Modal noise BER calculations in 10-Gb/s multimode fiber LAN links

In this letter, we explore the modal noise penalty dependence on the laser launch conditions. We present calculations that are using the actual launch conditions of the laser, and the actual fiber transfer function, instead of making approximations to the calculation of the standard deviation of the modal noise. The results suggest that in 10-Gb/s multimode local area network links and for laser launches of interest, the laser encircled flux should be limited to 18 mu m at 1300 nm and 19 mu m at 850 nm. This would result in no links exceeding their allocation of modal noise penalty in the link power budget. These encircled flux values are in compliance with the requirements for sources used with OM3 fiber.