After the optical fiber connection, the light passing through the joint part will produce a certain loss, called the fiber connection transmission loss, that is, the joint loss. Now mainly analyze the single-mode fiber connection loss factors.
1, intrinsic factors on the connection of the single-mode fiber is the largest impact on the mode field diameter. When the mode field diameter mismatch 20%, will produce more than 0.2 dB of loss. As far as possible, the use of mode field diameter of the smaller fiber, to reduce the splice loss is of great significance.
2, external factors external to the single-mode fiber splice loss generated by the main factors of axial misalignment and axial tilt. For mechanical connections and longitudinal splitting and fusion splicing of the core deformation and other factors.
(1) axial misalignment. When the misalignment reaches 1.2 μm, the loss caused by up to 0.5 dB, improve the accuracy of the connection positioning, can effectively control the impact of axial misalignment.
(2) Axial tilt. When the tilt reaches 1 °, will cause 0.2 dB loss. Choose high-quality fiber cutting knife, can improve the axial tilt caused by the loss.
(3) fiber core deformation. When the automatic fusion splicer current, advance amount, discharge current, time and other settings are reasonable, the amount of loss caused by fiber core deformation can be achieved below 0.02 dB.
