A passive mode-coupled fiber oscillator includes a bidirectional loop, a unidirectional loop, and a 3x3 coupler. The bidirectional loop and the unidirectional loop are coupled to one another via the 3x3 coupler. The bidirectional loop includes a first amplification fiber that is doped using at least one element selected from the group consisting of ytterbium, neodymium, erbium, thulium, and holmium. The fiber oscillator further includes a dispersion compensation element. The fiber oscillator has an anomalous dispersion overall.