Nowadays fiber optic splicing is widely deployed in telecommunications, LAN, and networking projects. Typically, fiber optic splices can be undertaken in two ways: fusion splices and mechanical splices. Fusion splicing is a permanent connection of two or more optical fibers by welding them together using an electronic arc. It is the most widely used method of splicing as it provides for the lowest loss, less reflectance, strongest, and most reliable joint between two fibers.
There are many occasions when fiber optic splices are needed when there is an available fiber optic cable is not long enough for the required distance. In this case is possible to make a permanent connection. Splicing is also designed to restore fiber optic cables when they are accidentally broken.
There are two available types of fiber optic cable splicing. Both methods provide much lower insertion loss compared to fiber connectors.
Fusion Splicing
Fiber optic cable fusion splicing provides the lowest-loss connection and has a longer life than mechanical splicing. The fusion method fuses the fiber cores together with less attenuation. Special equipment called fusion splicer is used to perform the fiber fusion splicing. The fusion splicer performs optical fiber fusion splicing in two steps:
- Precisely align the two fibers.
- Generate a small electric arc to melt the fibers and weld them together.
High precision fusion splicers are usually bulky and expensive. With proper training, a fiber splicing technician can routinely achieve less than 0.1 dB insertion loss splicing for both single-mode and multimode fiber cables. When adopting this method, fusion splicing machines are often used. Generally, there are four basic steps in the fusion splicing process:
1. Strip the fiber
The splicing process begins with the preparation for both fiber ends to be fused, and you need to strip all protective coating, jackets, tubes, strength members, and so on, just leaving the bare fiber showing.
2. Cleave the fiber
Cleave the fiber is crucial to a successful fusion splice. The cleaver just nicks the fiber and then pulls it to cause a clean break rather than cut the fiber.
3. Fuse the fiber
Aligning and melting are the main steps when fusing the fiber. First, the ends must be aligned within the fiber optic splicer, and once alignment is done an electrical arc must be used to melt the fibers and permanently weld the two fiber ends together.
4. Protect the fiber
A typical fusion splice has a tensile strength between 0.5 and 1.5 lbs and it is not easy to break during normal handling. However, it still requires protection from excessive bending and pulling forces. With the help of heat shrink tubing, silicone gel, and mechanical crimp protector, the splice can be protected from outside elements and breakage.
Mechanical Splicing
Mechanical splicing is an optical junction where the fibers are precisely aligned and held in place by a self-contained assembly, not a permanent bond. The mechanical splices are normally used when splices need to made quickly and easily. Like the fusion splice, there are four basic steps for the mechanical splice.
1. Strip the fiber
In this step, the protective coating, jacking, tubes, strength members must be removed to show the bare cores. It is noted that the cables should be cleaned.
2. Cleave the fiber
When cleaving the fiber, you need to obtain a very clean cut which is exactly at right angles to the axis of the fiber.
3. Mechanically join the fiber
You have to join the fibers mechanically with no heat. Simply connect the ends of fiber together inside the mechanical splice unit and the device will help couple the light between two fibers.
4. Protect the fiber
Once fibers are spliced, protection will be needed during light transmission. Typically, the completed mechanical splice provides its own protection for the splice.
Fusion and mechanical splicing both have their specific advantages and disadvantages. When it comes to choosing fusion or mechanical splicing that is up to the customer’s needs. The fusion splice offers a lower level of loss and a high degree of performance. It gives very low back reflections and is preferred for single-mode high-speed digital or CATV networks but it requires the use of expensive equipment. Mechanical splicing is deployed for applications where splices need to be made quickly. Choosing the appropriate method, whether the fusion splicing or mechanical splicing, can not only save money but also enhance work efficiency. Besides, when you are doing fiber optic splicing, it is necessary to follow the steps strictly and carefully.
