Insertion Loss: The signal power loss that occurs at a connection point. This is a key metric for measuring the quality of a fiber optic termination, with a lower value indicating better performance. For every fiber optic cable plant, you need to test for continuity and polarity, end-to-end insertion loss and then troubleshoot any problems. The process of fiber optic cable termination is the essential act of connecting fiber optic cables to devices, patch panels, or other cables to enable. Fiber optic loss, also known as optical attenuation, refers to the light loss between the transmitter and receiver.