Novel performance of fiber lasers: tunable operation in visible range

A review of the main physical processes important for frequency doubling of fiber lasers and the results of development by the Novosibirsk group of the fiber lasers operating from blue-green to yellow-red spectral ranges with a potential of the broad continuous tuning are presented. These lasers with ～100 mW power are treated to be attractive light sources for applications in medicine, especially in confocal microscopy and flow cytometry.