1 Table 4-1 gives typical results. Use the power budget calculations described below to determine the actual distances. 2 Complies with Bellcore GR-253 Intermediate Reach Specification. The power budget is the amount of light available to overcome attenuation in the optical link and to exceed the minimum power that the receiver requires to operate within its specifications. Proper operation of an optical data link depends on modulated light reaching the receiver with enough power to be correctly demodulated.
Attenuation is significantly lower for optical fiber than for other media.
The power lost over the data link is the sum of the component, dispersion, and modal losses. If the power margin is positive, the link usually will work. Table 4-3 lists the factors that contribute to link loss and the estimate of the link loss value attributable to those factors. After calculating the power budget minus the data link loss, the result should be greater than zero. Circuits whose results are less than zero may have insufficient power to operate the receiver.