC Splitter?

With the large-scale advancement of fiber to the home (FTTH) in China, the application of various optical passive products has developed rapidly. As the most core passive optical device in the construction of fiber to the home (FTTH), PLC Splitters are used to ensure communication Important equipment for normal link transmission. So how are PLC Splitters used in fiber to the home (FTTH) cabling?

Currently, primary and secondary spectroscopy are often used in engineering. As for the first-level splitting method, the use of PLC Splitters is generally divided into four situations: one is placed in the central office computer room; the second is placed in the cell computer room; the third is placed in the cell optical transfer box; the fourth is directly placed in corridor. For the secondary PLC Splitter, the use of PLC Splitter is generally divided into three situations: one is that the primary PLC Splitter is placed in the central office's computer room, and the secondary PLC Splitter is placed in the optical transfer box; the second is the primary PLC Splitter. The splitter is placed in the large-capacity optical junction box next to the road, and the secondary PLC Splitter is placed in the cell optical junction box; the third is the primary PLC Splitter is placed in the cell optical junction box, and the secondary PLC Splitter is placed in the cell optical junction box. The device is placed in the corridor.



With the progress of optical network transformation, more and more PLC Splitters are used, and the quality of PLC Splitters has an increasing impact on optical networks. Choosing a suitable, effective, and economical PLC Splitter and manufacturer will allow us to get twice the result with half the effort during network transformation, while effectively reducing the amount of investment and cost in maintenance and management in the future.