Interplay of four-wave mixing processes with a mixed coherent-incoherent pump

We experimentally demonstrate the existence of multiple, simultaneous, independent four-wave mixing processes in optical fibers. In particular we observe competition between phase-matched and non-phasematched processes involving the same mixed coherent-incoherent pump. Further investigation reveals that narrow-band degenerate four-wave mixing with an incoherent pump can lead to efficient wavelength conversion.