EFFICIENT FREQUENCY UP-CONVERSION OF 1.319-MU-M RADIATION INTO INTENSE YELLOW LIGHT AT 580 NM IN PURE SIO2-CORE MONOMODE OPTICAL-FIBER

Generation of intense visible light at 580 nm with peak powers as high as 20 W through efficient frequency upconversion of 1.319-mum Nd:YAG laser pulses in a single span of pure SiO2-core single-mode optical fi ber is reported. The yellow-light signal generated at 580 nm propagate s in the LP02 mode and exhibits an asymmetrical 3.5-nm bandwidth spect rum with a long tail toward high frequencies. The frequency upconversi on process presents a threshold power, which depends on the fiber leng th, and a critical length of a few meters, at which the mechanism star ts to build up. A conversion efficiency of fundamental radiation at 1. 319 mum into visible light at 580 nm of approximately 0.5% in a 20-m l ength of pure silica-core fiber at 5.0-kW peak pump power was measured .