Information Transferring between a Photon's Orbital Angular Momentum and Frequency

A photon's orbital angular momentum (OAM) offers a promising resource for the higher-dimensional quantum information process, which is due to the infinite values of OAM. One of the obstacles for its application is that it is difficult to transmit information encoded in OAM space in long distance quantum communication, e.g., photons with different OAMs are unsupported in optical fiber transmitting. We propose an efficient scheme to transform the information from OAM to frequency. Then the information encoded in frequency freedom can be used in fiber transmission and finally be recovered to OAM from frequency. Our scheme can be easily extended to higher-dimensional quantum information transferring between OAM and frequency.