摘要 |
<p>A multimode optical fiber has a refractive index profile such that a measurement of the dispersion modal delay (DMD), carried out on a DMD graph modified by adding a delay (”t trace ) to each trace: ” �¢ t trace = ” �¢ » max �¢ xDxL �¢ r trace a ² where r trace is the center position of the injection of the light pulse corresponding to the trace, ± is the core radius of the multimode fiber, L is the length of the fiber, D is the chromatic dispersion of the multimode fiber at the wavelength of the light pulse, ² is the coefficient of the delay and ”» max is the maximum spectral width of the source intended to be used with the fiber, produces an equivalent modal dispersion value of less than 0.11 ps/m for (”» max x D) > 0.07 ps/m. The modification of the DMD graph to take account of the chromatic dispersion makes it possible to guarantee a calculated effective bandwidth EBc greater than 6000 MHz-km for multimode fibers used with multimode transverse sources.</p> |