The disclosure is directed to a radio over fiber (RoF) network node, base station, and communication system. In one of the exemplary embodiments, the disclosure is directed to a radio over fiber (RoF) network node which includes not limited to: a laser source which transmits a first laser beam having a first wavelength; a first Electroabsorption Modulated Laser (EML) which modulates a first electrical signal into a second laser beam that is modulated and has a second wavelength; and a first optical coupler which is coupled to the laser source and the EML and transmits an output laser beam having a first carrier frequency which is determined based on a difference between the first wavelength and the second wavelength.