Enhancement of quantum entanglement between twin beams via a four-wave mixing process with double feedback

Abstract

Two port feedback has been theoretically studied and proved to be effective in enhancing the degree of entanglement of the output beams for an optical four-wave mixing process, but the loss effects and phase delays need to be further concerned. Here, we use a model that is closer to practical implementation. By reasonably tuning the coefficients, we find that higher degree of entanglement and higher power of the output beams can be obtained, and the requirement for phase locking accuracy could be looser, which means this model is more promising for practical applications in quantum computation and quantum communication.