We present the investigation on chromatic dispersion characteristics of three orbital angular momentum (OAM) states in 5.58 km ring-core fiber (RCF) link. Steady transmissions of different OAM mode orders spanning from -2 to +2 via the 5.58 km RCF are demonstrated, ensuring the stability of dispersion measuring system. For OAM0,1+, OAM+1,1+, and OAM+2,1+, the chromatic dispersion values of 13.8 ps/(nm·km), 20.1 ps/(nm km), and 32.9 ps/(nm· km) are obtained, respectively. Experiments are also carried out on the measurements of dispersion-induced power fading of the radio-frequency (RF) signal in the OAM transmission link, and the results match well with the values calculated from the measured chromatic dispersion.
