Why am I experiencing high insertion loss?

Here are some specific factors that contribute to high insertion loss:

1. Contamination (Dirt or Dust) – Even tiny particles of dirt or dust on the fiber connector end faces can obstruct or scatter light, resulting in high insertion loss.
2. Misalignment of Fibers – If the fiber cores are not perfectly aligned (due to poor connector installation or fiber damage), the light will not pass efficiently from one fiber to the other.
3. End-face Damage or Scratches – A damaged or scratched fiber end-face can lead to poor light transmission and increased insertion loss.
4. Improper Polishing – If the fiber end is not polished correctly, it can result in irregularities that prevent efficient light transmission.
5. Air Gaps – Even a small air gap between connected fibers can cause signal loss due to reflection or scattering of the light.
6. Connector Type Mismatch – Using incompatible connector types (e.g., different polishing styles such as PC, UPC, or APC) can lead to higher insertion loss.

Proper cleaning, alignment, and installation of fiber connectors are critical to minimizing insertion loss.