There are generally three methods for fiber optic fusion splicing: fusion splicing, flexible splicing, and mechanical splicing. In practical engineering, fusion welding is generally used because it has low node loss, high reflection loss, and high reliability.
The principle to be followed when splicing optical cables is that when the number of cores is the same, the corresponding color fibers in the same bundle tube should be used; When the number of cores is different, the large cores are melted first and then the small cores are connected in order. Common optical cables include layer twisted, skeleton, and center bundle cables. The colors of the cores are divided into blue, orange, green, brown, gray, white, red, black, yellow, purple, pink, and green in order. Multi core optical cables place fibers of different colors in the same bundle to form a group, so there may be several bundles inside one optical cable. Facing the cross-section of the optical cable, the red bundle tube is regarded as the first bundle of the optical cable, and clockwise it is green, white 1, white 2, white 3, etc.
2. The fusion process of optical cable
The first step is to peel off the optical cable and fix it into the splice box. When fixing multi bundle tube layered optical cables, due to the need for layered fiber winding, each bundle tube should be placed in order to avoid entanglement. Thread the optical cable into the splice box and secure the steel wire tightly without any looseness. Otherwise, it may cause the fiber core of the optical cable to roll. Be careful not to damage the tube bundle. Take a stripping length of about 1 meter and wipe the ointment clean with toilet paper.
The second step is to pass the optical fiber through the heat shrink tubing. Separate fibers of different bundles and colors and thread them through heat shrink tubing. The fiber optic cable with stripped coating layer is very fragile. Using heat shrink tubing can protect the fiber optic joint.
Step three, turn on the power of the welding machine and select the appropriate welding method. The power supply of the fusion splicer has two types: DC and AC, and should be switched reasonably according to the type of power supply current. Before each use of the welding machine, it should be left in the welding environment for at least 15 minutes. Set fusion parameters, pre discharge time, time, and main discharge time according to the type of fiber optic cable. If there are no special circumstances, the automatic welding program is generally chosen. Remove dust and fiber optic debris from the fusion splicer in a timely manner during and after use.
Step four, make the fiber end face. The quality of fiber end face production will directly affect the quality of splicing, so it is necessary to have a qualified end face before fusion splicing.
Step five, Clean the Bare Fiber: Tear the cotton into small, flat pieces, stick a little alcohol, clamp the stripped fiber, wipe along the fiber axis with moderate force, and use different parts and layers of cotton each time to improve cotton utilization.
Step six, the cutting of bare fibers, first clean the cutting blade and adjust its position. The placement of the cutting blade should be stable, and the cutting action should be natural, smooth, and not heavy or light. Avoid the occurrence of bad end faces such as fiber breakage, skew angle, burrs, and cracks. Step seven, place the fiber optic cable into the V-shaped groove of the fusion splicer, carefully press the fiber optic pressure plate and fiber optic fixture, set the position of the fiber optic cable in the pressure plate according to the cutting length of the fiber optic cable, close the windproof cover, press the fusion splicing button to automatically complete the fusion splicing, and the estimated loss value will be displayed on the fusion splicer screen. Step eight, remove the fiber and heat it in the fusion splicer furnace. Even if the fusion is completed, if necessary, the optical cable line can still be tested for faults