3 recommends a maximum value of 0. ) (This does not include the connectors that plug into the end equipment. This value should be determined by the system designer. Here are the details and instructions about each field and how they contribute to the calculation: 1. Attenuation Coefficient (dB/km): This value represents the inherent signal loss per kilometer of. The FBB Calculator is a simple yet powerful online tool that calculates the total fiber optic link loss (in decibels, dB) by factoring in losses caused by: By entering these values, users can instantly determine the total loss for a fiber optic link, enabling better system design, troubleshooting. This value should be determined by the system designer. 5 dB/km at 1300 nm for standard multimode fibers. It is caused by various factors.