High-Fidelity Frequency Converter in High-Dimensional Spaces

High-dimensional frequency converter provides an enticing promise for establishing frequency interfaces to connect various physical systems toward the next generation of high-capacity optical communication. The constant pursuit of high fidelity accompanied by multi-dimensional information coding is restricted by the inherent fundamental nature of the degrees of freedom. Here, a high-dimensional frequency converter is theoretically proposed and experimentally demonstrated, which builds a high-fidelity interface between near-infrared and blue-violet wavelength. The perfect Poincar & eacute; beam exploiting the mutual orthogonality and transverse structure-invariance of perfect vortex beam, accesses high-dimensional spaces from spatial amplitude, phase, and polarization, and realizes the fidelity above 99% for arbitrary Poincar & eacute; states. Additionally, the trans-spectral multiplexing utilizing the radial degree of freedom endows a superior capability in further increasing the system capacity. This proof-of-principle demonstration represents a key step toward the lossless transmission between different frequency domains, and has great prospects for constructing high-capacity optical communication networks.