Insertion loss is usually specified in decibels (dB). It is calculated as 10 times the base-10 logarithm of the ratio of the input power to the output power. What are typical insertion loss values for fiber optic components? A typical fiber connector has an insertion loss of around 0. Engineers consider. Insertion Loss (IL) – measures how much signal power is lost when light passes through a component. Understanding both IL and RL is essential for designing reliable networks, especially in. Fiber Optical Test has become a trusted B2B leader in fiber optic testing technologies across North America.