We demonstrate 308 mW of single-mode laser emission at 464 nm from a frequency doubled picosecond fiber based Master Oscillator Power Amplifier (MOPA). The laser system consisted of a gain-switched and spectrally narrowed Fabry-Perot laser diode emitting at 928 nm, which was amplified in a two-stage amplifier based on W-type double-clad Nd-doped fibers. Output pulses with a duration of 90 ps at a repetition rate of 41 MHz were frequency-doubled in a periodically poled MgO-doped Congruent Lithium Niobate. A conversion efficiency of 14.8% was achieved in single-pass configuration.