Laser emission from a 1.5‐&mgr;m wavelength InGaAsP/InP diode was shown to be efficiently converted to visible or to near‐infrared light by Er‐containing infrared‐excitable phosphors. The visible emission has been markedly enhanced in Yb‐sensitized phosphors under 0.97‐&mgr;m wavelength auxiliary light irradiation especially under weak 1.5‐&mgr;m wavelength excitation. The enhancement mechanism has proved to be Yb‐sensitized quantum counter action.