Precautions for Fiber Connection

Fiber breakage is very common, what should I do if the fiber optic cable breaks? How are fiber optic cables spliced? The following is an introduction to the connection method of fiber optic cable, for your reference!

Fiber optic cable connection method introduction

1. Steps/methods

1. Strip the optical cable and fix the optical cable in the splice box. Be careful not to damage the bundle tube. The stripping length is about 1m. Wipe off the ointment with toilet paper. Put the optical cable into the splicing box. When fixing the steel wire, it must be pressed tightly so that there is no looseness. Otherwise, it may cause the optical cable to roll and break the core.

2. Split the fiber through the heat shrinkable tube. Separate different bundle tubes and fibers of different colors, and pass them through the heat shrinkable tube. The optical fiber with the coating stripped off is very fragile, and the heat-shrinkable tube can be used to protect the optical fiber fusion splice.

3. Turn on the power of the fusion splicer, use the preset program to perform fusion, and remove the dust in the fusion splicer in time during and after use, especially the dust and fiber fragments in the fixture, mirrors and V-shaped grooves. The optical fiber used by CATV includes conventional single-mode optical fiber and dispersion-shifted single-mode optical fiber, and there are two kinds of operating wavelengths: 1310nm and 1550nm. Therefore, before fusion splicing, the appropriate splicing procedure should be selected according to the optical fiber and working wavelength used in the system. If there are no special circumstances, the automatic welding program is generally used.

4. Make the fiber end face. The quality of the optical fiber end face will directly affect the splicing quality, so it is necessary to make a qualified end face before welding. Use a special wire stripper to peel off the coating layer, and then wipe the bare fiber several times with alcohol-soaked cleaning cotton, with moderate force, and then use a precision fiber cutter to cut the fiber. For 0.25mm (outer coating) fiber, The cutting length is 8mm-16mm, and for 0.9mm (outer coating) optical fiber, the cutting length can only be 16mm.

5. Place the optical fiber. Put the optical fiber in the V-shaped groove of the fusion splicer, carefully press the optical fiber clamp and the optical fiber clamp, set the position of the optical fiber in the clamp according to the cutting length of the fiber, close the windshield, and the fusion splicing can be completed automatically, which only takes 11 seconds.

6. Remove the optical fiber and heat the heat-shrinkable tube with a heating furnace. Open the windshield, take the fiber out of the fusion splicer, put the heat shrinkable tube in the center of the bare fiber, and heat it in a heating furnace. The heater can use 20mm miniature heat shrink tubing and 40mm and 60mm general heat shrink tubing. It takes 40 seconds for 20mm heat shrink tubing and 85 seconds for 60mm heat shrink tubing.

7. The disk fiber is fixed. Coil the spliced optical fiber onto the fiber storage tray. When the fiber is coiled, the larger the radius of the coil and the larger the arc, the smaller the loss of the entire line. Therefore, a certain radius must be maintained to avoid unnecessary loss when the laser is transmitted in the fiber core. 8 Seal and hang. The field connection box must be sealed well to prevent water from entering. After the fusion splice box is flooded with water, due to the long-term immersion of the optical fiber and the optical fiber splicing point in water, the attenuation of some optical fibers may first appear to increase. Slip on stainless steel hooks and hang on hanging wires. So far, the optical fiber fusion splicing is completed.

2. Matters needing attention

1. The optical fiber is a delicate and fragile device, so be careful when operating it.

2. The optical fiber is erected, and after the fusion is completed, it is the test work. The instrument used is mainly an OTDR tester, which can test the position of the optical fiber breakpoint; the entire loss of the optical fiber link; understand the loss distribution along the length of the optical fiber; Splice loss. In order to test accurately, the pulse size and width of the OTDR tester should be properly selected and set according to the index of the refractive index n value given by the manufacturer. When judging the fault point, if the length of the optical cable is not known in advance, it can be placed in the automatic OTDR first to find out the general location of the fault point, and then placed in the advanced OTDR.

Choose a smaller pulse size and width, but it should correspond to the length of the optical cable. The blind area is reduced until it coincides with the coordinate line. The smaller the pulse width, the more accurate it is. Of course, when the pulse is too small, the curve shows noise, which should be just right. Then there is the addition of a fiber detection disc, the purpose is to prevent blind spots nearby from being easy to detect.

When judging the breakpoint, if the breakpoint is not at the splice box, open the nearby splice box, connect the OTDR tester, test the exact distance between the fault point and the test point, and use the meter mark on the optical cable to easily find the fault point . When using the meter mark to find faults, there is still a problem with the twisting rate of the pair-twisted optical cable, that is, the length of the optical cable is not equal to the length of the optical fiber. The length of the optical fiber is about 1.005 times the length of the optical cable. Using the above method can be successfully eliminated. Multiple breakpoints and high loss points.