The function of the optical splitter: ① Divide a main light source into 1-N optical paths through the splitter;
② It is to combine 1-N optical paths through a splitter into one beam of main light source for recycling!
Working principle: When a single-mode fiber transmits an optical signal, the energy of the light is not completely concentrated in the core, and a small amount is propagated through the cladding close to the core, that is to say, between the two fibers If the fiber cores are close enough, the mode field of the light transmitted in one fiber can enter the other fiber, and the optical signal is redistributed in the two fibers
Technical realization: There are currently two types of optical splitters that can meet the needs of light splitting: one is the fused tapered fiber splitter (Fused Fiber Splitter) produced by traditional optical passive device manufacturers using the traditional tapered coupler process , one is a planar optical waveguide splitter (PLC Splitter) produced based on optical integration technology. These two devices have their own advantages. Users can choose these two different types of optical splitters reasonably according to different application occasions and needs. The following is a brief introduction to the two devices for reference.
Fused Fiber Splitter
Fused taper technology is to bundle two or more optical fibers together, and then melt and stretch them on the taper machine, and monitor the change of the split ratio in real time.
The fiber (the rest is cut off) is used as the input end, and the other end is used as the multi-channel output end. At present, the mature tapering process can only draw less than 1×4 at a time. For devices above 1×4, use multiple 1×2 to connect together. Then the whole package is divided into
in the router box.
The main advantages of this device are (1) The tapered coupler has more than 20 years of history and experience, many equipment and processes only need to be used, and the development cost is only a few tenths or even a few hundredths of PLC ( 2)
The raw materials are only easy-to-obtain quartz substrates, optical fibers, heat-shrinkable tubes, stainless steel tubes and a little glue, and the total does not exceed one dollar. The investment and depreciation costs of machines and instruments are less, and low-channels such as 1×2 and 1×4 Minute
Router cost is low. (3) The splitting ratio can be monitored in real time as needed, and unequal splitters can be made.
The main disadvantages are (1) The loss is sensitive to the optical wavelength. Generally, devices should be selected according to the wavelength. This is a fatal flaw in the use of triple play, because the optical signals transmitted in triple play are 1310nm, 1490nm,
1550nm and other wavelength signals.
(2) The uniformity is poor. The nominal maximum difference of 1X4 is about 1.5dB, and the difference of 1X8 or more is even larger, which cannot ensure uniform light splitting and may affect the overall transmission distance. (3) Insertion loss varies greatly with temperature (TDL) (4) Multiplexers (such as 1×16, 1×32) are relatively large in size, reliability will be reduced, and installation space is limited.