Method for characterizing performance of a multimode fiber optical link and corresponding methods for fabricating a multimode optical fiber link showing improved performance and for improving performance of a multimode optical fiber link

A method of characterizing a multimode optical fiber link comprising a light source and at least two multimode fibers, the method comprises:

• a step of characterizing said light source by at least three source characteristic curves obtained by:
• exciting a nominal multimode fiber with said light source being directly modulated with a digital electrical signal at a nominal bit rate;
• scanning with a single mode fiber an output signal of said nominal multimode fiber, at different radial offset values r, from an axis of said nominal fiber where r=0 to a radial offset value r=a, where a is the core radius of said nominal fiber,
• analyzing with a spectrum analyzer an output optical spectrum of said single mode fiber for each radial offset value r,
• said source characteristic curves each showing a source parameter as a function of said radial offset value r;
• a step of characterizing each of said multimode fibers using a measurement of the Dispersion Modal Delay (DMD), wherein an output trace of light pulses launched into said multimode fiber at different radial offset values r is detected by using a single mode fiber and wherein said measurement of said DMD is used to calculate, for each of said multimode fibers, at least three fiber characteristic curves as a function of said radial offset value r;
• and
• a step of computing an Effective Bandwidth (EB) of said link, comprising calculating a transfer function using both each of said source characteristic curves and each of said at least three fiber characteristic curves for each of said multimode fibers.