Efficient multiple visible light generation in a polarization-preserving optical fiber pumped by a 1.064-μm yttrium aluminum garnet laser

Abstract
Visible light generation by sum‐frequency mixings in a polarization‐preserving fiber has been observed with pumping by a 1.064‐μm Q‐switched, and mode‐locked neodymium:yttrium aluminum garnet laser. The visible light has been efficiently generated when the fast axis of the test fiber was excited. The total conversion efficiency from the pump to all visible wavelengths amounts to 1% with a mode‐locked pump peak power of 18 kW. By fusion splicing two fibers with different visible emission lines, we have succeeded in combining those two visible spectra into one spectrum.