What is a PLC splitter?

A PLC splitter, also referred to as a planar lightwave circuit, is a passive optical device that is widely used in passive optical networks.A PLC splitter divides one or two beams of light evenly into multiple beams or combines multiple beams of light into one or two beams. Available splits are 1x4, 1x8, 1x16, 1x16,1x32 and 1x64 PLC splitters.

The PLC splitter is produced with 0.9 mm single-mode fiber optic cable and SC, LC, FC, and ST fiber optic connectors. Of course PLC splitters are available with no connectors, which is easy to splice.

                                                                                                                                                         Figure1:PLC splitter          

Why do we need a PLC splitter?

The PLC splitter is one of the most important passive optical components in the modern fiber optic communication system. It splits optical signals, which are widely used for the following:

1. Data Center: PLC fiber splitters are used in data center networks to distribute fast data.  It is possible to transmit optical signals efficiently and quickly.

2.Optical Access Networks: PLC fiber splitters are frequently used in FTTH and FTTB. It provides end users with high-speed network service.

3.Medical Equipment: PLC fiber splitters are used in medical equipment such as endoscopes. Due to it, medical experts can view photos from different perspectives and get a better understanding of the internal structure of the patient’s body.

With the rapid growth of FTTx , the requirement for larger split configurations (1x32, 1x64, even 1x128 ) in these networks has also grown in order to serve mass subscribers.  Due to the performance benefits and overall low cost to deploy, PLC splitters are now the ideal solutions for users.

How Does a PLC Splitter Work?

PLC (Planar Lightwave Circuit) optical splitter offers a better solution for applications where larger split configurations are required. To achieve this, waveguides are fabricated using lithography onto a silica glass substrate, which allows for routing specific percentages of light. As a result, PLC splitters offer very accurate and even splits with minimal loss in an efficient package.

The PLC splitter enables a signal on an optical fiber to be distributed among two or more fibers. Generally speaking, when a fiber optic signal is transmitted in a single mode, all the light energy can’t be concentrated in the fiber core. The optical waveguide array is located on the upper surface of the chip, and the branching function is integrated on the chip; the multi-channel optical fiber arrays at the input and the output are respectively coupled at both ends of the chip and packaged.

What is the difference between an FBT and a PLC splitter?

Based on different manufacturing techniques, there are PLC splitters and FBT splitters.

PLC splitter is based on Planar Lightwave Circuit technology. It divides signals equally and is denoted with a 1xN or 2xN split ratio, where the first number is the number of inputs and N is the number of outputs. PLC splitters are high-quality with low failure rates that offer precise equal splitting for 1260 nm to 1650 nm operating wavelengths.

An FBT splitter (fused biconic tapered), also referred to as a fiber optic coupler, is traditional technology that involves the fusion of several fibers from the side of each fiber. The fiber optic coupler is used in the telecommunication industry.

Here are the differences in technical characteristics between an FBT splitter and a PLC splitter:

If you want to learn more about the differences，you can check the article “What is the difference between a PLC splitter and an FBT splitter?

Types of PLC Splitter

The types of PLC splitters mainly depend on their packaging, which can be categorized into bare fiber optic splitters, blockless fiber optic splitters, ABS module fiber optic splitters, fiber optic splitter LGX modules, fiber optic splitter 19-in racks,and universal splitter modules (USM). More information you can learn from the article “How much do you know about fiber optic splitter?”

How to Choose the Right PLC Splitter?

Generally speaking, a superior PLC splitter needs to pass a series of rigorous tests as follows:

Insertion Loss (IL): It refers to the reduction value of the optical signal at a specified output port relative to the total totainput optical signal of the PIC splitter at the working wavelength.

Return Loss (RL): It refers to the ratio in dB of the reflected light (scattered light that continuously propagates to the input end) to the input light at the fiber optic connection point. The larger the return loss, the better, in order to reduce the impact of reflected light on the light source and the system.

Directivity: It refers to the ratio of the output optical power of the non-injected light on the same side to the injected optical signal of the PLC splitter when it is working properly.

Polarization Dependent Loss (PDL): It refers to the maximum change in output optical power of the PLC splitter at each output port when the polarization state of the transmitted optical signal changes from fully polarized.

Splitting ratio: Defined as the output power of the splitter output port in the system application, which is related to the wavelength of the transmitted light.

Isolation: Indicates a light path optical splitter to other optical paths of optical signal isolation.

                                                                                                                                                   Figure 2: Test for PLC splitter          

Conclusion

PLCs enable a signal on an optical fiber to be distributed among two or more fibers. They are widely used in most fiber-optic networks. Thus, choosing fiber optic splitters is very important. A qualified PLC splitter must meet all technical performance requirements.