Comparison of photon-pair generation rate between the sideband and fundamental modes of spontaneous four-wave mixing

Spontaneous four-wave mixing (SpFWM) in fiber optics has been investigated due to its high photon-pair generation rate and negligible connection loss to fiber optic systems. Photon pairs generated in the fundamental or sideband modes satisfy SpFWM's phase matching condition, and the pair-generation efficiency of both modes has been considered nearly identical. Here, we directly compare the pair-generation efficiency of the fundamental and sideband modes. Dispersion in optical fiber varies unevenly, and SpFWM in the sideband mode is more sensitive to the medium's dispersion properties than in the fundamental mode, inducing lower pair-generation efficiency. These strong non-uniformity effects in the sideband mode will affect the photon-pair generation and four-wave mixing based quantum and nonlinear applications.