Experimental studies on efficient frequency doubling in glass optical fibers

Experiments were carried out in order to investigate efficient second-harmonic generation in phosphor-doped glass fibers. Peak conversion efficiencies > 5% corresponding to peak powers> 1 kW at 0.53 microm have been obtained. By measuring the side light emitted and also by cutting the fibers, both the second-harmonic output power and the generation rate were studied along the fiber. Other measurements, including the polarization and mode structure of the frequency-doubled output, are also described.