Chromatic Dispersion Diagnosis for the Two-Modes of Few-Mode Photonic Crystal Fiber

We provide the differential group delay (DGD) and chromatic dispersion for the fundamental and first higher order modes traversing a large-core few-mode photonic crystal fiber (PCF). The modal interferometer method is used to measure the DGD and chromatic dispersion for the fundamental mode at a wavelength of
$\sim 1300$
nm and in the 1450–1625-nm telecommunication band. The combined measurement of the DGD and chromatic dispersion makes it possible to obtain the chromatic dispersion of the higher order mode. The chromatic dispersion diagnosis for the two modes is discussed. In the 1450–1625-nm band, the results obtained experimentally for the two modes exactly match those obtained from the empirical relations for PCF dispersion.