Professional bandwidth calculator for multimode fiber systems. In multimode fibers, different modes travel at. This Applications Engineering Note (AE Note) discusses bandwidth characterization for multimode optical fiber (MMF), and bandwidth's impact on overall system performance. The bandwidth of such fiber is determined for various layouts of air holes and widths of Gaussian launch. This calculator provides an estimate of Bandwidth-Length Product (BL) based on fiber properties. BL is a measure related to modal dispersion, but it's not directly equivalent. Calculation Example: The bits per second (BPS) that can be transmitted through a multimode fiber cable is calculated by multiplying the bandwidth (in MHz) by 1,000,000.