We report on a single-pass device that efficiently converts the broadband near-infrared output from a femtosecond fiber laser into a narrow spectrum in the visible. With fan-out poled $\mathrm{Mg}\mathrm{O}:\mathrm{Li}\mathrm{Nb}{\mathrm{O}}_3$ we obtain subpicosecond, continuously tunable pulses in the $520–700\mathrm{nm}$ range. Conversion efficiencies as high as 30% are observed at typical pump power levels of $30\mathrm{mW}$ , corresponding to average output powers up to $9.5\mathrm{mW}$ . The specifications of our device are ideal for applications in confocal microscopy and frequency metrology.