An optical attenuation system that includes first and second attenuators providing different attenuations of corresponding received optical signals. The first attenuator receives an optical signal emitted by a transmitter of a first transceiver and delivers the received optical signal to a receiver of a second transceiver. The second attenuator receives an optical signal emitted by a transmitter of the second transceiver and delivers the received optical signal to a receiver of the first transceiver. A method may include determining first and second optical attenuations for the first and second attenuators, respectively, and for at least one attenuator, arranging a first fiber optic cable having a first core size in series with a second fiber optic cable having a second core size to provide the determined corresponding optical attenuation.