Highly efficient 750 W tapered double-clad ytterbium fiber laser.
The results of theoretical and experimental studies of active tapered double-clad fibers, intending the optimization of its imperative parameters--tapering ratio, longitudinal profile, core/cladding diameters ratio, are presented. Using a refined taper geometry we have demonstrated power scaling of a ytterbium fiber laser pumped by low-brightness, cost-effective laser diodes up to 750 W, with 80% efficiency.