A novel technique for the electronically-controllable generation and switching of transverse modes within a multi-mode fiber laser oscillator is presented. Preliminary results demonstrate individual transverse mode lasing and fast switching between modes with watt-level output powers. When applied to a core-pumped Tm-doped silica fiber laser with a multimode core the fundamental mode (LP_01), the next higher order mode (LP_11), or a donut-shaped LP_11 superposition were selectively excited with power levels in excess of 5 W. Fast switching between LP_01 and LP_11 modes at up to 20kHz was also realized.