Why is the loss of optical fiber too large after fusion?

Is this the value you tested? There are several situations in which the general loss value appears: the optical fiber transceiver will have a fixed value within 10, which depends on the quality of the product, and the better transceiver will be around 5; There will also be a certain loss value at the fusion joint of optical fiber, which depends on the quality of fusion; When the coupler is clamped, there will be loss value, such as dust or misalignment, which is greater than the loss value caused by welding. Generally, it is enough to replace the coupler.