Modal bandwidth

Modal Bandwidth in the disciple of telecommunications, refers to the signalling rate per distance unit. The signalling rate can typically be measured in Mhz, and the modal bandwidth is expressed as Mhz-km. .

The modal bandwidth of a multimode fiber is determined from the optical output power frequency spectrum. The frequency at which the amplitude drops three decibels [dB] relative to the zero frequency component of the fiber is defined as the -3 dB bandwidth (or modal bandwidth) of the fiber (see Figure 1).