Single-mode fiber optic cables have a core diameter of about 9µm, operate at wavelengths like 1310nm or 1550nm, deliver very low attenuation, and support long-distance transmissions without losing signal quality. This is achieved by using high-quality materials and advanced manufacturing processes to ensure that the cable has minimal. We measured attenuation in decibels per kilometer (dB/km). 15 dB/km for single-mode fibers, but for plastic fibers, it's over 300 dB/km. Many factors cause fiber attenuation. 3 dB/km at. Although attenuation is significantly lower for optical fiber than for other media, it still occurs in both multimode and single-mode transmissions. Dispersion is the spreading of the signal over time.