The entangled states of light with quantum correlations of quadrature amplitude and phase components are the key resources for realizing the continuous variable quantum communication and quantum calculation. With the rapid development of quantum information science, researching and establishing practicable quantum information networks have become the main goal pursued by scientists in this field. For developing the long-distance transfer of quantum information via quantum repeaters, it is essential to prepare multipartite entangled states consisting of multi-color optical sub-modes respectively at fiber transmission and atomic transition frequencies. We briefly introduce the concept and the development of the continuous variable entangled optical fields firstly, then summarize the generation experiments of two-color and three-color entangled optical fields. At last the generation principle and the experimental method of three-color entangled optical fields at the atomic transition frequency and the communication window of optical fibers accomplished by our group recently are presented detailedly.