Analysis of Factors And Optimization Measures of Fiber Optic Fusion Splicing Loss

1. Engineering design, construction and maintenance work should be used in the same characteristics of high-quality optical fiber

Try to use the same batch of high-quality optical fiber on a line. For the same batch of optical fiber, its mode field diameter is basically the same, the fiber at a certain point of disconnection, between the two ends of the mode field diameter can be regarded as the same, and thus in this disconnection point splicing can make the mode field diameter of the fiber splicing loss is reduced to a minimum. Therefore, the cable manufacturer is required to try to use the same batch of bare fiber, according to the requirements of the cable length of continuous production, in each disk on the sequential numbering and separation of A, B end, do not jump number.

2. Cable construction should be strictly in accordance with the regulations and requirements

Try to do the whole disk configuration (single disk ≥ 500m) to minimize the number of joints. Laying of fiber optic cables must be laid according to the number along the determined routing order, and to ensure that the B end of the former tray of fiber optic cables and the latter tray of fiber optic cables connected to the A end, so as to ensure that the splicing can be fused at the point of disconnection, and to minimize the value of the fusion loss.

Cable erection in accordance with the requirements of the cable laying construction, the cable is strictly prohibited to play small circles and folding, twisting, 3km of cable must be more than 80 people construction, 4km must be more than 100 people construction, and equipped with 6 to 8 walkie-talkies; in addition, "the front walk after the heel, the cable on the shoulder," the method of cable release, can effectively prevent the occurrence of the back of the buckle. The traction force does not exceed 80% of the allowable cable, the maximum instantaneous traction force does not exceed 100%, the traction force should be added to the cable's reinforcing parts. Laying fiber optic cable should be strictly in accordance with the requirements of fiber optic cable construction, so as to minimize the probability of damage to the optical fiber in the construction of fiber optic cable, to avoid damage to the fiber optic core resulting in increased fusion loss.

3. Select experienced and well-trained splicing personnel for splicing and testing

The level of splicing personnel directly affects the size of the splice loss, splicing personnel should be strictly in accordance with the fiber optic fusion splicing process for splicing, strict control of connector loss, always use the optical time domain reflectometer (OTDR) to monitor the process of fusion splicing (splicing loss ≤ 0.08dB / one), which does not meet the requirements of the fusion splicing should be re-splice. According to the principle of OTDR test and the standard regulations when using optical time domain reflectometer (OTDR), the loss of the joints should be measured from two directions, and then find out the average value of these two results, and use the average value as the final test results. In order to eliminate the error caused by the difference in the diameter of the mold field of unidirectional OTDR measurement.

4. Ensure that the connection environment meets the requirements

Strictly prohibit open-air operation in dusty and humid environments; fiber optic cable splicing parts and tools, materials should be kept clean, do not let the fiber optic connector moisture; ready to cut the optical fiber must be clean, no dirt. After cutting the fiber shall not be exposed in the air for too long. Splicing environment temperature is too low, should take the necessary measures to warm up.

5. Preparation of perfect fiber optic end face

The preparation of fiber optic endface is the most critical process of fiber optic splicing. Fiber optic end face is perfect or not is one of the important reasons for deciding the fiber optic splice loss. High-quality endface should be flat, no burrs, no defects, and perpendicular to the axis, the fiber optic endface axis inclination should be less than 0.3 degrees, presenting a smooth and flat mirror, and keep clean to avoid dust contamination. Should also choose a high-quality cutting knife, and the correct use of cutting knife cutting fiber. Bare fiber cleaning, cutting and fusion splicing should be close together, not too long an interval. When moving the optical fiber, it should be gently held and placed to prevent damage to the fiber end face by rubbing with other objects.

6. Correct use of fusion splicer

Correct use of fusion splicing machine is to reduce fiber optic splicing loss and an important guarantee and key link.

① should be strictly in accordance with the operating instructions and operating procedures of the fusion splicer, the correct operation of the fusion splicer.

② Reasonable placement of optical fibers, optical fibers placed into the V-shaped groove of the fusion splicer, the action should be light. This is because for a single-mode fiber with a core diameter of 10 nm, the radial offset of the fiber axis should be less than 0.8 nm if the fusion splicing loss is less than 0.1 dB.

③Set the fusion splicing parameters correctly and reasonably according to the fiber type (pre-discharge current, time and main discharge current, main discharge time, etc.).

④ Dust in the fusion splicer should be removed in time during and after use (especially dust and fiber optic debris in the fixture, each mirror and V-groove).

⑤ The service life of the electrode of the fusion splicer is generally about 2,000 times, and the electrode will be oxidized after a long period of use, resulting in a large discharge current and an increase in the value of the fusion splicing loss. At this time, you can remove the electrode, with alcohol dipped in medical cotton wool gently wiped and then mounted on the fusion splicer, and discharge cleaning once. If the discharge current is still large after repeated cleaning, the electrode must be replaced.