PLC is the English abbreviation of Planar Lightwave Circuit, that is, Planar Lightwave Circuit. It is an integrated wave guide optical power distribution device based on a quartz substrate. Like the coaxial cable transmission system, the optical network system also needs to couple, branch and distribute the optical signal, which requires an optical splitter.

Different from traditional discrete devices, PLC devices are made by semiconductor technology, which can integrate optical components with different functions into one chip, which is the basic process technology to realize the integration, modularization and miniaturization of optoelectronic devices.

It is one of the most important passive devices in optical fiber links, and is a fiber optic tandem device with multiple input ends and multiple output ends, especially suitable for connecting central office and terminal equipment and realize the splitting of optical signals.

What are the main raw materials of PLC Splitter?

a) One of the main raw materials---chip

The PLC splitter chip is made by semiconductor technology (photolithography, etching, development and other technologies). The optical waveguide array is located on the upper surface of the chip, and the splitting function is integrated on the chip, that is, the splitting is realized on one chip. Generally speaking, the splitting ratio of each node is 50:50. Coupling the input end and the output end of the multi-channel fiber array and encapsulating the optical path of the waveguide.

b) The second main raw material - fiber array

The Fiber Array is made of V-groove. The fiber array mainly relies on the precisely scribed V-groove to achieve positioning, and uses a special bonding process to achieve precise fiber positioning and high reliability to meet different needs. The thermal expansion coefficient matching package design ensures the fiber array board is stress-free, high reliability and no fiber displacement at high temperature. The end face angles can be precisely ground as required.

The fiber spacing is the most important test item. The fiber core spacing includes two test indicators, namely the lateral distance between the fiber core and the core (called Pitch) and the longitudinal distance between them (called Deviation), the error of the two. Generally controlled within ± 0.5μm, the center spacing of adjacent fibers is l=127um/250um, d∝2um, r=125um

a) Bare PL

The bare-piece PLC optical splitter is directly led out by optical fibers (usually ribbon optical fibers), and the two ends are not terminated.

It adopts fusion splicing or cold splicing, and is suitable for optical fiber distribution trays and optical cable splice boxes.

The tray-type PLC is packaged in a plastic box, and the ports are end-to-end. There are generally beveled cassette mount adapters. Tray PLC is mainly used in distribution frame, optical cable transfer box, optical cable transfer box, etc

c) Branch PLC

Splitter PLC refers to a small optical splitter assembly that uses a small splitter box (which can be fixed on the box body) and a 0.9mm sleeve at the output end based on a bare-piece PLC

d) Rack PLC

The rack-mounted PLC is packaged in a metal box, which can be installed in a 19-inch 1U standard cabinet, and is generally end-type. Rack-type PLCs are mainly used in optical cable distribution boxes, optical fiber distribution frames, etc.

e) Modular PLC

The modular PLC is packaged in ABS plastic box, and the port is led out by pigtail. There are three types of fiber exit sleeves: 0.9mm, 2.0mm, and 3.0mm. Mainly used in fiber distribution boxes and racks.

f) Micro PLC

Refers to a small optical splitter assembly packaged in steel pipe and using a 0.9mm loose tube for fiber output. It is mainly suitable for tight installation space, such as optical cable splice box, optical fiber splitter box, and can also be installed in the combination box of plug-in type and rack-type optical splitter. No welding or cold splicing required, installed directly in the box

g) Plug-in PLC

The plug-in PLC is packaged in an ABS plastic box, and the ports are end-to-end. Mainly installed in the optical fiber junction box. Plug-in PLC is mainly used in fiber branch box.

Advantages and disadvantages of PLC Splitte

a) advantage

(1) There are many shunt channels for a single device, which can reach more than 32 channels.

(2) The multi-channel cost is low, and the more the number of branches, the more obvious the cost advantage.

(3) The structure is compact and the volume is small, which can be directly installed in various existing transfer boxes without special design to leave a large installation space.

(4) The loss is not sensitive to the wavelength of transmission light, and can meet the transmission needs of different wavelengths.

(5) The light splitting is uniform, and the signal can be evenly distributed to the user.

b) shortcoming

(1) The device manufacturing process is complex and the technical threshold is high. At present, the chip is monopolized by several foreign companies, and there are only a few domestic companies that can package and produce in large quantities.

(2) Compared with the fusion taper splitter, the cost is higher, especially in the low channel splitter.

PLC splitter has excellent optical performance, high stability and high reliability, and can be widely used in PON network. PLC splitters have different package types to meet the application requirements of different scenarios

a) Plug-in PLC splitter

The plug-in PLC splitter is installed and fixed in the plug-in box, and the interface types are SC/FC/LC, etc. It is mainly suitable for corridors or outdoor light splitting points in FTTH access mode. The commonly used 1X4, 8, 16, 32 and 2X8, 16, 32 PLC splitters are used as plug-in trays for installation in customer-specific enclosures, especially corridor enclosures.

b) Device structure

Bare fiber type PLC optical splitters leave bare fibers at all their ends. It is mainly suitable for occasions that are not disassembled frequently, such as cable connector boxes, optical fiber distribution boards, etc.

c) ABS Cassette PLC Splitter

The splitter packaged in a box is the most used type by operators at present. The ABS package is compact and the application is more flexible.

d) Rack-mounted PLC splitter

The rack-mounted optical splitter is designed for standard 19" cabinet installation, which can meet the requirements of high wiring density in data centers or server rooms. Generally, it is packaged in a metal box, which is easy to install in optical fiber projects, and is suitable for PLC splitter devices. Play a good protective role. There are various adapter mounting interfaces such as SC, LC, FC or ST connectors. Rack-mounted optical splitters are widely used in FTTX projects, cable TV systems and data communication centers.

e) Wall Mounted PLC Splitter

The cabinet of the wall-mounted PLC distributor is usually made of ABS material, which provides reliable protection for the direct connection, termination or branch connection of the optical fiber. Double-layer structure, the upper layer is a PLC splitter, and the lower layer is a fiber splice tray. The wall-mounted optical splitter is used in the terminal access link in the FTTH access system to connect and protect optical devices. The wall-mounted optical splitter is suitable for corridors, basements and computer rooms, etc. It is also suitable for outdoor wall-mounted and pole-mounted installations.

f) Micro package structur

The miniature optical splitter is a miniature steel tube package, which can be divided into pigtails with connectors and pigtails without connectors. Connectors usually come in SC, LC, FC and ST types. Can be installed in fiber optic splice boxes, module boxes, and distribution boxes.

g) Fan-Out PLC Splitter

Fan-out PLC splitter usually uses 0.9mm optical fiber, and a single fiber branch is branched through a bundle of fan-out kits, which can be terminated with different types of connectors. It can be effectively installed in fiber DP boxes, fiber splice boxes or other small terminal boxes.

h) LGX type PLC splitter

LGX is an optical splitter packaged in a small metal box, which can be installed in a 19-inch 1U/2U/3U chassis. The input and output end of the pigtail structure can be easily connected to the ODF panel adapter, saving time. LGX's compact and miniature design, plug and play, can be easily installed in fiber distribution boxes, ODF sub-frames, fiber optic terminal boxes and fiber optic cable junction boxes.