The performance of tunable directly modulated 1.55‐μm InGaAsP/InP microring lasers is investigated for the case of multiband orthogonal frequency division multiplexing (MB‐OFDM) signal transmission, for application in ultra wideband (UWB)‐over‐fiber links. The assessment is based on numerical results derived from a multimode rate equation model. The properties of the microring laser are examined both qualitatively and quantitatively via typical constellation diagrams and error vector magnitude (EVM) calculations, respectively. The results depict a minimum EVM of less than 10% when the modulation ratio is in the order of 0.17 to 0.27.