Single-mode fiber optic cables are more suitable for long-distance, high-speed transmission than multimode fiber optics. For most applications, the maximum distance of a single-mode cable is around 160 kilometers. However, the dispersion-compensating fibers can support more. The cable plant "loss budget" is a function of the losses of the components in the cable plant - fiber, connectors and splices, plus any passive optical components like splitters in PONs. Thus the loss budget of the cable plant is a major factor in the power budget of the fiber optic link and is. Link Loss = [fiber length (km) x fiber attenuation per km] + [splice loss x # of splices] + [connector loss x # of connectors] + [safety margin] For example, Assume a 40km single mode link at 1310nm with 2 connector pairs and 5 splices. 5 dB per kilometer at 1550nm, light absorption and scattering still accumulate over long spans. Chromatic dispersion, modal dispersion, mechanical stress, bending losses, connectivity issues, and other environmental factors further curtail distance. The goal is to achieve the lowest possible optical loss (signal.
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