Transition excitation at 0. 9. mu. m by multiphoton pumping of Nd sup 3+ -doped fibers

Multiwavelength oscillations near 0.9 {mu}m (i.e., 0.88--0.98 {mu}m) have been obtained in a Nd{sup 3+}-doped silica-based single-mode optical fiber. The laser pump wavelength is 1.064 {mu}m, with an average pump power of approximately 1.8 GW/m{sup 2}. The observed emission rate has reached a few percent. We discuss the possibility that this fluorescence or perhaps superfluorescence arises by multiphoton absorption.