1.There is bubble or crack in the contact during fusion
This may be a poor fiber cutting, such as the end face tilt, burr or the end face is not clean, and the optical fiber needs to be cleaned again before fusion operation; another is to prevent the aging of the electric electrode, and the electrode rod needs to be replaced.
2.Too thick fusion connection or thinning of contact
The thick fusion and coarsening of the joints are often caused by the excessive feeding and too fast push of the optical fiber. Generally, the feeding amount and the discharge arc are not enough to narrow the welding joints and the contacts. The parameters of arc protection and fiber feeding are all needed to be adjusted.
3.The loss after shrinkage is larger than before the heat shrinkage
This is because the fiber is polluted after the protective sheath is stripped. When the shrink tube is tightened after the fusion, the residual pollutants (such as small sand particles) will compress the fiber, which will cause the fiber to deform, so the welding loss will become larger. At this time, the fiber needs to be cleaned and fused again.
4.Short fiber or increase loss caused by disk fiber
After the fiber fusion is finished, when fixing in the joint box, it should be handled gently to ensure that the fiber is above the minimum bending radius. The joint box should also be placed carefully to avoid squeezing and collision.
5.The mechanical strength of the fusion joint is poor and easy to be broken
There are many reasons for this situation:
① The quality of the fiber itself is not good;
② The uneven cutting surface of the fiber leads to poor fusion effect;
③ The personnel of the fusion joint side have improper force when the tray is stuck.
6.Negative loss in connection
Negative loss occurs in connection, which is a upward trend on the test curve. It is often found that the small diameter of the mode field is smaller when the diameter of the mode field is small, because the ability of the fiber with small mode field diameter to guide the backscatter light is stronger than that of the fiber with larger mode field diameter.
In this case, we should use the two-way test average method to calculate the true loss of the melting point!