Q: What is acceptable loss in fiber optics? A: For singlemode fiber, loss should be under 0. Q: How do I know if fiber loss is too high? A: Compare your results with standard loss limits. High readings mean connectors, splices, or bends need. Significant signal loss (i., fiber optic loss) occurs within the fiber due to light absorption and scattering, affecting the reliability of optical transmission networks. Understanding and managing it is critical to. Fiber loss, or attenuation, refers to the reduction in optical power as light travels through a fiber optic cable.