Systems and methods for measuring a modal delay and a modal bandwidth

A system comprising:

• a mode conditioner coupled to an input end of an optical fiber under test (FUT), the mode conditioner being configured to:
• condition an intensity-modulated light to generate a conditioned intensity-modulated light;
• and
• transmit the conditioned intensity-modulated through the optical FUT;
• a detector configured to convert the conditioned intensity-modulated light transmitted through the optical FUT into an electrical signal;
• and
• a measuring system configured to:
• receive the electrical signal from the detector;
• based on the electrical signal, measure a transfer function S21 or a complex transfer function CTF(f) of the optical FUT based on at least on one pair of the plurality of modes;
• calculate a modal delay of the optical FUT based on the transfer function S21 or the complex transfer function CTF(f) ;
• and
• calculate a bandwidth of the optical FUT based on the modal delay, the bandwidth being calculated for any given launch conditions of the plurality of modes.

A method comprising:

• directing an input light signal having a first wavelength into an optical fiber under test (FUT), the optical FUT supporting a plurality of modes at the first wavelength, the plurality of modes comprising a first pair of modes, the input light propagating through the optical FUT to provide an output light signal;
• determining a transfer function S21 or a complex transfer function CTF(f) of the optical FUT at the first wavelength from a ratio of the output light signal to the input light signal;
• and
• determining a modal delay time of the first pair of modes from the transfer function S21 or the complex transfer function CTF(f).