Fiber optic loss, also known as optical attenuation, refers to the light loss between the transmitter and receiver. The estimate, called a "loss budget" is calculated using typical component losses for. When testing fiber optic cabling, determining acceptable loss is crucial. Contractors often install, terminate, and certify cabling without knowing the client's specific requirements. Factors causing fiber loss are various, such as intrinsic material absorption, bending, connector loss, etc.