Fiber splicing is connecting two optical cables together. Another more common method of joining fibers is called termination or joining. Normally, compared with the terminal, the optical loss and back reflection of fiber splicing is lower, which makes when the cable length is too long or two different types of cables are connected together (such as connecting 48 cables to 4 12 Root cables), optical fiber splicing has become the preferred method. When a buried cable is accidentally cut, splicing can also be used to restore the fiber optic cable.
There are two methods for optical fiber splicing: fusion splicing and mechanical splicing. If you are just starting to edit, you may want to look at your long-term goals in this field to choose the technology that best suits your economic and performance goals.
1. Mechanical splicing vs. fusion splicing
- Mech anical connection:
Mechanical splices are simple positioning devices designed for aligning both ends of the fiber precisely so that light can pass from one fiber to the other. (Typical loss: 0.3 dB)
- Fusion splicing:
In welding, a machine is used to precisely align the two fiber ends, and then the glass ends are “welded” or “welded” together using some type of heat or arc. This creates a continuous connection between the fibers, which makes the optical transmission loss very low. (Typical loss: 0.1 dB)
- Which method is better?
The typical reason for choosing one method over another is the economy. The initial investment in mechanical splicing is low (1000-2000 USD), but the cost of each splicing is higher (12-40 USD). Although the cost of welding each joint is lower (0.5-1.5 US dollars each), the initial investment is much higher (depending on the accuracy and characteristics of the fusion splicer purchased, the investment is 15,000-50,000 US dollars). The more accurate your calibration requirements (the better the calibration, the lower the loss), the more you will pay for the machine.
It usually depends on what industry you are in when it comes to the performance of each splicing method. Compared with mechanical splicing, fusion splicing produces lower losses and less back reflection, because the resulting fusion splice is almost seamless. Splices made of metal and glass are mainly used for mono-mode fibers, while splices made of metal and glass are used for multimode fibers.
Many telecommunications and cable television companies invest in the fusion splicing of long-distance single-mode networks, but for shorter local cable runs, mechanical splicing will still be used. Since analog video signals require minimal reflections to get the best performance, fusion splicing is also the first choice for this application. The LAN industry can choose either method because signal loss and reflection are secondary issues for most LAN applications.
2. Fusion splicing method
As mentioned earlier, fusion splicing is to permanently bond two or more optical fibers together by electric arc welding.
Four basic steps to complete proper fusion splicing:
Step 1: Prepare the fiber-peel off the protective coating, sheath, casing, strong parts, etc., leaving only the bare fiber. The main problem here is cleanliness.
Step 2: Cutting the fiber-using a good fiber cutter is a key to successful welding. The end to be cut must be mirror-smooth and perpendicular to the fiber axis to obtain proper splicing. Note: The meat cleaver will not cut the fibers! It just scratches the fibers and then pulls or bends them, causing a clean break. The purpose of this is to produce a bifurcated end that is as perfectly vertical as possible. This is why a good fusion splicing knife usually sells for $1,000 to $3,000. These cutters can continuously produce a split angle of 0.5 degrees or less.
Step 3: Fuse-There is two steps in this step, alignment, and heating. Calibration can be manual or automatic, depending on what equipment you have. The higher the price of the equipment you use, the more accurate the calibration. Once the fusion splicer unit is properly aligned, then use the arc to melt the fiber, permanently welding the two fiber ends together.
To ensure that the fiber will not break in processing, protect it from bending and tension. The tensile strength of a typical welded joint is between 0.5 and 1.5 pounds, and it will not break during normal operation, but it still needs to prevent excessive bending and tension. Using heat shrink tubing, silicone, and/or mechanical crimp protectors will protect the joint from external elements and breakage.
3. Mechanical connection method
A mechanical connection is an optical connection in which the optical fibers are precisely aligned and held in place by a separate component, rather than a permanent connection. This method aligns the two ends of the two optical fibers with a common centerline and aligns their cores so that light can be transmitted from one optical fiber to another.
Four steps for mechanical splicing:
Step 1: Prepare the fiber-peel off the protective coating, sheath, casing, strong parts, etc., leaving only the bare fiber. The main problem here is cleanliness.
Step 2: Cutting the fiber-This process is the same as the fusion cutting, but the cutting accuracy is not so critical.
The third step: mechanically connect the fibers-this method does not require heating. Simply place the fiber ends in the mechanical splicing unit. The index matching gel in the mechanical splicing device will help couple light from one end of the fiber to the other. Old equipment will use epoxy instead of index matching gel to hold the cores together.
Step 4: Protect the fiber by completing the mechanical connection.
4. Better splicing skills
1) Clean your splicing tools often and thoroughly. When using optical fibers, keep in mind that particles invisible to the naked eye can cause huge problems when using optical fibers. “Excessive” cleaning of your fibers and tools will save you time and money.
2) Maintain and operate your meat cleaver properly. In fiber splicing, the cutting machine is the most valuable tool. In mechanical splicing, you need a proper angle to ensure a proper end face, otherwise too much light will enter the air gap between the two fibers. Index matching gel will eliminate most of the light escape, but cannot overcome low-quality splitting. You should expect to spend about $200 to $1,000 for a good quality cutter suitable for mechanical splicing.
3) For Fusion splicing, you need a more precise cutter to achieve exceptionally low loss (0.05 dB or less). If you have a bad crack, the fiber ends may not melt together, causing light loss and high reflection problems. It is estimated that it will cost 1,000 to 4,000 U.S. dollars to buy a good meat cleaver to achieve the accuracy required for fusion. Following the manufacturer’s cleaning instructions and the correct use of tools to maintain your meat cleaver will provide you with a long-lasting device and ensure that the work is done correctly the first time.
- Fusion parameters must be adjusted minimally and systematically (only for fusion splicing). If you start to change the joints on the fusion parameters once there is a hint of a problem, you may lose the settings you want. First, check the dirty equipment, and then continue to check the parameters. Splicing time and splicing current are two key factors that affect the splicing effect. Different variables of these two factors can produce the same splicing result. High-time low current and high current low time are the same results. Make sure to change only one variable at a time and keep checking until you find the correct fusion parameters for your fiber type.
