The present disclosure is directed to systems and methods for calculating a modal time delay and a modal bandwidth. For example, a method may include: transmitting an intensity-modulated light through a mode conditioner to generate a mode-conditioned intensity-modulated light; transmitting the mode-conditioned intensity-modulated light through an optical fiber under test (FUT) to excite a plurality of modes of the optical FUT; converting the mode-conditioned intensity-modulated light transmitted through the optical FUT into an electrical signal; measuring, based on the electrical signal, a transfer function or a complex transfer function of the optical FUT based on at least on one pair of the plurality of modes; calculating a modal delay time of the optical FUT based on the transfer function or the complex transfer function; and calculating a modal bandwidth of the optical FUT based on the modal delay time, the modal bandwidth being calculated for any given launch conditions of the plurality of modes.